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troubleshooting rotary lobe pumps | pumps & systems

troubleshooting rotary lobe pumps | pumps & systems

The rotary lobe pump belongs to the positive displacement pump family. It is a dual shaft pump design with external timing gears, allowing two intermeshing rotors to operate synchronously. The pump operation is similar to the function of a positive displacement blower: Minimized clearances between rotors and the pump casing allow pumping action by forming a seal with the liquid between the suction and discharge side. Most positive displacement pumps need to be operated with elastomers (progressive cavity pumps, hose pumps, diaphragm pumps, plunger pumps, etc.). Since the rotary lobe pump incorporates a timing gear, non elastic rotors like steel or stainless steel rotors can also be used. Since the rotary lobe pump has no preferred rotation direction, it can be operated in a reversible mode. Industries and Markets Rotary lobe pumps are utilized in almost every industry with the major distinction existing between the sanitary and non-sanitary markets. The sanitary market needs lobe pumps with CIP (Cleaning In Place) and SIP (Sterilization In Place) capabilities. Materials of construction for product wetted parts are stainless steel and higher grade materials with highly finished surfaces. The all metal rotors are machined to allow only the smallest clearances to the casing. To prevent zones where fluid can accumulate in the pumps, the number of parts in contact with the fluid is minimized. For example, no wear plates or pump casing protection plates are incorporated in sanitary lobe pump designs. The non-sanitary lobe pump market includes many industries: for example, water and wastewater, oil and gas, biofuels, pulp and paper, marine, sugar and chemical industries. For these markets, the pumps are often exposed to harsher, more abrasive fluids. There is little need for CIP or SIP, but many non-sanitary lobe pumps are MIP (Maintenance In Place), which allows the replacement of all fluid wetted parts onsite without the removal of any pipe systems or drive mechanisms. This often allows the use of sacrificial wear plates and other features for easy maintenance and cost effectiveness over the entire life cycle. Applications and Troubleshooting This article focuses on non-sanitary lobe pumps. To ensure a successful rotary lobe pump installation, many factors play a role. To name a few: expectations of customer and vendor, fluid characteristics, flow and pressure, process and pipe design, space constraints, maintainability, availability of spare parts, downtime, etc. Municipal Market Wastewater Treatment Plants (WWTP) require lobe pumps for various sludge applications. They are used for handling abrasive and viscous fluids, often feeding thickening and dewatering devices. A recent addition for rotary lobe pump applications has been filtration, especially membrane bioreactors utilized for wastewater treatment. Submerged micro- or ultra-filtration membranes are installed upstream from a rotary lobe pump, on average one pump unit per train. The rotary lobe pump pulls the filtered water through the membranes (permeation); as necessary, the reversible operation capabilities are used to back-flush the membranes for a cleaning cycle. The key here is SIMPLICITY. The reversible operation of the rotary lobe pump simplifies the pipe design and the PLC programming of an MBR system in comparison to a centrifugal pump. Also, a wide flow and differential pressure range can be targeted with variable speed operation. Wastewater Treatment Plants Under abrasive conditions, ease of maintenance of a rotary lobe pump is important for operations of WWTPs. With many rotary lobe pumps, all fluid wetted parts are replaceable through the front cover, allowing repairs and/or modifications onsite, minimizing downtime. The wide variety of available rotor designs and materials in the rotary lobe pump market allows troubleshooting and reduction of life cycle cost through optimization in the aftermarket. Modular pump designs allow various rotors to fit in the same pump casing. Example: Initially, a rotary lobe pump equipped with a dual lobe rotor is installed to feed a dewatering belt press. The pump operates according to the performance curve, but pulsation and vibration damages the pipe system. The solution is the screw rotor: The low pulsation characteristic of this rotor designs allows a smooth flow compared to a centrifugal pump, eliminating the vibration problems. The screw rotor design also accounts for success of rotary lobe pumps in the MBR Market. With the high flows required and no abrasion being present, the pump units are operated at speeds up to 500 rpm, where the screw rotor eliminates pulsation problems. Variable Frequency Drives By incorporating a variable frequency drive (VFD), the metering capabilities of rotary lobe pumps (flow is proportional to operation speed) can be utilized. The rotary lobe pump has a constant torque characteristic, required torque is unchanged at different operation speeds with constant discharge pressures. Most VFDs can be used for dynamic and constant torque operation, the constant torque operation generally reduces the HP rating of the VFD. Because of the reduced HP rating, some rotary lobe pump units could not be operated because the VFD was calculated for dynamic torque operation so it was undersized for the rotary lobe pump. Renewable Energy Market A relatively new market is the biofuels industry, especially ethanol and biodiesel production. New process solutions often demand new developments from pump manufacturers. Biodiesel Plants Biodiesel plants require various pump applications. While soybean oil is often used as primary feedstock, the use of various additives throughout the biodiesel production process requires high rate materials of construction. Rotary lobe pumps utilized in this industry usually are equipped with pump casings from stainless or duplex steel. With rotor elastomers, various kinds of FPM have been used, tested and often failed. The solution is rotary lobe pumps equipped with PTFE or stainless steel rotors, dynamic o-rings from Chemraz 505, static o-rings from PTFE. As a rotor material, PTFE is often not possible with other rotary positive displacement pumps since it is a cold flowing material. The timing gear with a non-contacting rotor synchronization allows the use of PTFE for rotary lobe pumps. Chemical Industry Specialty Chemical Plant In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up. The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances. To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

The rotary lobe pump belongs to the positive displacement pump family. It is a dual shaft pump design with external timing gears, allowing two intermeshing rotors to operate synchronously. The pump operation is similar to the function of a positive displacement blower: Minimized clearances between rotors and the pump casing allow pumping action by forming a seal with the liquid between the suction and discharge side. Most positive displacement pumps need to be operated with elastomers (progressive cavity pumps, hose pumps, diaphragm pumps, plunger pumps, etc.). Since the rotary lobe pump incorporates a timing gear, non elastic rotors like steel or stainless steel rotors can also be used. Since the rotary lobe pump has no preferred rotation direction, it can be operated in a reversible mode. Industries and Markets

The sanitary market needs lobe pumps with CIP (Cleaning In Place) and SIP (Sterilization In Place) capabilities. Materials of construction for product wetted parts are stainless steel and higher grade materials with highly finished surfaces. The all metal rotors are machined to allow only the smallest clearances to the casing. To prevent zones where fluid can accumulate in the pumps, the number of parts in contact with the fluid is minimized. For example, no wear plates or pump casing protection plates are incorporated in sanitary lobe pump designs.

The sanitary market needs lobe pumps with CIP (Cleaning In Place) and SIP (Sterilization In Place) capabilities. Materials of construction for product wetted parts are stainless steel and higher grade materials with highly finished surfaces. The all metal rotors are machined to allow only the smallest clearances to the casing. To prevent zones where fluid can accumulate in the pumps, the number of parts in contact with the fluid is minimized. For example, no wear plates or pump casing protection plates are incorporated in sanitary lobe pump designs.

The non-sanitary lobe pump market includes many industries: for example, water and wastewater, oil and gas, biofuels, pulp and paper, marine, sugar and chemical industries. For these markets, the pumps are often exposed to harsher, more abrasive fluids. There is little need for CIP or SIP, but many non-sanitary lobe pumps are MIP (Maintenance In Place), which allows the replacement of all fluid wetted parts onsite without the removal of any pipe systems or drive mechanisms. This often allows the use of sacrificial wear plates and other features for easy maintenance and cost effectiveness over the entire life cycle. Applications and Troubleshooting This article focuses on non-sanitary lobe pumps. To ensure a successful rotary lobe pump installation, many factors play a role. To name a few: expectations of customer and vendor, fluid characteristics, flow and pressure, process and pipe design, space constraints, maintainability, availability of spare parts, downtime, etc. Municipal Market Wastewater Treatment Plants (WWTP) require lobe pumps for various sludge applications. They are used for handling abrasive and viscous fluids, often feeding thickening and dewatering devices. A recent addition for rotary lobe pump applications has been filtration, especially membrane bioreactors utilized for wastewater treatment. Submerged micro- or ultra-filtration membranes are installed upstream from a rotary lobe pump, on average one pump unit per train. The rotary lobe pump pulls the filtered water through the membranes (permeation); as necessary, the reversible operation capabilities are used to back-flush the membranes for a cleaning cycle. The key here is SIMPLICITY. The reversible operation of the rotary lobe pump simplifies the pipe design and the PLC programming of an MBR system in comparison to a centrifugal pump. Also, a wide flow and differential pressure range can be targeted with variable speed operation. Wastewater Treatment Plants Under abrasive conditions, ease of maintenance of a rotary lobe pump is important for operations of WWTPs. With many rotary lobe pumps, all fluid wetted parts are replaceable through the front cover, allowing repairs and/or modifications onsite, minimizing downtime. The wide variety of available rotor designs and materials in the rotary lobe pump market allows troubleshooting and reduction of life cycle cost through optimization in the aftermarket. Modular pump designs allow various rotors to fit in the same pump casing. Example: Initially, a rotary lobe pump equipped with a dual lobe rotor is installed to feed a dewatering belt press. The pump operates according to the performance curve, but pulsation and vibration damages the pipe system. The solution is the screw rotor: The low pulsation characteristic of this rotor designs allows a smooth flow compared to a centrifugal pump, eliminating the vibration problems. The screw rotor design also accounts for success of rotary lobe pumps in the MBR Market. With the high flows required and no abrasion being present, the pump units are operated at speeds up to 500 rpm, where the screw rotor eliminates pulsation problems. Variable Frequency Drives By incorporating a variable frequency drive (VFD), the metering capabilities of rotary lobe pumps (flow is proportional to operation speed) can be utilized. The rotary lobe pump has a constant torque characteristic, required torque is unchanged at different operation speeds with constant discharge pressures. Most VFDs can be used for dynamic and constant torque operation, the constant torque operation generally reduces the HP rating of the VFD. Because of the reduced HP rating, some rotary lobe pump units could not be operated because the VFD was calculated for dynamic torque operation so it was undersized for the rotary lobe pump. Renewable Energy Market A relatively new market is the biofuels industry, especially ethanol and biodiesel production. New process solutions often demand new developments from pump manufacturers. Biodiesel Plants Biodiesel plants require various pump applications. While soybean oil is often used as primary feedstock, the use of various additives throughout the biodiesel production process requires high rate materials of construction. Rotary lobe pumps utilized in this industry usually are equipped with pump casings from stainless or duplex steel. With rotor elastomers, various kinds of FPM have been used, tested and often failed. The solution is rotary lobe pumps equipped with PTFE or stainless steel rotors, dynamic o-rings from Chemraz 505, static o-rings from PTFE. As a rotor material, PTFE is often not possible with other rotary positive displacement pumps since it is a cold flowing material. The timing gear with a non-contacting rotor synchronization allows the use of PTFE for rotary lobe pumps. Chemical Industry Specialty Chemical Plant In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up. The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances. To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

The non-sanitary lobe pump market includes many industries: for example, water and wastewater, oil and gas, biofuels, pulp and paper, marine, sugar and chemical industries. For these markets, the pumps are often exposed to harsher, more abrasive fluids. There is little need for CIP or SIP, but many non-sanitary lobe pumps are MIP (Maintenance In Place), which allows the replacement of all fluid wetted parts onsite without the removal of any pipe systems or drive mechanisms. This often allows the use of sacrificial wear plates and other features for easy maintenance and cost effectiveness over the entire life cycle. Applications and Troubleshooting

This article focuses on non-sanitary lobe pumps. To ensure a successful rotary lobe pump installation, many factors play a role. To name a few: expectations of customer and vendor, fluid characteristics, flow and pressure, process and pipe design, space constraints, maintainability, availability of spare parts, downtime, etc.

This article focuses on non-sanitary lobe pumps. To ensure a successful rotary lobe pump installation, many factors play a role. To name a few: expectations of customer and vendor, fluid characteristics, flow and pressure, process and pipe design, space constraints, maintainability, availability of spare parts, downtime, etc.

A recent addition for rotary lobe pump applications has been filtration, especially membrane bioreactors utilized for wastewater treatment. Submerged micro- or ultra-filtration membranes are installed upstream from a rotary lobe pump, on average one pump unit per train. The rotary lobe pump pulls the filtered water through the membranes (permeation); as necessary, the reversible operation capabilities are used to back-flush the membranes for a cleaning cycle. The key here is SIMPLICITY. The reversible operation of the rotary lobe pump simplifies the pipe design and the PLC programming of an MBR system in comparison to a centrifugal pump. Also, a wide flow and differential pressure range can be targeted with variable speed operation.

A recent addition for rotary lobe pump applications has been filtration, especially membrane bioreactors utilized for wastewater treatment. Submerged micro- or ultra-filtration membranes are installed upstream from a rotary lobe pump, on average one pump unit per train. The rotary lobe pump pulls the filtered water through the membranes (permeation); as necessary, the reversible operation capabilities are used to back-flush the membranes for a cleaning cycle. The key here is SIMPLICITY. The reversible operation of the rotary lobe pump simplifies the pipe design and the PLC programming of an MBR system in comparison to a centrifugal pump. Also, a wide flow and differential pressure range can be targeted with variable speed operation.

Under abrasive conditions, ease of maintenance of a rotary lobe pump is important for operations of WWTPs. With many rotary lobe pumps, all fluid wetted parts are replaceable through the front cover, allowing repairs and/or modifications onsite, minimizing downtime. The wide variety of available rotor designs and materials in the rotary lobe pump market allows troubleshooting and reduction of life cycle cost through optimization in the aftermarket. Modular pump designs allow various rotors to fit in the same pump casing.

Under abrasive conditions, ease of maintenance of a rotary lobe pump is important for operations of WWTPs. With many rotary lobe pumps, all fluid wetted parts are replaceable through the front cover, allowing repairs and/or modifications onsite, minimizing downtime. The wide variety of available rotor designs and materials in the rotary lobe pump market allows troubleshooting and reduction of life cycle cost through optimization in the aftermarket. Modular pump designs allow various rotors to fit in the same pump casing.

Example: Initially, a rotary lobe pump equipped with a dual lobe rotor is installed to feed a dewatering belt press. The pump operates according to the performance curve, but pulsation and vibration damages the pipe system. The solution is the screw rotor: The low pulsation characteristic of this rotor designs allows a smooth flow compared to a centrifugal pump, eliminating the vibration problems. The screw rotor design also accounts for success of rotary lobe pumps in the MBR Market. With the high flows required and no abrasion being present, the pump units are operated at speeds up to 500 rpm, where the screw rotor eliminates pulsation problems.

Example: Initially, a rotary lobe pump equipped with a dual lobe rotor is installed to feed a dewatering belt press. The pump operates according to the performance curve, but pulsation and vibration damages the pipe system. The solution is the screw rotor: The low pulsation characteristic of this rotor designs allows a smooth flow compared to a centrifugal pump, eliminating the vibration problems. The screw rotor design also accounts for success of rotary lobe pumps in the MBR Market. With the high flows required and no abrasion being present, the pump units are operated at speeds up to 500 rpm, where the screw rotor eliminates pulsation problems.

By incorporating a variable frequency drive (VFD), the metering capabilities of rotary lobe pumps (flow is proportional to operation speed) can be utilized. The rotary lobe pump has a constant torque characteristic, required torque is unchanged at different operation speeds with constant discharge pressures. Most VFDs can be used for dynamic and constant torque operation, the constant torque operation generally reduces the HP rating of the VFD. Because of the reduced HP rating, some rotary lobe pump units could not be operated because the VFD was calculated for dynamic torque operation so it was undersized for the rotary lobe pump. Renewable Energy Market A relatively new market is the biofuels industry, especially ethanol and biodiesel production. New process solutions often demand new developments from pump manufacturers. Biodiesel Plants Biodiesel plants require various pump applications. While soybean oil is often used as primary feedstock, the use of various additives throughout the biodiesel production process requires high rate materials of construction. Rotary lobe pumps utilized in this industry usually are equipped with pump casings from stainless or duplex steel. With rotor elastomers, various kinds of FPM have been used, tested and often failed. The solution is rotary lobe pumps equipped with PTFE or stainless steel rotors, dynamic o-rings from Chemraz 505, static o-rings from PTFE. As a rotor material, PTFE is often not possible with other rotary positive displacement pumps since it is a cold flowing material. The timing gear with a non-contacting rotor synchronization allows the use of PTFE for rotary lobe pumps. Chemical Industry Specialty Chemical Plant In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up. The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances. To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

By incorporating a variable frequency drive (VFD), the metering capabilities of rotary lobe pumps (flow is proportional to operation speed) can be utilized. The rotary lobe pump has a constant torque characteristic, required torque is unchanged at different operation speeds with constant discharge pressures. Most VFDs can be used for dynamic and constant torque operation, the constant torque operation generally reduces the HP rating of the VFD. Because of the reduced HP rating, some rotary lobe pump units could not be operated because the VFD was calculated for dynamic torque operation so it was undersized for the rotary lobe pump. Renewable Energy Market

Biodiesel plants require various pump applications. While soybean oil is often used as primary feedstock, the use of various additives throughout the biodiesel production process requires high rate materials of construction. Rotary lobe pumps utilized in this industry usually are equipped with pump casings from stainless or duplex steel. With rotor elastomers, various kinds of FPM have been used, tested and often failed.

Biodiesel plants require various pump applications. While soybean oil is often used as primary feedstock, the use of various additives throughout the biodiesel production process requires high rate materials of construction. Rotary lobe pumps utilized in this industry usually are equipped with pump casings from stainless or duplex steel. With rotor elastomers, various kinds of FPM have been used, tested and often failed.

The solution is rotary lobe pumps equipped with PTFE or stainless steel rotors, dynamic o-rings from Chemraz 505, static o-rings from PTFE. As a rotor material, PTFE is often not possible with other rotary positive displacement pumps since it is a cold flowing material. The timing gear with a non-contacting rotor synchronization allows the use of PTFE for rotary lobe pumps. Chemical Industry Specialty Chemical Plant In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up. The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances. To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

The solution is rotary lobe pumps equipped with PTFE or stainless steel rotors, dynamic o-rings from Chemraz 505, static o-rings from PTFE. As a rotor material, PTFE is often not possible with other rotary positive displacement pumps since it is a cold flowing material. The timing gear with a non-contacting rotor synchronization allows the use of PTFE for rotary lobe pumps. Chemical Industry

In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up.

In a specialty chemical plant, sanitary lobe pumps were used to pump a mixture of water and crushed plastics material in various sizes with abrasive characteristic for a protection foil production line. The lobe pumps were used in the front end of the process and the high wear rate required constant rebuilding of the pump units. Rotors and pump casings were constantly shipped to the manufacturer for re-machining. In addition, tight tolerances in the area where the shaft extended to the front cover caused accumulated material, closed clearances, and increased friction, creating high, problematic temperature build-up.

The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances.

The sanitary lobe pumps were replaced with a non-sanitary lobe pump design. To reduce the life cycle cost, the new units are equipped with axial and radial pump casing protection plate, eliminating any re-machining. Also, a set of protection plates only costs a fraction of a new stainless steel pump casing. When the customer installs new protection plates and rotors, the pump unit is back to factory tolerances.

To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

To deal with material build up, a lobe pump design with a flat front protection plate was chosen. A heavy duty design was chosen with shafts not extending into the front cover area, eliminating material and temperature build-up. The customer increased safety and reduced life cycle cost.

troubleshooting rotary vane vacuum pump

troubleshooting rotary vane vacuum pump

The installed rotor of a rotary vane vacuum pump is tangent to the stator fixed surface inside the pump eccentric, two or more rotary vanes slide in the rotor slot and contact with the inner wall of the stator, which makes the pump chamber divided into several variable volumes.

A rotary vane vacuum pump can remove the dry gas from the sealed container. It can remove a certain amount of condensable gas if it has gas ballast device. However, it is not appropriate to remove some gases that are highly oxygenated, corrosive to metals, react chemically to pump oil, and contain particulate dust.

It means the highest oil temperature measured near a low level exhaust valve exceed the specified value of the operating instruction. The pump oil viscosity sharply drops because temperature of the pump elevated, which makes the saturated vapor pressure on the pump oil and the limit pressure in the pump increase and the pumping efficiency decrease.

Oil leakage occurs to the sealing surface of shaft seal, oil box and pump parts, oil drain plug, oil label, oil hole plug, through hole connection between the stator components and bearing and gas ballast valve, which is caused by aging of sealing parts, improper installation, damage and failure, uneven surface, impurities, rough and loose casting. If stopping pump return oil, the oil will enter the gas ballast valve. Close the gas ballast valve, otherwise oil leaks. When making the rubber mat, it should be sure to use oil resistant rubber, and be shaped according to the original design. If the sealing surface is too big, it will cause oil leakage.

Water leakage occurs to some places, including pipe head, water jacket sealing surface, the drain hole screw plug and drain valve, etc. Water jacket drilling, casting defects, freezing crack, may lead to water leakage as well.

Continuous working for a long period of time will lead to excessive maximum power, mainly reflected in the inlet and exhaust pressure are too high, temperature of the pump is too high, and the clearance of rotary vanes is too small, high voltage and pump liquid back into the pump. Excessive maximum power will lead to the motor damage. Continuous operation near the maximum power should be avoided as far as possible. If there are some sediments, it should be regularly cleaned.

It can be caused by external leakage, internal leakage, oil hole blockage, poor pump oil quality or pollution deterioration, water vapor and other condensable substances, instrument distortion and pump operation is not normal.

If external leakage is too much, white steam can be seen at the exhaust vent. There are a lot of bubbles in the oil mark and low level exhaust valve. The exhaust pressure is felt when a hand is put on the exhaust vent, the power will increase as well. At this moment, first check whether the gas ballast valve has been closed. In case of external leakage, check the pump port, pipe, valve and container one by one. In addition, seal failure of the outer shaft no oil in the oil cup, oil hole leakage can cause external leakage as well. Internal leakage can cause by the movement gap between the pump, exhaust valve plane, exhaust valve sealing surface, internal shaft seals, pump cover plates, air intake pipe, sealing parts of the valve will cause to wear, corrosion, and bite, which makes the operation gap increase. When the fuel tank is well sealed, if the hand feels sucked on the vent, the exhaust valve may fail.

If pump oil is clean and long storage unused, the gas ballast valve can be open to purify the water vapor in the pump. If pump oil is yellow, white or have been emulsified, fully open the air ballast, adjust air quantity and purify operation. When necessary can put the right amount of gas into the pump mouth operation, which can speed up the purification process. If the pump oil is mixed with other volatile gas or liquid, it is necessary to change oil timely and clean the oil tank. Some vacuum pumps, the pump fluid will be deposited in the interstage airway. In order to achieve a good oil exchanges effect, try to discharge the sedimentary pump fluid.

Ultimate pressure is measured by compression mercury vacuum gauge, when it is measured with a calibrated thermocouple gauge, the measured value increases. It is recommended to reserve a parallel calibration regulator for comparison in case of suspected regulatory pollution distortion. Ultimate pressure increasing will make the extraction efficiency decrease in high vacuum period as well as ultimate fully pressure increase. The above can be used to judge, check and deal with failures of reduced pumping efficiency and increased ultimate fully pressure.

There are many reasons for vacuum pumps making noise, such as the structure design of vacuum pump, the motor and pump bearing making noise, rotary vanes not smooth, large intake volume, loose parts in the vacuum pump and unequal installation making vibration.

There are many factors that influence the oil spouts of vacuum pump, which are the size, position and sealing condition of the oil box return hole as well as the design and installation of the oil baffle plate. The Mist eliminator, oil baffle cap and oil and gas separator of exhaust port and the height of the oil level and the size of the oil intake influences the oil spouts of vacuum pump as well.

compression issues: causes and remedies

compression issues: causes and remedies

Usually, when evaluating a new tablet press, one of the first questions asked concerns the number of compression stations. The number of tablets that can be produced with a press is a crucial parameter for every manufacturer of solid dosage forms. And, for single rotary tablet presses, this is a number that can easily be calculated by multiplying the number of stations by the rotation speed and the running time in minutes. For example, a press with 25 stations running with 120 revolutions per minute produces 180,000 tablets per hour.

In an actual pharmaceutical manufacturing environment, however, the number of stations plays a somewhat less important role regarding the number of tablets that can be produced with a particular press. The majority of pharmaceutical tablets are not produced at the presss maximum compression speed because it is not possible to produce tablets of acceptable quality at high rotation speeds. Defects such as capping, sticking and lamination occur, and the tablets become subject to weight and content variations. In many cases, reducing the rotation speed of the press makes it possible to avoid these problems. As such, the simple relationship between reduced rotation speed and fewer out-of-specification tablets will be observed.

Usually, eccentric presses or small, rotary tablet presses operated at slow speeds are used when developing tablets. Often, the development process focuses on optimizing tablet characteristics such as hardness, disintegration time, stability and/or friability. Less attention is paid to the tableting process itself, as very different operating parameters will be used during full-scale production. Typically, tableting problems only occur during scale-up and when using high-speed production-scale machines. This phenomenon will be explained below using tablet capping as an example.

The extent to which a tablet is prone to capping depends on the deformation behaviour of individual components. If materials are used that deform plastically or undergo brittle fracture, the risk is low. But, if the tablet formulation contains substances that deform elastically or demonstrate viscoelastic deformation, there is a high risk of capping, particularly with rapidly applied loads. The situation is exacerbated if the active pharmaceutical ingredient (API) itself shows this behaviour and has to be incorporated into the tablet in high concentrations. In almost all other cases, capping can be avoided completely by the appropriate choice of pharmaceutical excipients. However, capping will always occur if, following compression, more elastic energy is accumulated in the tablet than its inner structure can absorb.

Apart form the choice of excipients, the processes that precede tableting also influence the tablets tendency to cap. In the case of direct compression, only the compression properties of the substances used will define the extent of the capping potential. Another problem associated with direct compression is the higher proportion of fines, which also increase the tendency to cap. Wet granulation, by contrast, enables capping to be minimized, according to how evenly the binder is distributed during granulation. Therefore, granulates that have been produced by spray granulation generally cap less than those produced using an intensive mixer granulator.

Another cause of capping is entrapped air that has been compressed during main compression and eventually shatters the tablet as a result of perfect elastic behaviour. The more open-pored a material is usually discernible by its low bulk density the more air it contains. The majority of this air should be removed during pre-compression. Yet, the problem here is that with faster tableting speeds, less time is available. Different tablet press manufacturers have developed a variety of concepts to improve this situation; as such, the speed of the press can be increased by up to four times for critical formulations [1].

If the diameter of the tablet press rotor is Xcm, then the die covers a distance of S = X * cm during one rotation. The circumferential speed (V), measured in m/s, can be calculated as follows: V = S * rpm/60 (with rpm being the number of rotations per minute). The division by 60 is necessary to define the speed in m/s.

If a press is operated at a lower rotation speed to avoid problems with capping, this can be equated to a reduction of the circumferential speed. In other words, capping can be prevented if the press runs below a certain circumferential speed. Thus, if a formulation has a strong tendency to cap, the number of tablets produced per hour cannot be improved by simply increasing the number of pressing stations. Only a reduction in the distance between the dies, which is offered by several manufacturers, can improve the output (Table I) [2,3].

Press A is the reference. Press B is identical, but has a bigger rotor. Press C has the same rotor as press B, but the number of press stations has been increased by reducing the distance between the single dies [2,3]. Assuming that the maximum circumferential speed is 2.5 m/s owing to capping, this results in the fact that the larger presses (B and C) have to operate at a reduced rotation speed compared with Press A. As a result of linear correlation, in the case of press B, this counteracts the effect of the increased number of pressing stations. The higher output achieved with Press C is the result of the reduced distance between the single dies.

Usually, it is not possible to change the formulation during scale-up from R&D to production to reduce the tendency to cap. And, in most cases, only minor adjustments can be made to optimize upstream processes. Apart from reducing the number of turret rotations, and therefore the circumferential speed, only two other options remain. On one hand, punches with larger heads can be used. And, on the other hand, it is possible to retract the upper punch more slowly following main compression. As a result, in many cases, the stored energy can be transferred to the upper punch without the tablets being destroyed by capping.

Each tableting process aims to produce tablets with a constant weight. Yet, as a result of variations in the density of the feed material and partial or incomplete filling of the dies, there are always weight variations (the relevant pharmacopoeia specify acceptable weight variation levels). The threat of weight variation is minimized if the feed material is produced by granulating or compaction; ideally, the composition of the feed material should be determined down to single particle characteristics. But, if the feed material has a wide particle size and/or density distribution, the risk of segregation and subsequent weight and tablet content variation is high. This danger can be minimized by mechanically decoupling the press and the feed material to minimize the risk of segregation. Furthermore, allowing the feed material to free fall between unit operations should be avoided.

Similar to capping, content variations are more pronounced at higher press speeds: with increasing rotation rates, the ruling speed also increases, which means that the period that the die remains under the filling unit decreases. This means that with increasing press speeds, greater demands must be made on the flowability of the feed material. An alternative approach would be to impose a maximum circumferential speed for each powder flowability rate to guarantee uniform die filling.

There are different ways to characterize flowability, including the Hausner factor or by determining the angle of repose, and one of the key tasks of developing mainstream processes must be to significantly improve the flowability of the feed material. A detailed consideration would go beyond the scope of this article; but, generally, every effort should be made to granulate the material with the greatest possible mechanical energy while minimizing the formation of lumps and caking. This material must be milled again during downstream processing, which results in an increased amount of fines and poor flowability.

During scale-up from R&D to production, upstream processes can only normally be optimized within very narrow limits. But, often, the situation can be improved by using a forced filling approach. If the lower punch is retracted before the die reaches the filling unit area, the material enters the die as a result of gravity. With forced filling, however, the lower punch is flush with the die table. The lower punch is then pulled into its target position below the filling unit. The material is sucked into the die because of the resulting vacuum, which makes it possible to use high pressing speeds even if the material doesnt flow optimally.

The number of tablets that can be produced with a tablet press per time unit depends only partly on the number of existing pressing stations. In most cases, the operating speed of the press has a much greater influence. This speed depends on the design of the press and particularly on the characteristics of the feed material. The quality of the feed material is strongly determined by its composition and the upstream processes used to prepare it for tableting.

The number of tablets that can be produced with a press is a crucial parameter for every manufacturer of solid dosage forms. And, for single rotary tablet presses, this is a number that can easily be calculated by multiplying the number of stations by the rotation speed and the running time in minutes. For example, a press with 25 stations running with 120 revolutions per minute produces 180,000 tablets per hour.

GEA is one of the worlds largest systems suppliers for the food, beverage and pharmaceutical sectors. The international industrial technology group specializes in machinery and plants as well as advanced process technology, components and comprehensive services. With more than 18,000 employees, the group generated revenue of more than EUR 4.6 billion in fiscal year 2020. A major focus is on continuously enhancing the sustainability and efficiency of customers production processes. GEA plants, processes and components help achieve significant reductions in carbon emissions, plastic use and food waste in production worldwide. In this way, GEA makes a decisive contribution toward a sustainable future, fully in line with its corporate philosophy of engineering for a better world.

troubleshooting | air conditioning and refrigeration | daikin global

troubleshooting | air conditioning and refrigeration | daikin global

Information is provided here for resolving trouble in operation centering on residential-use air conditioners. Although all situations are not covered in this section, answers to the most frequently asked areas are provided. To save time and trouble, we recommend that you refer first to this page.

When dry or cooling operation is activated with the auto fan speed setting set to ON, the SMELL PROOF operation starts and removes stagnant odor from the indoor unit before air is discharged. Therefore, the unit does not discharge air immediately after the operation starts. Please wait for about 30 to 40 seconds.

When the room temperature reaches the set temperature, the air conditioner operates in breeze mode to prevent excessive cooling or heating. When the room temperature decreases or increases from the set temperature, the breeze mode is cancelled and the air flow volume increases. When the room temperature is stable and remains near the set temperature, the air flow volume may increase and decrease repeatedly.

This is not a malfunction of the air conditioner. When the ON timer is set, operation starts up to 1 hour before the time set to reach the setpoint. If the remote controller is operated during this time, the operation automatically stops. Restart operation using the remote controller.

When the auto filter cleaning setting is ON (default), the air conditioning operation stops after 24 hours of air conditioning operation (cooling mode, dehumidifying mode, heating mode, air purifying mode, or ventilation mode) to activate the automatic filter cleaning operation. After the cleaning operation is complete, the air conditioning operation resumes.

When the room is completely closed and the ventilation fan is operating or when strong winds are blowing outside, outdoor air can enter the drain hose and cause a bubbling sound. This phenomenon tends to occur in a well-sealed house or apartment.

Do not use a commercial cleaning agent. Commercial cleaners may cause adverse effects on the resin parts of the heat exchanger or other internal components. In the worst case, problems such as water leaks can occur.

We recommend cleaning the air filters every 2 weeks. Wash the filters with water or clean them with a vacuum cleaner. (See the manual for details.) For heavy soiling, wash the filters with a neutral detergent diluted with tepid water and let the filters dry in a shady place.

To prevent damage to the air conditioner when humidifying or ventilation operation stops, filter cleaning operation starts after the humidifying fan stops operating. Thus, the filter cleaning operation time becomes longer. Please wait for 14 minutes.

Check if the unit is operating without some of the following parts: pre-filter, air discharge grille, dust collecting filter, humidifying filter air, humidifying tray, or water tank. If any of those parts are not installed, the fan may stop operating in order to prevent damage to electrical parts. If any of those parts are not installed, unplug the power cord, install the parts correctly, and then operate the unit.

The hissing sound is produced by the Streamer unit during Streamer discharge. The sound may become quieter or changes to a crackling sound, buzzing sound or slurping sound depending on usage conditions. Those sounds do not indicate a malfunction. If the sound disturbs you, try placing the unit at a different location.

If water is left in the water tank for an extended period of time, bacteria can grow and change the color of water. Replace the water in the water tank on a regular basis and clean the water tank and humidifying tray.

Discard water from the water tank and humidifying tray, clean the product, and let the inside of the unit dry thoroughly in the shade. Cover the product with a plastic bag to prevent dust from entering the air outlet, and store the unit in a dry place. Keep the unit upright during storage.

Before using the product only for air purification, discard water from the water tank and humidifying tray, clean the product, and let the inside of the unit dry thoroughly in the shade. The product can operate for air purification even if the water tank is empty.

Even when the unit operates only for air purification, air draft causes natural evaporation of water and slight humidification results. Thus, the water level in the water tank decreases. If the product is used only for air purification, discard water from the water tank and humidifying tray before operating.

Dismount the outlet grille, water tank, humidifying tray, etc., and remove the entered object. Note that the active plasma ionizer unit (located on the side opposite from the water tank) cannot be disassembled by the user. Contact the place of purchase.

troubleshooting typical screen printing problems | systematic automation

troubleshooting typical screen printing problems | systematic automation

The following are suggestions for common screen printing problems that can occur with most models. These are geared toward using UV cure inks. For more suggestions, or application questions, it is best to call you ink supplier or manufacturer.

Great customer service is part of our culture here at Systematic Automation. Were ready and happy to help you with your questions, and assist you in selecting the right machine for your specific application. Were also happy to provide you with a customized quote. Just get in touch - wed love to hear from you.

maytag dryer troubleshooting: maytag dryer is not drying, not heating

maytag dryer troubleshooting: maytag dryer is not drying, not heating

Find out what the cause of failure drying machine will help table of troubleshooting. In front of all descriptions of problem, there are cause and possible solution. Your dryer is not working? Or maybe some of its functions are not available, and it is not heating properly? Whenever your Maytag dryer not drying, you should perform troubleshooting: our guide is here to help you with that.

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