tray dryer industrial applications

how a simple innovation changes the tablets future

how a simple innovation changes the tablets future

A range of technologies are used for food drying which include tray and tunnel dryers, spray, roller and freeze dryers. Tray dryers are quite suitable for drying wet chemicals, powders and crude drugs.

A simple tray dryer is a box-shaped cabinet in which a series of trays are inserted on shelves one on top of the other. Unlike an oven which perhaps has a heater in the base of the cabinet or walls, heat is supplied to a tray dryer by circulating air that has been heated either electrically or by some other means. One or more fans circulate the hot air over the trays.

The best tray dryers are those in which the air flow to the trays can be controlled. The materials to be dried are spread out on top of the trays which may be lined with paper. To shorten cleaning time and prevent contamination, disposable papers are used as tray liners. The trays are often supported on tiers made of wire mesh or perforated steel.

In the latest tray dryers, uniform temperature is achieved throughout a well-insulated cabinet by the use of strategically placed deflectors, which direct the air from one tray to pass over the tray above in the opposite direction. Air flowing in alternate directions over the trays ensures uniformity of flow and helps to keep the temperature uniform. The air may also be reheated before it passes from one shelf to the next. Air that passes each shelf loses a certain amount of heat (the latent heat of vaporisation of the water that is expelled from the solid material).

Hot air therefore continuously circulates in a tray dryer, and the heat of the air removes the moisture from the material in the trays by forced convection. At the same time, moist air is expelled from the cabinet to vent.

Drying is commonly used after wet granulation. This is the process in which a tablet mix is turned in to a paste with water and then broken up in to granules. Granulation can increase the consistency and the flowability of material in the tableting process.

There are several variants of tray dryer, ranging from simple manual systems ideal for batch processes through semi-automatic and automatic systems for processing large quantities. The basic principles are the same in each case, as follows.

A vacuum tray dryer is used mainly for drying of high grade, temperature and oxygen sensitive products. It is suitable for drying hygroscopic substances, which are dried to a very low residual moisture content. Vacuum drying cabinets are often the only means of drying lumpy, glutinous products or products of low porosity.

When the dryer is loaded with materials it is first heated at atmospheric pressure. Only after all individual product trays reach the same temperature is the cabinet is evacuated and drying commenced. The initial heating phase is necessary to enable a uniform temperature and drying conditions to be established throughout the cabinet. During the main drying phase the vacuum is in the range of 40 to 80 mbar abs. This may be reduced to a few mbar in the final stages of drying.

Heating temperatures within a vacuum dryer can be much higher than an air dryer, and are often in the range between 800C and 1100C. Some systems allow automatic programming of both temperature and vacuum profiles. On completion of the drying, the product can be cooled by circulating of cooling water through the heating plates.

solids drying: basics and applications - chemical engineering | page 1

solids drying: basics and applications - chemical engineering | page 1

Adjustment and control of moisture levels in solid materials through drying is a critical process in the manufacture of many types of chemical products. As a unit operation, drying solid materials is one of the most common and important in the chemical process industries (CPI), since it is used in practically every plant and facility that manufactures or handles solid materials, in the form of powders and granules.

The effectiveness of drying processes can have a large impact on product quality and process efficiency in the CPI. For example, in the pharmaceutical industry, where drying normally occurs as a batch process, drying is a key manufacturing step. The drying process can impact subsequent manufacturing steps, including tableting or encapsulation and can influence critical quality attributes of the final dosage form.

Apart from the obvious requirement of drying solids for a subsequent operation, drying may also be carried out to improve handling characteristics, as in bulk powder filling and other operations involving powder flow; and to stabilize moisture-sensitive materials, such as pharmaceuticals.

Drying may be defined as the vaporization and removal of water or other liquids from a solution, suspension, or other solid-liquid mixture to form a dry solid. It is a complicated process that involves simultaneous heat and mass transfer, accompanied by physicochemical transformations. Drying occurs as a result of the vaporization of liquid by supplying heat to wet feedstock, granules, filter cakes and so on. Based on the mechanism of heat transfer that is employed, drying is categorized into direct (convection), indirect or contact (conduction), radiant (radiation) and dielectric or microwave (radio frequency) drying.

Heat transfer and mass transfer are critical aspects in drying processes. Heat is transferred to the product to evaporate liquid, and mass is transferred as a vapor into the surrounding gas. The drying rate is determined by the set of factors that affect heat and mass transfer. Solids drying is generally understood to follow two distinct drying zones, known as the constant-rate period and the falling-rate period. The two zones are demarcated by a break point called the critical moisture content.

In a typical graph of moisture content versus drying rate and moisture content versus time (Figure 1), section AB represents the constant-rate period. In that zone, moisture is considered to be evaporating from a saturated surface at a rate governed by diffusion from the surface through the stationary air film that is in contact with it. This period depends on the air temperature, humidity and speed of moisture to the surface, which in turn determine the temperature of the saturated surface. During the constant rate period, liquid must be transported to the surface at a rate sufficient to maintain saturation.

At the end of the constant rate period, (point B, Figure 1), a break in the drying curve occurs. This point is called the critical moisture content, and a linear fall in the drying rate occurs with further drying. This section, segment BC, is called the first falling-rate period. As drying proceeds, moisture reaches the surface at a decreasing rate and the mechanism that controls its transfer will influence the rate of drying. Since the surface is no longer saturated, it will tend to rise above the wet bulb temperature. This section, represented by segment CD in Figure 1 is called the second falling-rate period, and is controlled by vapor diffusion. Movement of liquid may occur by diffusion under the concentration gradient created by the depletion of water at the surface. The gradient can be caused by evaporation, or as a result of capillary forces, or through a cycle of vaporization and condensation, or by osmotic effects.

The capacity of the air (gas) stream to absorb and carry away moisture determines the drying rate and establishes the duration of the drying cycle. The two elements essential to this process are inlet air temperature and air flowrate. The higher the temperature of the drying air, the greater its vapor holding capacity. Since the temperature of the wet granules in a hot gas depends on the rate of evaporation, the key to analyzing the drying process is psychrometry, defined as the study of the relationships between the material and energy balances of water vapor and air mixture.

There are a number of approaches to determine the end of the drying process. The most common one is to construct a drying curve by taking samples during different stages of drying cycle against the drying time and establish a drying curve. When the drying is complete, the product temperature will start to increase, indicating the completion of drying at a specific, desired product-moisture content. Karl Fischer titration and loss on drying (LOD) moisture analyzers are also routinely used in batch processes. The water vapor sorption isotherms are measured using a gravimetric moisture-sorption apparatus with vacuum-drying capability.

For measuring moisture content in grain, wood, food, textiles, pulp, paper, chemicals, mortar, soil, coffee, jute, tobacco, rice and concrete, electrical-resistance-type meters are used. This type of instrument operates on the principle of electrical resistance, which varies minutely in accordance with the moisture content of the item measured. Dielectric moisture meters are also used. They rely on surface contact with a flat plate electrode that does not penetrate the product.

For measuring moisture content in paper rolls or stacks of paper, advanced methods include the use of the radio frequency (RF) capacitance method. This type of instrument measures the loss, or change, in RF dielectric constant, which is affected by the presence or absence of moisture.

Adiabatic dryers are the type where the solids are dried by direct contact with gases, usually forced air. With these dryers, moisture is on the surface of the solid. Non-adiabatic dryers involve situations where a dryer does not use heated air or other gases to provide the energy required for the drying process

Non-adiabatic dryers (contact dryers) involve an indirect method of removal of a liquid phase from the solid material through the application of heat, such that the heat-transfer medium is separated from the product to be dried by a metal wall. Heat transfer to the product is predominantly by conduction through the metal wall and the impeller. Therefore, these units are also called conductive dryers.

Although more than 85% of the industrial dryers are of the convective type, contact dryers offer higher thermal efficiency and have economic and environmental advantages over convective dryers. Table 1 compares direct and indirect dryers, while Table 2 shows the classification of dryers based on various criteria.

Tray dryers. This dryer type operates by passing hot air over the surface of a wet solid that is spread over trays arranged in racks. Tray dryers are the simplest and least-expensive dryer type. This type is most widely used in the food and pharmaceutical industries. The chief advantage of tray dryers, apart from their low initial cost, is their versatility. With the exception of dusty solids, materials of almost any other physical form may be dried. Drying times are typically long (usually 12 to 48 h).

Vacuum dryers. Vacuum dryers offer low-temperature drying of thermolabile materials or the recovery of solvents from a bed. Heat is usually supplied by passing steam or hot water through hollow shelves. Drying temperatures can be carefully controlled and, for the major part of the drying cycle, the solid material remains at the boiling point of the wetting substance. Drying times are typically long (usually 12 to 48 h).

Fluidized-bed dryers. A gas-fluidized bed may have the appearance of a boiling liquid. It has bubbles, which rise and appear to burst. The bubbles result in vigorous mixing. A preheated stream of air enters from the bottom of the product container holding the product to be dried and fluidizes it. The resultant mixture of solids and gas behave like a liquid, and thus the solids are said to be fluidized. The solid particles are continually caught up in eddies and fall back in a random boiling motion so that each fluidized particle is surrounded by the gas stream for efficient drying, granulation or coating purposes. In the process of fluidization, intense mixing occurs between the solids and air, resulting in uniform conditions of temperature, composition and particle size distribution throughout the bed.

Freeze dryers. Freeze-drying is an extreme form of vacuum drying in which the water or other solvent is frozen and drying takes place by subliming the solid phase. Freeze-drying is extensively used in two situations: (1) when high rates of decomposition occur during normal drying; and (2) with substances that can be dried at higher temperatures, and that are thereby changed in some way.

Microwave vacuum dryers. High-frequency radio waves with frequencies from 300 to 30,000 MHz are utilized in microwave drying (2,450 MHz is used in batch microwave processes). Combined microwave-convective drying has been used for a range of applications at both laboratory and industrial scales. The bulk heating effect of microwave radiation causes the solvent to vaporize in the pores of the material. Mass transfer is predominantly due to a pressure gradient established within the sample. The temperature of the solvent component is elevated above the air temperature by the microwave heat input, but at a low level, such that convective and evaporative cooling effects keep the equilibrium temperature below saturation. Such a drying regime is of particular interest for drying temperature-sensitive materials. Microwave-convective processing typically facilitates a 50% reduction in drying time, compared to vacuum drying.

Continuous dryers are mainly used in chemical and food industries, due to the large volume of product that needs to be processed. Most common are continuous fluid-bed dryers and spray dryers. There are other dryers, depending on the product, that can be used in certain industries for example, rotary dryers, drum dryers, kiln dryers, flash dryers, tunnel dryers and so on. Spray dryers are the most widely used in chemical, dairy, agrochemical, ceramic and pharmaceutical industries.

Spray dryer. The spray-drying process can be divided into four sections: atomization of the fluid, mixing of the droplets, drying, and, removal and collection of the dry particles (Figure 2). Atomization may be achieved by means of single-fluid or two-fluid nozzles, or by spinning-disk atomizers. The flow of the drying gas may be concurrent or countercurrent with respect to the movement of droplets. Good mixing of droplets and gas occurs, and the heat- and mass-transfer rates are high. In conjunction with the large interfacial area conferred by atomization, these factors give rise to very high evaporation rates. The residence time of a droplet in the dryer is only a few seconds (530 s). Since the material is at wet-bulb temperature for much of this time, high gas temperatures of 1,508 to 2,008C may be used, even with thermolabile materials. For these reasons, it is possible to dry complex vegetable extracts, such as coffee or digitalis, milk products, and other labile materials without significant loss of potency or flavor. The capital and running costs of spray dryers are high, but if the scale is sufficiently large, they may provide the cheapest method.

With increasing concern about environmental degradation, it is desirable to decrease energy consumption in all sectors. Drying has been reported to account for anywhere from 12 to 20% of the energy consumption in the industrial sector. Drying processes are one of the most energy-intensive unit operations in the CPI.

One measure of efficiency is the ratio of the minimum quantity of heat that will remove the required water to the energy actually provided for the process. Sensible heat can also be added to the minimum, as this added heat in the material often cannot be economically recovered. Other newer technologies have been developed, such as sonic drying, superheated steam, heat-pump-assisted drying and others.

Drying is an essential unit operation used in various process industries. The mechanism of drying is well understood as a two-stage process and depends on the drying medium and the moisture content of the product being dried.

Batch dryers are common in chemical and pharmaceutical industries, while continuous dryers are routinely used where large production is required. Since the cost of drying is a significant portion of the cost of manufacturing a product, improving efficiency or finding alternative drying routes is essential.

1. Sverine, Thrse, Mortier, F.C., De Beer, Thomas, Gernaey, Krist V., Vercruysse, Jurgen, et al. Mechanistic modelling of the drying behavior of single pharmaceutical granules, European Journal of Pharmaceutics and Biopharmaceutics 80, pp. 682689, 2012.

6. Raghavan, G.S.V., Rennie, T.J., Sunjka, P.S., Orsat, V., Phaphuangwittayakul, W. and Terdtoon, P., Overview of new techniques for drying biological materials, with emphasis on energy aspects, Brazilian Journal of Chemical Engineering, 22(2), pp. 195201, 2005.

Dilip M. Parikh is president of the pharmaceutical technology development and consulting group DPharma Group Inc. (Ellicott City, MD 21042; Email: [email protected]). As an industrial pharmacist, Parikh has more than 35 years of experience in product development, manufacturing, plant operations and process engineering at various major pharmaceutical companies in Canada and the U.S. Prior to staring DPharma Group, he held the position of vice president of operations and technology at Synthon Pharmaceuticals in North Carolina and vice president and general manager at Atlantic Pharmaceuticals Services in Maryland. He is the editor of Handbook of Pharmaceutical Granulation 3rd ed. He has authored several book chapters and articles on various pharmaceutical technologies, including quality by design, process assessment and contract manufacturing. He has been an invited speaker at scientific conferences worldwide on solid-dosage technologies development and manufacturing.

This publication contains text, graphics, images, and other content (collectively "Content"), which are for informational purposes only. Certain articles contain the author's personal recommendations only. RELIANCE ON ANY INFORMATION SUPPLIED IN THIS PUBLICATION IS SOLELY AT YOUR OWN RISK. 2021, Access Intelligence, LLC. All rights reserved. | Privacy Policy | Diversity Inclusion & Equity

tray dryers construction and working | engineering products info

tray dryers construction and working | engineering products info

Tray dryers are used to dry products in medicine manufacturing. It is the most reliable means of drying in wet-granulation method of drug production. With the wet-granulation method used often in the booming pharmaceutical industry, tray dryer exporters are also under heavy demand. Other industries where tray dryers are used include chemicals, textiles and paints. Before you consider buying one, you must understand the functioning of tray dryers.

Wet-granulation method is popular in medicine manufacturing because it is more likely to satisfy the various criteria of tablet compression. However, it does involve multiple steps that take a lot of time and effort. However, despite the time taken, it is still preferred because of its reliability in creating the right product.

Different types of dryers are used in this method to remove the moisture from solids, powders, and sheet. The are two types of dryers: direct dryers and indirect dryers. Direct dryers use convection method of heating the trays where direct contact with hot air is used to dry the product. In indirect dryers use conduction process and indirect contact with a hot object to create dryness.

Tray dryers are the most conventional method of drying. The simplest construction of a tray dryer is in the form of a cabinet with a heater at the base. The dryer is usually made of iron or steel with high insulation. The insulation is achieved by double walled panels with compressed fiber glass wool. The insulation is critical to reduce nay heat leakage. There are single or two doors. It also relies on a heavy duty locking mechanism. Gaskets form seals that reduce heat leakage.

The heater at the base is typically an industrial oven. The cabinet like construction contains different layers of trays. The trays, made of stainless steel, are mounted on wheeled trolleys. Small dryers can contain around 6, while large dryers may even have as many as 192 trays. The right construction is chosen as per requirements. A control panel board on the outside helps us to monitor and control the working of the dryer. The panel includes temperature controller, process timer, indicator and more.

The main industries for tray dryer exporters are pharmaceuticals. But it is also widely used wherever we need drying of wet material during processing or at raw material stage, such as the chemicals, F&B, dyes, and paint industry. The material to be dried is placed on the trays. The heat in the dryer is produced by the heater at the base. Other than the hot air generated by the oven, the other method is to have radiator coils that use steam for heat circulation. One can choose the heating method as per preferences and material to be dried.

During the heating process the material to be dried is spread out on the trays. The heated air is directed to flow in a circulation form. It flows over the material in the trays in a controlled flow. Trays can have a solid, perforated or wire mesh base. A paper lining could be used to reduce chances of contamination through contact with the tray.

The efficiency of the dryer depends on circulation and recirculation of the hot air. Apart from a regular supply and presence of heated air, it also depends on supply of fresh air. The fresh is combined with the heated air in fixed proportion for an efficient system. Such regulated drying is also important to ensure to ensure uniform drying in the dryer where the bottommost tray drys at the same pace as the trays placed on top. Apart from the double-walled construction, insulation is also achieved by heating coils and fans.

A simple Internet search will five you multiple options in tray dryer manufacturers and exporters. Locality of the company can be a factor if it does not offer to deliver to your address. Some sites may also give you feedback from genuine users. You can also check out the website of the company for details.

Check the production capacity of the firm, particularly if they build dryers of the dimensions you are looking for. Other factors include pricing, tray size, total capacity, material and the heating method employed. Find out the industry standard and evaluate all factors as per this standard before picking the right tray dryer exporter.

tray dryer, industrial tray dryer, batch tray dryer, tray dryer machine, high temperature oven, electric tray oven, vertical door oven manufacturer, exporter jas enterprises

tray dryer, industrial tray dryer, batch tray dryer, tray dryer machine, high temperature oven, electric tray oven, vertical door oven manufacturer, exporter jas enterprises

At Jas enterprise, Tray Dryer that is adequately designed by our designers and adroit personnel who take every care in the fabrication of a durable and highly efficient range of machines. Available in various models such as 12 trays, 24 trays, 48 trays, 96 trays, these are high in performance and low on maintenance. The significant traits of our exclusive array include the following: Models: 12 trays, 24 trays, 48 trays, 96 trays and 192 trays construction.

We manufacture a wide range of Tray Dryer/ Drying Oven that is widely used for heating, ageing, drying and many more purpose. Our range of these ovens is designed for parallel placement of the material that results in increase in production and saves batch timing by convenient loading and unloading. This types of Tray Dryer is available with external temperature control panel, and high temperature can also be fabricated. Owing to the superior quality of our products, our range of these products is widely demanded in the market. Moreover, these ovens are available in various sizes and models to choose from.

The dryers are made of trays held in a cabinet which is connected to a source of air heated by electric. The air temperature is controlled by a thermostat which is normally set between 50 and 300 C. The air enters the bottom of the chamber below the trays and then rises, through the trays of food being dried, and exits from an opening in the top of the chamber. In the Practical Action systems the trays are designed to force the air to follow a longer zigzag route which increases the air/food contact time and thus improve its efficiency. This system also reduces back pressure which means that fans are used.

Tray Dryers are ideally suitable for drying chilies, spices, potato chips, onions, fish, garlic, grapes, cashew nuts, confectionery, macaroni, vermicelli, noodles etc. It is also for used for drying pharmaceuticals, chemicals, powders, granules, plastic granules etc. Heating is either by electric or steam or both combined. Various models are designed & manufacture to suit customer requirements. Custom-built models can be quoted on request.

The external frame work is made of thick gauge M. S plates both the exterior made of thick gauge CRCA sheets or AISI 304 sheets. in between the space, resin bonded special quality fiber glass heat insulation slabs are provided. safety guards for fan blade & heaters are provided. The interiors is painted with heat resistant aluminum paint. The exterior is spray painted with automotive, Inner Chamber - CRCA or AISI 304, Outer Chamber - CRCA or AISI 304.Fan & Motor : According to models doors are provided with smooth moving hinges, latch catch & sealing gaskets. Well balanced large propeller type fan (S) fitted inside the chamber with suitable shaft & dual bearing with Electric motor (S) drive.Heaters : 'U' type tubular heaters are provided inside the chamber for maximum heat transfer. Steam heated models are fitted with finned type steam radiators.Controls Panel : Control Panel box consists of contactor assembly, On & Off switch, Digital Controller neon lamps, operating push buttons are incorporated in the control Box. Damper : Adjustable exhaust Damper with an arrangement for pre-filtration, in the air inlet.Optional : GMP models / complete S.S unit. Trolleys & Trays supplied as per requirement. Microprocessor based temp. Control with printer interface (Centronic PC interface with RS 232 CPC / RS-485 for networking of controllers. Profile controller for Ramp / Soak cyclic applications.Safety Features : Built-in temp. deviation visual alarm. Safety thermostat for over shoot temp. cut off circuit to cut off the whole systems in case of malfunction. (only applicable to Microprocessor based models). Steam Heated Models : These are provided with finned tubular steam coils instead of /in addition to heaters, along with solenoid valve.

Jas Enterprise (An ISO 9001:2015 Certified Company)B-326, Sumel business park 7, Opposite Soni Ni Chawl BRTS Bus Stand, National Highway No 8, Near Rakhial Flyover, RakhialAhmedabad, Gujarat, IndiaMobile : (91) 94260 88680 Phone : (91) Email : [email protected]

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Due to continuous improvements, we reserve the rights to alter and/or amend dimensions/design without prior notice.The Figure for capacities given are for guideline only may very force case to case and depending many factors.

Copyright - Jas Enterprises.(An ISO 9001:2015 Certified Company). All Rights Reserved (Terms of Use)Developed and Managed by Jas enterpriseThis document was last modified on: by Sumatilal Sheth ([email protected])

industrial dehydrators

industrial dehydrators

Many products that normally require cart rotation in a dry can now be batch-dried in the Super McKenzie - optimal results with minimal oversight. This dehydrator is quite a different beast than the regular McKenzie tunnel: the redesigned drying chamber is now slighter wider and slightly shorter, in order to best channel large quantities of hot air hot air that circulates first in one direction, then in a reverse flow. We submit that hot air flowing in two directions is better than hot air that just flows in one direction. Its better in terms of improved product flavor, texture, color, and product uniformity. And for our clients doing large-scale dehydrating its better for the bottom line, period.

vacuum tray dryer installation, operational and performance qualification pharmaceutical updates

vacuum tray dryer installation, operational and performance qualification pharmaceutical updates

Pharmaceutical Updates was started to share knowledge among the pharma professionals & it will become helpful to the pharma Professionals. The author of pharmaceutical updates is Chandrasekhar panda who is having more than 13 years of Experience in Pharmaceutical Quality Assurance department and he has worked in Pharma Companies like Cipla, USV & Aurobindo Pharma Limited.

Vacuum Tray Dryer is a static type of dryer used in various industries under vacuum atmosphere to dry temperature sensitive materials as well as pharmaceutical and allied products. It gives complete drying and vaporization of moisture of the product. We at Bhagwati Pharma are manufacturer of Vacuum Tray Dryer. The vacuum tray dryers are been customized according to the clients specification and the available capacities ranges from 6 to 96 trays per batch.

Vacuum Tray Dryer works on the principle of conduction considering the vacuum conditions. There are several shelves placed under which products are placed. Top shelves gives proper heating and helps to prevent dried powder from escaping into the solvent extraction system. Baffles are been placed between the shelves. It contains an inlet and outlet nozzle both are connected to its own header throughout its own nozzle.

what are the types and applications of industrial drying ovens - armature coil equipment blog

what are the types and applications of industrial drying ovens - armature coil equipment blog

As the name suggests, industrial drying ovens are used for the withdrawal of moisture content from a substrate of a product. These ovens are highly popular to conduct various laboratory or industrial drying/ curing experiments.

Drying ovens are useful in various industrial applications such as incubation, sterilization of different products, evaporation (partial or complete), temperature testing, etc. These ovens are designed for exceptional heat distribution and drying. Delicate items like electronic chips or chemicals can get adversely affected if the drying is way too quick or too slow. Based on the size of your product or nature of the application, you can get drying ovens of different shapes, sizes, and capacities.

All these applications and many more stand as testimonials to the fact that industrial ovens are versatile and immensely useful in various sectors. With proper maintenance, these ovens can serve any industry for a long time.

Scott Heran has been part of the business since he was young and attending industry association conventions with his parents Bob and Jean since he was eight years old.Scott has worked in a sales capacity at ACE for over 20 years. Scott graduated from John Carroll University. Married to Teresa, he is the proud father of two children and two grandchildren.

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