trommel screen angle

building a trommel screen | conscious compost

building a trommel screen | conscious compost

This do-it-yourself compost sifter pairs nicely with a community-scale composting operation found at community gardens and farms. For a basic primer on aerated static pile composting check out my posts Aerated Static Pile Composting, Design & Build of Solar Powered Aerated Compost 3-Bin, and Supplies for a Basic Aerated Static Pile Setup.

Ive worked at a number of scales in the composting industry, including Fleet Manager for a large mulch and compost producer where I maintained the repairs for over $8 million in equipment (tub grinders, trommels, wheel loaders, semi trucks, etc.). Additionally, I spent my youth around farms and industrial machinery so designing and building this trommel came with fewer road blocks than others might have. Thats why Ive put this article together, to help the gardens and micro-enterprises develop a sifter, more specifically a trommel that fits your needs.

Ive wanted to build a trommel since I first strained my back screening compost over a sheet of hardware cloth. In many gardens screening or sifting is the overlooked part of the equation. Id spend hours over the course of a growing season making wonderful compost, but when it came time to sift compost for the garden I didnt have a good solution.

Equipment manufacturers in the compost industry cater to medium and large scale compost and soil producers. This makes good sense since the economics of composting generally requires large equipment. Granted there are smaller machines, such as the Sittler, that are made for landscaping services, soil blending businesses, farms, and so on, but they can carry a price tag that is difficult for a small start-up.

I started by researching DIY trommels and collected notes on design considerations. Having managed a fleet of equipment which included (8) 40 foot long trommels I knew that this project would be cutting out most of the nice features of trommels used in the industry. No conveyors, no input hopper, no brush to clean the screen and definitely no powder coated steel.

Popular mechanics ran a great article on building a trommel. I recommend you read it if youre serious about building one. That article also referred to some YouTubers (David Waltmans version and Geoff Babcocks version) with their iterations of trommels. I pulled screenshots of all the designs I liked and noted how certain areas were handled. I also looked at several videos I had of a Jet worm harvester to figure out a good rpm.

The design of the trommel drum is the most challenging part of the design/build process. The cylinder/drum/trommel is the part that does the work. It needs to be suspended in the frame while also having as little rolling friction as possible. Since it is going to be tilted it needs to be held in place to prevent it from sliding out as it rolls.

For my purposes I wanted the machine to have easily replaceable screens. I had two ideas for doing this and chose a method that I had seen in the past. I found a make a clamp kit online. The kit comes with pipe clamps and 50 feet of stainless steel banding. I used these to cut custom length pipe clamps which wrap around the screen and clamp the screen onto the aluminum ring.

Since the mesh does not act as structure (in some designs the hardware cloth is used to support itself) I needed to figure out a way to create a roundish structure without special metal fabricating equipment. To make the trommel round I went with the obvious solution, bike rims. I used the bike rims to fit 3 inch wide aluminum bands to the inside of the rims.

I used 27 bike rims that I picked up from a non-profit bike shop. If you look for rims made by Araya which were prevalent on late 70s through 80s road bikes youll be good. My trommel has five 27 Araya rims. They are close to the same inner diameter.

To bend the aluminum bands I used two 4x4s in the voids of two CMU blocks. This was a total guessing game. I just bent the metal a small amount at a time until I got a slow arc. Then repeated until it was almost a ring. I used a hack saw to trim the ring down to size.

I drilled through the rim and into the aluminum bands and used low profile bolt heads to bolt the two together. The 3 inch wide band creates a flange on both sides of the rim. This gives space to mount the screen. It also gives a place to put support wheels. The bike rim gives roundness and prevents the trommel from sliding off.

The rings are connected to four aluminum angles that run the full length of the screen. To help the screen do a better job of screening material I used 1 angle aluminum to carry material up the screen and drop it as the drum rotates.

The trommel is the core of the machine. I designed around it. I knew I would be using hardware cloth as my screen. They come in three widths at my local hardware store, 2 feet, 3 feet and 4 feet. The width of the screen informs the length of the trommel, which tells me which length lumber I should use for the frame.

To reduce wood waste and save time, I designed the frame to use dimensions that come standard from the lumber yard. I went with a low height, with the intention of using plastic tubs under the screen. Some gardens may want to fit a wheelbarrow or gang of wheelbarrows under the trommel, plan for this in advance by ensuring youll have the clearance needed for a wheelbarrow to roll under the trommel. I added corrugated metal as a chute to send compost fines down into the tubs and reduce the mess. This is an area I would change as I mention below under Improvements.

Finally, the drive mechanism. The trommel needs to rotate. There are several ways to add power transmission to the screen. You can use the support wheels to drive the drum, you can use a belt drive or chain drive, or you can put a gear on the outside diameter of the screen.

Another key component to the trommel is final RPM. How fast should it spin? I looked at trommels spinning on YouTube and counted their RPM. Somewhere between 10 and 20 RPM seems like the best fit. Mine is a little on the slower side at 12ish RPM. Im ok with that because I have the occasional worm that I dont want to hurt if it goes through the screen.

To reduce the RPM of my 1725 rpm 1/4hp motor I used belts and pulleys. There are calculators online that will help you figure out your speed reduction. Just hit up Google and ask for pulley calculator. To figure out the length of belts to use, check Google for v-belt calculator. An online calculator will ask you the distance from center point to center point of each pulley. It will also ask for pulley diameters. It will tell you the length belt to use!

The motor is attached to the top of the frame. It has a diameter output shaft. OnMcMaster-CarrI purchased two 1- diameter pulleys, a 10 diameter pulley, a 12 long D-profile steel shaft, and two pillow block bearings for shaft. The pillow block bearings are mounted to aluminum to reduce binding between the bearings.

To drive the compost trommel I originally intended to run the belt between two bike rims. When I tested this out it slipped and couldnt turn the drum. So I put the belt in the groove of the rim and it worked like a charm.

I bought some replacement electric cord at the hardware store and ran it to a plastic, weatherproof junction box. Inside the box is a typical light switch which can handle the amperage of the motor. I used weatherproof cord grips to keep the elements out of the box. The cord is clamped to the frame, which ensures it wont get wound up in the moving parts.

Hey, I cant complain. I built this trommel for under $500. It works well and it eliminates a bottleneck in the garden. Ive been using a screen on the first section and screen on the second section. The trommel screens about 2 cubic yards of input volume in an hour (depending on how dry the compost is). Finally, I can swap out screen sizes with relative ease.

how to build a motorized trommeland why on earth you would want to

how to build a motorized trommeland why on earth you would want to

Brian's the earth-biscuit type, with a flop of blond hair and a kayak rack on his Jeep that he actually uses. He's a community-garden aficionado and a yard farmer who could talk compost for hoursmostly because there's a massive heap of it in his backyard. Brian's compost pile is the Everest of our neighborhood. It is robust of scent and full of twigs, old pineapple rinds, his Australian shepherd's buried rawhide chews, and gigantic mounds of last year's oak leaves. And buried deep inside is some of the best compost Mother Earth has ever cooked.

A few years ago Brian built a manual compost sifter, just a big screen within a frame, and he shook small batches of compost through it, separating the fine material from whatever hadn't finished breaking down. He used the rich matter to top-dress his lawn, which improves moisture retention and soil structure, and to make his flower and veggie beds go nuts. He reduced the size of his compost mound and made room for the fall leaf drop in our neighborhood.

Then Brian unearthed an old rock bed left behind by a previous owner and thought about how great those rocks would look on the other side of the yardbut first the bed would need to be sifted and cleaned. The very thought of putting it all through his manual sifter nearly put him in traction. So he hit the Internet to find a better solution.

You know how it goes. You start a project, then halfway through Saturday you're surrounded by tools and a half-finished mess. Brian had watched hours of YouTube videos by guys who'd successfully built mechanical trommels before himguys like Paul Miller of La Mesa, California.

He watched as Paul framed a basic cylinder with bike rims and screening, then mounted it on a wooden frame with smaller wheels turning the sieve within the rims. Atop the structure he mounted a motor. The whole thing sat at an angle, so when Paul shoveled rough material into the higher end, the cylinder dropped fine material below and dumped chunky debris into a wheelbarrow or hopper.Brian got to work on the cylinder first:

1. Use three 24- to 26-inch bicycle rims for the cylinder frame. Brian grabbed his from the local bicycle collective. When I interviewed him, Paul said a friend who fixes bikes donated his. You get the idea.

He wasn't sure. Other projects filled his workshop. The trommel took a back seat. Eventually, Brian moved the cylinder into the backyard, where he felt bad about it for two years. The compost pile grew and grew.

Like I said, Brian's green-living credo is pretty infectious. I wanted to help him finish his trommel, so I figured I'd start at the heart of the problem: the motor. Lucky for us, our other neighbor, John, is a mechanical engineer for a major international manufacturer.

"The goal here is not to slow down the motor but to control a properly sized energy source," John says. The rotational speed of the trommel is critical for safety. About 20 or 25 rpm would be plenty. Plus, lowering the machine's speed would increase its torquethe twisting force that creates rotationallowing Brian to sift larger piles of compost.

A basic -hp electric motor spinning at 500 rpm is obviously too fast to couple directly to a trommel. Additionally, that same motor creates about 5 lb-ft of torque, which is not enough to do the job. To make the motor work, John says the easiest solution is to purchase a speed reducer. These affordable, mass-produced units are readily available from industrial distributors and many websites. Essentially a speed reducer is a gearbox.

"In addition to reducing the speed to a manageable level, it'll increase the torque," John says. "The neat thing about gears is that when you arrange them such that the output speed is reduced, the torque increases inversely." For example, if you connect a 500-rpm motor to a speed reducer, and the output speed is now 25 rpm, or 0 of the original speed, your torque now increases by a factor of 20.

"Industrial supply houses and motor distributors can help you put a nice little package together," he says. "Ask an electrician to make sure your circuit is wired correctly to withstand the load from the motor."

Instead of using a speed reducer, Paul, the YouTube guy, rigged up a machine using the trommel's center rim for speed control. "I used a 21-inch bike rim as a pulley wheel to step down the rpms of the motor," he says. Other trommel builders use a 1,750-rpm motor with a 2-inch pulley (A) going to a 10-inch pulley (B), then a 2-inch pulley (C) going to the 25-inch trommel frame (D).

1. The size of the frame will depend on the size of your cylinder and the position of the wheels you use to turn the cylinder within it. Brian planned to mount his trommel on caster wheels from the local Habitat for Humanity ReStore, but you could also use small wheels with an axle from a home store.

2. Frames are best made from 2 x 4 material with a plywood top that's sturdy enough to attach the motor to. (One YouTube builder made his motor mount adjustable for height because his pulley belts stretched out over time and he wanted to be able to tighten them.)

3. Screw the wheels directly to the frame to turn the cylinder. Paul Miller recommends just screwing the caster into the middle of a 2 x 4 and lining up the caster wheel with the middle of the bike rim, repeating on all four sides at each end. "There was no planning or measuring involved," says Miller. "I just basically built a square around the rims."

5. Here's where you can customize. Some of the YouTube builders added a piece of sheet metal as a guard on one side of the trommel so it doesn't fling dirt and debris all over the yard. Some builders crafted different drums for different purposessmaller screens for composting, larger screening for rock jobs. Others made the trommel contraption high enough that it could be directly positioned over raised garden beds to reduce the amount of shoveling required.

application and working principle of shaftless trommel screen | lzzg

application and working principle of shaftless trommel screen | lzzg

The shaftless trommel screen drum unit is mounted on the frame at an angle and is designed without a central shaft structure. The motor drives the pinion gear to rotate with the large gear of the drum or the chain and the gear on the drum. The motor drives the chain drive or the roller is placed on the two rollers, and the motor drives the roller to drive. The roller device rotates under the driving of the driving device. After the material enters the roller device, due to the tilting and rotation of the roller device, the material on the screen surface is turned over and rolled, so that the qualified material (the product under the sieve) passes through the bottom of the rear end of the roller. The material is discharged, and the unqualified material (the product on the screen) is discharged through the discharge port at the tail of the drum. Due to the turning and rolling of the material in the drum, the material stuck in the screen hole can be ejected to prevent the screen hole from being clogged. Application of trommel screen The shaftless drum screen is mainly used for grading treatment of strip-shaped and entangled materials and is widely used in electric power, mining, metallurgy, building materials, chemical and other production industries. It is often used for the classification of refractory materials, coal, fertilizer, sand field stones, as well as the screening of sticky materials such as coal, coke, white ash, gold deposits, etc., to make the product structure more even to meet the production needs. Advantages Compared with the drum screen with the central shaft, the shaftless drum screen has a simpler structure. At the end of the drum screen close to the vibration motor, several steel bars are evenly welded around the drum, and the other end of the steel bar is gathered to the drum. On the central axis, after the fixing, the vibration motor is connected through the gear. When the vibration motor is started, the drum is also rotated, and the same screening principle as the roller screen of the shaft is used. The shaftless drum screen is relatively more material-saving, and the space for screening the material is larger. It is also easier to repair when the drum fails, so the use of the shaftless screen is also very much. For example, it can be used for pre-treatment of domestic garbage. It can filter out the required garbage. The advantage of no shaft is that it can avoid the entanglement of materials and the screening efficiency is relatively high.

The shaftless trommel screen drum unit is mounted on the frame at an angle and is designed without a central shaft structure. The motor drives the pinion gear to rotate with the large gear of the drum or the chain and the gear on the drum. The motor drives the chain drive or the roller is placed on the two rollers, and the motor drives the roller to drive. The roller device rotates under the driving of the driving device. After the material enters the roller device, due to the tilting and rotation of the roller device, the material on the screen surface is turned over and rolled, so that the qualified material (the product under the sieve) passes through the bottom of the rear end of the roller. The material is discharged, and the unqualified material (the product on the screen) is discharged through the discharge port at the tail of the drum. Due to the turning and rolling of the material in the drum, the material stuck in the screen hole can be ejected to prevent the screen hole from being clogged.

The shaftless drum screen is mainly used for grading treatment of strip-shaped and entangled materials and is widely used in electric power, mining, metallurgy, building materials, chemical and other production industries. It is often used for the classification of refractory materials, coal, fertilizer, sand field stones, as well as the screening of sticky materials such as coal, coke, white ash, gold deposits, etc., to make the product structure more even to meet the production needs.

Compared with the drum screen with the central shaft, the shaftless drum screen has a simpler structure. At the end of the drum screen close to the vibration motor, several steel bars are evenly welded around the drum, and the other end of the steel bar is gathered to the drum. On the central axis, after the fixing, the vibration motor is connected through the gear. When the vibration motor is started, the drum is also rotated, and the same screening principle as the roller screen of the shaft is used. The shaftless drum screen is relatively more material-saving, and the space for screening the material is larger. It is also easier to repair when the drum fails, so the use of the shaftless screen is also very much. For example, it can be used for pre-treatment of domestic garbage. It can filter out the required garbage. The advantage of no shaft is that it can avoid the entanglement of materials and the screening efficiency is relatively high.

The shaftless trommel screen is mainly used for grading treatment of belt-shaped and entangled materials. It is used for the classification of refractory materials, coal, fertilizer, sand field stones, and the selection of coal, coke, white ash, placer gold, and other viscous materials to make the product structure more uniform to meet the production needs. Shaftless trommel screens are relatively

At present, the screening tools are mainly divided into fixed screen, rotary screen, vibrating screen and swing screen. Which screener is suit for domestic waste separation? Domestic waste refers to solid waste generated in daily life or activities that provide services for urban daily life, as well as solid waste that is regarded as urban domestic waste by laws and

The gold washing trommel screen is very efficient in quickly screening large quantities of materials. In areas with high clay content, this sieve is also an essential gold mining tool. Gold, silver, lead zinc, tantalum-niobium, tin, and other rare and precious metal ores. Trommel screen structure The shaftless drum screen machine is mainly composed of motor, reducer, roller device, frame,

The shaftless trommel screen is suitable for sieving stone, sand, the garbage of various properties, and damp and easily clogged materials. The product under the sieve is 200mm, the middle is 20-40mm, and the thickness can be less than 5mm, with a self-cleaning device. The transmission mode is divided into three types: large and small gear transmission, sprocket chain transmission,

what is trommel screen and how does trommel screen work | m&c

what is trommel screen and how does trommel screen work | m&c

Trommel screen, or rotary screen, is a kind of mechanical screening machine which is widely used in the separation operation. It controls the material separation by the particle size, and the separation precision is high. The cylinder of the trommel screen is generally divided into several sections, depending on the specific situation. The mesh holes are arranged from small to large, and the mesh hole diameter on each section is the same.

When the material enters the drum screen, due to the inclination and rotation of the roller device, the material on the screen surface will turn over and roll, so that the qualified material will be discharged through the outlet at the bottom of the drum, and the unqualified material will be discharged through the outlet at the end of drum.

1. It is used for sand screening in sand plant; 2. Used as sand screening machine to screen sand and stone; 3. Used as gold washing equipment for screening and cleaning sand, stone and gold; 4. Used for screening mineral materials in gold boat.

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