Featured How shear pin sprockets prevent damage to your valve

Material jams can damage vital parts of your rotary valve and lead to costly repairs. Watch the video to see how shear pin sprockets can help you avoid unnecessary downtime and parts replacements.

Transcript

00:05
Rotary valves can jam up causing downtime.

00:09
This is especially true in running sawdust, wood chips, or any pelleted materials.

00:17
First we will look at a standard set up.

00:20
The gear motor is turning a small sprocket which transfers

00:23
its rotation through the chain to the large sprocket.

00:27
The large sprocket drives the rotor.

00:30
A typical speed of the rotor is 20 RPM.

00:34
Here we see a rotor jam occurring.

00:36
The rotor slows down and then stops.

00:39
The large sprocket stops while the motorized small sprocket

00:42
continues to strain.

00:44
This stresses the motor shaft, both sprockets, the chain and

00:48
the rotor shaft.

00:51
The chain breaks.

00:56
Even a slight bend in the shaft makes the rotor unusable.

00:59
Same for the motor.

01:02
Here we have isolated the large sprocket and we'll look at a

01:05
better alternative.

01:07
This simple sprocket will be replaced by a shear pin

01:10
sprocket.

01:13
The shear pin will break before the chain breaks or any shafts

01:17
bend.

01:18
Let's look at the components of the shear pin sprocket.

01:25
In this exploded assembly, Note 3 critical parts: shear pin, hub and sprocket.

01:33
The shear pin is the key to this improved system.

01:37
This tiny waist will shear before any damage is done to the

01:41
chain, motor, sprockets or rotor.

01:45
The shear pin waist, which has a calculated diameter based on

01:48
load conditions, is ready to shear.

01:51
Think of it as a fuse in an electric circuit.

01:54
Let's reassemble the shear pin sprocket and see it in action.

02:01
The simple sprocket is now replaced by the shear pin

02:04
sprocket assembly.

2:07
If the shear pin breaks, the large sprocket continues to spin

02:10
but it's hub will stop.

02:12
This protects the chains, sprockets and more importantly

02:15
the motor and rotor shafts.

02:18
It's a good idea to have a zero speed switch attached to indicate stoppages.

02:24
Here the shear pin sprocket is in place and ready to run.

02:29
Now we are back running at 20 RPM.

02:33
At the start of any jam there is a very slight strain on the

02:36
chain.

02:37
Note that the shear pin is feeling the strain as well.

02:42
The shear pin is now experiencing its breaking torque.

02:48
The shear pin breaks but the large sprocket continues to spin, freewheeling.

02:55
Only its hub is stopped and this protects the chain and more importantly the motor and rotor shafts.

03:01
A zero speed switch will signal that the valve is down.

03:05
Before proceeding, lockout the power, then free up the jam.

03:10
Push out the shear pin remnants and replace with a new shear pin.

03:14
The alternative that avoids chain breakage and stops permanent

03:18
damage to the sprockets and shafts.

03:23
If you have any questions please contact us.

03:26
Contact information is on our website www.acsvalves.com.