Venting Rotary Valve

Posted in: , on 6. Mar. 2007 - 21:09

I searched through some past messages on this topic but did not find what I was looking for. I have a dilute phase airveyor moving 10tph of dry granular material and I am having trouble feeding material to the valve due to pressurizing the chute above the 14" rotary valve (WM Meyer HD). When I open the purge ports on the side of the valve the material flows fine. I know I need to vent this air but I would rather not send it up 40' to the top of the bin (no d.c. on the bin). The attached photo shows the blower package and the long pipe (8'-10') that is attached to the 70 ton storage bin. What would be some good methods to vent this air and drop the fines back into the rotary valve? I have heard that there are some manufactures that have designed equipment to do this and was hoping for some advice here. Thanks.

Re: Venting Rotary Valve

Posted on 6. Mar. 2007 - 10:17

This is a very common problem with rotary valve air leakage. If this leakage is not vented properly it forms a bubble on top of the valve and material stops flowing down.

If venting to top of silo is not an option, I normally put a tiny hopper on top of the rotary valve with a reverse jet filter. Hopper doesn’t need to be very big just big enough to mount the filter. I assume you can work out the filter area required (not a lot!!!). If the material is not very dusty fan assisted filter is recommended. The cheaper option is breather sock but then it will need regular cleaning.

Dennis Hauch - Freeport, TX, USA
(not verified)

Rv Venting

Posted on 18. Mar. 2007 - 01:03

The Waeschle company offers a vent hopper that addresses your needs. It is a compact design that does not require a filter.

RV vent flow is a function of valve clearance and differential pressure. Reputable RV manufacturers will will publish leakage curves. Try to get one from Meyer, and good luck!

Dennis Hauch, PE

Solving Rotary Valve Feeding Problems

Posted on 20. Mar. 2007 - 03:03

You may like to read my article "Improving Rotary Valve Performance" published in Chemical Engineering in its issue of March 2005. This article gives solutions to feeding problems due to poor venting system design.


Amrit Agarwal

Consulting Engineer

Pneumatic Conveying Consulting


Ph and Fax: 304 346 5125

Re: Venting Rotary Valve

Posted on 23. Mar. 2007 - 10:55

If you are looking for a rotary valve venting system that really works, visit and forget all that nonsens about venting hoppers etc

Vilas Wadekar
(not verified)

Venting Rotary Valve

Posted on 30. Mar. 2007 - 06:00

Indeed Venting Rotary Valve Using vent venturi Is great experience.What mptkal Says Most practically correct way

See Rotary valve section For Such venting