Knife gate valves provide critical on-off isolation points in a piping system. What do you do if the valve does not close when you need it to? With a little planning at the time of specification and installation this situation can be avoided. By selecting a slightly larger air cylinder, many closing problems can be avoided. Below are some situations where an over-sized cylinder is a worthy investment:
Application
Heavy Slurry applications- Scaling applications
- Powder applications
- When shearing of tough or durable materials is required
- When differential pressure exceeds 50 psig
- High valve cycling; multiple times per day
Installation
- When your available plant air is below 80 psig
- Instances that involve high pipe stress
- Large variation in process temperature to ambient temperature
Each of the above valve actuating circumstances can require more closing force than manufacturers typically recommend. The additional closing force in turn requires a more robust upper frame than is found on most slurry valves. It is better to plan for these likely challenging conditions at the time of installation by properly selecting the conservatlivey sized actuation method than to deal with a valve that will not close when you need it to. While we specifically address pneumatic air-cylinders in this post, the same guidance applies to hydraulic and electrically actuated valves.
Jasper Engineering can help determine what would be an appropriate sized air-cylinder for your application as well as help troubleshoot your other valve challenges.
Ready to learn more? Contact Jasper Engineering today at (218) 262-342 or (952) 938-6504, or email us at sales@jaspereng.com
