workings of a solenoid valve?

[admin]

Hello all. I’ve been working with automated machinery for a long time, but haven’t learned everything yet and need help with the workings of a solenoid valve? 😉 I’m currently mentoring a high-school robotics team, and our robot uses a single-acting cylinder operated by a solenoid valve. The cylinder needs to run at 20-25psi for proper thrust, and it works fine at that. But, the valve doesn’t work at such low pressure. It hit me that the valve might be a piloted type. I want opinions on whether I understand how it works, or set me straight. I am thinking a piloted valve is a smaller valve operating a larger valve. That the solenoid drives the pilot valve, which ports air to move the larger valve. This would explain why we hear the solenoid click when energized, but no air output when used at low pressure. Do I understand this correctly?

Secondly, are piloted types more common than non-pilot? What are the advantages of the pilot type?

Thanks for all replies!

[admin]

Your problem is probably that your valve is internally piloted. Larger valves use air pressure to shift their spool from a smaller built-in direct solenoid valve. You need to contact the manufacturer or vendor to find out how to change your valve from an internally piloted valve to an externally piloted valve. I just recently went through this with Parker valves…their two position valve requires a minimum of 25 psi to shift the spool and their 3 position valved requires a minimum of 35 psi. This is necessary to overcome the seal friction of the o-rings on the spool.

[admin]

You could also use a direct-acting valve, but it requires more voltage to shift. I agree with the 1st reply 100% though.

[Author]

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