I drew the sketch sans spring...December 15 2011 at 5:59 PM
|Ron (Login oo7fuzz)|
Crosman Forum Member
from IP address 18.104.22.168
Response to Let's consider your sketch
....so we should be able to discount the cracking force to compress the spring. Since we do not use a spring, a cracking force still must be achieved. But I think that account rests more with the seal material we choose.
We can apply more pressure to the pump side of the poppet than exists in the reservoir without totally breaking the seal. We only need to apply enough over pressure to drive the poppet back far enough to start decompressing the the Delrin, o-ring or whatever we have chosen for the seal material. This will expose a non seal area for air to pass.
I don't think much pressure differential is involved.