SharkLover
T5 LPS
Has anyone had any experience with the push/pull gate valves. I currently have one on my skimmer and I think if I switched to a twist type gate valve I might be able to tune my skimmer better. thoughts? comments?
push & pull gate valves versus rotational gate valves
- Thread starter SharkLover
- Start date
nichols
Non-member
Gate valves are the way to go. Much more adjustment to fine tune. This is a gate valve.http://www.usplastic.com/catalog/pr...SPlastic&category_name=16117&product_id=16125
This is a push/pull or knife valve. Not as good as a gate valve.
http://www.usplastic.com/catalog/pr...SPlastic&category_name=16117&product_id=19532
stingythingy45
Well-Known Member
+1
On gate valves.
Nothing beats them for fine tuning the outflow from a protein skimmer.
On gate valves.
Nothing beats them for fine tuning the outflow from a protein skimmer.
Dave Y
Non-member
Just speaking from my "previous life" as a chief engineer in the merchant marine, the push-pull (also called knife valve) is best suited for on on/off apps only. It can cause fluid flow issues when used in mid positions as well as eventual failure at the gate or the shaft seal. Maybe not so bad with low pressure systems...
The ball valve is best for throttling or regulating flow. Fluid dynamics aside, I feel the ball is best overall.
The ball valve is best for throttling or regulating flow. Fluid dynamics aside, I feel the ball is best overall.
Last edited:
ReeferMedic
Non-member
A gate valve is definitely the way to go for fine tuning your skimmer. You will be able to make much more minute adjustments with a gate valve vs a ball valve or knife valve.
OP
OP
SharkLover
T5 LPS
I accidently bought a knife valve which was promoted to me as a gate valve. obviously the seller did not lie however my lack of knowledge ended up with my loss and his gain. I have a "gate" valve coming that isn't a knife hopefully it'll work better.
Dave Y
Non-member
I agree to the minute, fine tune adjustment issue of ball vs. gate.
A ball valve typically goes from zero to full flow in 90 deg of rotation of handle…the smaller the valve the more flow with each bump of the handle. The greater the pressure the more effect per bump, yet there is less resistance to flow...or pressure drop.
One issue to note: gates typically have packing glands and need to be adjusted upon initial and long-term use. If the gland is not tight enough, the fluid can leak through the gland. Good rule of thumb: hand-tighten packing nut, 25% turn with wrench, then back off just a bit…If too tight, can bind the stem and cause deflection.
Again, just one-way to do it.
Needle valves...now there's another animal...
A ball valve typically goes from zero to full flow in 90 deg of rotation of handle…the smaller the valve the more flow with each bump of the handle. The greater the pressure the more effect per bump, yet there is less resistance to flow...or pressure drop.
One issue to note: gates typically have packing glands and need to be adjusted upon initial and long-term use. If the gland is not tight enough, the fluid can leak through the gland. Good rule of thumb: hand-tighten packing nut, 25% turn with wrench, then back off just a bit…If too tight, can bind the stem and cause deflection.
Again, just one-way to do it.
Needle valves...now there's another animal...
