Mechanical valve design

[sb327]

I would like some thoughts from those who have studied and/or designed valves.

We’ve seen a few different style valves come to market. Some hammer fired, some not.

What are the things that make a valve system good vs what you don’t like?

Some things I feel are important
ES
Efficiency
Easy to actuate (cocking/triggering)

Some things that turn me off
Hard cocking
First shot inconsistencies
Odd triggering (like the L2)

What are some of your opinions on what makes a valve good or bad?

Dave

[mackeral5]

In addition to what you have already mentioned, the overall shot cycle is of great importance.  While there are many contributors to shot cycle, the valve is largely responsible for setting the stage so to speak.

[sb327]

I agree completely. Many reasons why the overall shot cycle and the transitions the moving masses make affect the overall performance.

Thanks for that input. Not much traffic in the design department these days. Surely not everyone thinks the best designs are already out there. We see balanced valves in a some factory produced hammer fired guns, but is it the best there is going to be for hammers?

Dave

[mackeral5]

I agree completely. Many reasons why the overall shot cycle and the transitions the moving masses make affect the overall performance.

Thanks for that input. Not much traffic in the design department these days. Surely not everyone thinks the best designs are already out there. We see balanced valves in a some factory produced hammer fired guns, but is it the best there is going to be for hammers?

Dave

Not necessarily the intended topic of your thread, but related....  Your statement above made me consider hammer/spring systems in a way I had not previously thought..... 
I do not know why it took so long to figure this out....but one of my guns that i struggle with 100 yard accuracy with, often times it will do 3 shots in the same hole, as in less than .375 ctc, then shots 4 and 5 take the group out to 1.5".  Most of its 1.5" groups have 3 shots touching.  I just realized that my SSG weighs a ton....the spring guide moves with the spring/hammer.  I bet this is creating a problem with harmonics.....  In the past I used guide fixed at the rear SSG's and never had to consider the shock wave generated by the SSG itself.  I am going to make some immediate adjustments and see how that affects things....

[sb327]

Most definitely a topic of this thread. A valve that requires extra masses moving to be able to operate efficiently will cause other undesirable effects. It’s just another moving part that needs to be kept in harmony.

The balanced valve has been embraced by quite a few but it has some major drawbacks concerning range of tuneability easily (via just hammer spring tension or similar means).

Matt has been working with me on my latest pv design and it is showing some great promise. He has one for his mrod and doing round two of testing. One of its features (not intentional) is that while the hammer may bounce, it can’t refire that quick. And my hammer is only 11.5grams (7.7 now but not tested), so I’m really trying to keep my moving mass low.

What are you going to change on the ssg? It will be interesting to see how it affects accuracy. What about running without it for a bit to confirm it is the issue?

Dave

[mackeral5]

I weighed the moving parts, they are 22-24 grams across the 2 SSG's in question.  That is 22-24 grams accelerating and coming to a hard stop, before the hammer even contacts the valve stem.  All of my previous SSG's were guide fixed at the rear style so all that was moving was the spring and a washer.  Never really considered all of this moving mass until now.. 

I replaced both SSG's with a short stiff spring, yielding similar, possibly even less cocking effort.  So far the shot cycle seems a bit smoother, but need more testing to determine true impact. 

The work y'all are doing on balanced valves has been very informative based on what has been shared publicly.  I look forward to seeing more.

[Rob M]

David , have you looked at the Umarex Hammer valve ? it appears to be a qev valve somewhat similar to your build..I think being easy to open is paramount.  Eliminating the valve stem and moving it to the front of the poppet in a conventional hammer valve is something i explored. Getting that .125 stem out of the throat requires less poppet diam , less throat diam etc

[sb327]

Mike,

That does seem like it would cause an extra event to have to deal with during the shot cycle. Significant anyway.

Rob,

I remember looking at the hammer early on in the piloted valve adventure. I can’t seem to find one to look at now.

I have two different valves that run on the pilot principle. An inline and a conventional. I’ve been working on the conventional one lately. Testing (mine and Matt’s) have shown some surprising results. Efficiency is good, no orings in the design, inability to release air due to hammer bounce, hammer strike tuneable along with the obvious advantages of light hammer strike.

The main disadvantage is that it’s not easy (for me anyway) to build, lol. I could make a couple balanced valves in the time it takes to make this one. But if you like to mess with valves, it’ll be one I suggest to try.

Dave

[Rob M]

yea thats always the challenge, building it , testing , retesting , figuring out what will seal and what wont. I do think the huben style valve is brilliant , but super complex ,, I think the leishy 2 uses something similar.

[mackeral5]

Mike,

That does seem like it would cause an extra event to have to deal with during the shot cycle. Significant anyway.

Rob,

I remember looking at the hammer early on in the piloted valve adventure. I can’t seem to find one to look at now.

I have two different valves that run on the pilot principle. An inline and a conventional. I’ve been working on the conventional one lately. Testing (mine and Matt’s) have shown some surprising results. Efficiency is good, no orings in the design, inability to release air due to hammer bounce, hammer strike tuneable along with the obvious advantages of light hammer strike.

The main disadvantage is that it’s not easy (for me anyway) to build, lol. I could make a couple balanced valves in the time it takes to make this one. But if you like to mess with valves, it’ll be one I suggest to try.

Dave

Dave-  Regarding the current valve you are working on....I could tell there was more to it the way Matt has been rather exclamatory about the fact that the valve is almost accidental discharge-proof.  Whether intentional or not it is almost like he is trying to bait someone in to a debate on the topic.  I look forward to if and when the two of you share what your recent learnings.

Regarding the current Simplified balanced valve....  The ability to tune balance chamber volume via piston height, and the piston being moveable away from the valve seat, that coupled with some type of hammer-induced lift control  and buffer system proved to be very good tuning tools.  I somewhat have  a decent grasp on how they interact, but there is still more to learn.  I paused that testing for a while, degassing to adjust piston height and test was wearing on me.  I'll resume at some point, but for now I returned the test mule back to a simple peek poppet over a minimum for caliber valve throat area....

Mike

[Motorhead]

Not sure where to start .... Designed or been in the R&D loop for so many.

Peek poppets, smaller sealing area, altered throats & transfer paths ....
Cobra valve Tech ....
Balanced valves & Redesigning them for low stiction, no 1st shot drop off, low mass hammers & SSG's etc ....

A more specific Q i could offer input ... general statement creates too much revisiting & typing.

[mackeral5]

Not sure where to start .... Designed or been in the R&D loop for so many.

Peek poppets, smaller sealing area, altered throats & transfer paths ....
Cobra valve Tech ....
Balanced valves & Redesigning them for low stiction, no 1st shot drop off, low mass hammers & SSG's etc ....

A more specific Q i could offer input ... general statement creates too much revisiting & typing.

i am thinking some type of valve that can only be opened by the hammer once, and must be reset by a separate operation, perhaps integrated with cocking.  Perhaps it has a poppet and balance chamber, perhaps it does not. 

Tuneable for dwell/lift, easy to open/close, no susceptible to hammer bounce in any way.

How would we achieve those things?

[sb327]

Not sure where to start .... Designed or been in the R&D loop for so many.

Peek poppets, smaller sealing area, altered throats & transfer paths ....
Cobra valve Tech ....
Balanced valves & Redesigning them for low stiction, no 1st shot drop off, low mass hammers & SSG's etc ....

A more specific Q i could offer input ... general statement creates too much revisiting & typing.

It’s more of just a general question about the what we are trying to achieve with any new valve technology. What goals we are shooting for, so to speak.

Dave

[sb327]

Mike,

That does seem like it would cause an extra event to have to deal with during the shot cycle. Significant anyway.

Rob,

I remember looking at the hammer early on in the piloted valve adventure. I can’t seem to find one to look at now.

I have two different valves that run on the pilot principle. An inline and a conventional. I’ve been working on the conventional one lately. Testing (mine and Matt’s) have shown some surprising results. Efficiency is good, no orings in the design, inability to release air due to hammer bounce, hammer strike tuneable along with the obvious advantages of light hammer strike.

The main disadvantage is that it’s not easy (for me anyway) to build, lol. I could make a couple balanced valves in the time it takes to make this one. But if you like to mess with valves, it’ll be one I suggest to try.

Dave

Dave-  Regarding the current valve you are working on....I could tell there was more to it the way Matt has been rather exclamatory about the fact that the valve is almost accidental discharge-proof.  Whether intentional or not it is almost like he is trying to bait someone in to a debate on the topic.  I look forward to if and when the two of you share what your recent learnings.

Regarding the current Simplified balanced valve....  The ability to tune balance chamber volume via piston height, and the piston being moveable away from the valve seat, that coupled with some type of hammer-induced lift control  and buffer system proved to be very good tuning tools.  I somewhat have  a decent grasp on how they interact, but there is still more to learn.  I paused that testing for a while, degassing to adjust piston height and test was wearing on me.  I'll resume at some point, but for now I returned the test mule back to a simple peek poppet over a minimum for caliber valve throat area....

Mike

I’ll definitely be posting up the latest at some point. Matt has done a good animation of it that shows how it works.

Dave

[MJP]

I personally like the L2 design, but not the actuation mechanism.

I made modifications and different leverage for my own version of the gun.
It's better but could be refined still.

I hate hammer valves, too much harmonics before any movement of the projectile.
And I don't fancy any electronics on a gun.

Small striker or preferably a self setting valve, pressure actuated and trigger just releases the valve for firing. Pressure differential closing to reset.

1 repeatability
2 reliability
3 power

Or if just one shot, all out flow and power.  I could care less about efficiency sound or recoil.
Gun should say bang and give you a positive report that you shot something other than 4.5mm bb gun

All good designs are efficient on what they are meant for.

Air is not a problem, so making the most out of it by reducing power for extra shot in some meaningless string when not tethered is not interesting at all.

Marko

[jackssmirkingrevenge]

I have two different valves that run on the pilot principle. An inline and a conventional. I’ve been working on the conventional one lately.

This is the design that comes to mind:



I'm curious as to what you mean by the distinction between inline and conventional

[Motorhead]

I will say that the Spool valve design and overall operation of the SKOUT EPOCH is pretty dang slick and has nearly all the attributes you seek. ( I own one and played pretty extensively with it )
While the SKOUT uses an electric solenoid to blip the air to open the spool, it could be done mechanically as well with a very small poppet valve such as a BB on a seat struck with a very small & light striker.  LOTS of possibilities with spool valve tech IMO   

[sb327]

For sure that valve interests me. And it may very well be something that is similar in what I’m doing, I’ve just not had a chance to really study the Skouts design.

The Leshiy2 uses a ball check to set things in motion via a direct trigger linkage and the dwell depends solely on jet/pressure.

My newest valve has some similarities but its dwell is dependent on more than vent sizing and has been relatively easy to tune with hammer strike.

Dave

[Motorhead]

Dave,
You have done some nice work previous no doubt.   
Biggest hurtle, or just a reality check is that some of the valve tech simply won't retrofit into an existing platform. Thus the cocking and what ever else doing so also gets set / activated etc stands alone with a new type of firing valve & that = a ground up custom build 

[Motorhead]

The craziest concoction of valve / strike & control was this one that you may recall ?

My inverted poppet Balanced valve ... Adjustable hammer stroke ... Adjustable poppet lift & strike / bounce buffering with an SSG cartridge.
Yea the whole box of tricks in one application.