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Bash valve concept musings

Posted by Bill Hinote 
Bash valve concept musings
November 23, 2013 11:08PM
Hi all:

While working on my ongoing steam kart project I have also been watching Tom Kimmel's wonderful website, chronicling his accumulation of steam power hardware and documentation.

One of the more interesting (to me) was this post: [kimmelsteam.com]

--the reason is, this may be a route to an excellent version of a highly serviceable bash valve IMO. The use of a spring-steel reed valve from a compressor app has a lot of attraction--it's ultimately low in inertia (to allow maximum revs) and has great flow relative to its surface area. Also, the physical construction of a valve assembly using a reed valve is about as simple as it gets. The reed valve is highly conformal and requires no lubrication, and the retainer screws for the reed imply alignment under any conditions.

Does anybody (Tom??) know of any significant apps for this type of bash-valve intake?

I'll continue on my own path using silicon nitride balls for the bash valves--but I think the reed valve concept may hold some hope for maximum performance for a bash valve.

All comments welcome here.

Bill
Re: Bash valve concept musings
November 24, 2013 09:53AM
The only real issues I see with converted reed valves are:

1. Superheat. You can only run spring steel so hot until it ceases to be a spring. This will tend to limit you to relatively cooler steam conditions.

2. Lift. I'm not sure how high the reeds lift, most reed valves with which I'm familiar don't have great lift. This isn't that huge an issue if you want a very short cutoff but, combined with the cooler steam temperatures implied above it might result in the expansion curve intercepting the saturation curve with attendant loss of efficiency.

Of the two potential issues, the first is inherent, high temperature will zap the springs. Lift is more a function of a particular valve, in general, larger reed valves also have higher lift. Since the concept involves fitting a new head to a compressor, the cylinder head only needs a single valve versus the two that were originally fitted. A larger reed valve could be installed into the new head if greater lift was desired.

Regards,

Ken



Edited 1 time(s). Last edit at 11/24/2013 11:19AM by frustrated.
Re: Bash valve concept musings
November 24, 2013 09:42PM
I see two potential problems. The valve swings to some extent. It is not a straight line movement. So the lifting pin will either have to flex or slid. So some ware factor. And either way it puts a side load on the pin.
TH
Re: Bash valve concept musings
November 26, 2013 06:27PM
Just how hot are you planning to run your steam? Depending on your material selection you should be able to get over 500C for a very long time. 600C, that may start to be a problem. Also depends on how you got your strength, by quench and temper versus cold work or alloying.

Tom
Re: Bash valve concept musings
November 26, 2013 07:12PM
steamerandy Wrote:
-------------------------------------------------------
> I see two potential problems. The valve swings to
> some extent. It is not a straight line movement.
> So the lifting pin will either have to flex or
> slid. So some ware factor. And either way it puts
> a side load on the pin.

Andy:

With a typical lift value for a bash valve at .035" and a typical distance between the anchor points and the lift pin of about an inch, the deflection angle is almost too low to measure.
Re: Bash valve concept musings
November 26, 2013 07:17PM
TH Wrote:
-------------------------------------------------------
> Just how hot are you planning to run your steam?
> Depending on your material selection you should be
> able to get over 500C for a very long time. 600C,
> that may start to be a problem. Also depends on
> how you got your strength, by quench and temper
> versus cold work or alloying.

Tom:

Thanks for your input.

My current venue operates at the low end of the temp and pressure ranges for steam power, and I was relating my comments to those parameters. That would be pressures below 200 psig and temps below about 500 degrees F.

I appreciate the limits that are placed on a spring steel reed valve, I'm just trying to help somebody (maybe even myself!) find simple but effective methods to build a steam power system--even if it means limiting the operating parameters to protect the materials and mechanisms.

Bill
TH
Re: Bash valve concept musings
November 26, 2013 07:46PM
Bill,
You could probably use steel shim stock for that. It should last roughly forever at that temp and small deflection. It's been a while since I used it, but tool and die suppliers should have it in all sorts of sizes and thicknesses.

Tom



Edited 1 time(s). Last edit at 12/02/2013 07:15AM by TH.
Re: Bash valve concept musings
November 26, 2013 07:58PM
TH Wrote:
-------------------------------------------------------
> Bill,
> You could probably use steel shim stock for that.
> It should last roughly forever at that termp and
> small defection. It's been a while since I used
> it, but tool and die suppliers should have it in
> all sorts of sizes and thicknesses.

Hi Tom:

Thanks again for your input.

I'm going to stick with my silicon nitride balls for bash valves for the first iteration on my kart project. I'm considering that I could substitute spring steel reed valves with relatively little effort, if necessary. My goal is to achieve a high-flow, high-rpm engine and I'm intrigued by the possibility of reed valves fulfilling the job at the intakes.

Good 'ol McMaster-Carr has lots of product available, look at this link: [www.mcmaster.com]

Bill
Re: Bash valve concept musings
January 10, 2014 11:15PM
The Aussies ran a bash valve system on solar power for several years; you can read on that
here:

[www.rossen.ch]

- Bart

----
Bart Smaalders [smaalders.net]
Re: Bash valve concept musings
January 12, 2014 08:39PM
Attached find a pdf file containing a student thesis on the expanders used in the White Cliffs Project. The units were built around small Lister Diesels (with some Jimmy parts); a brutishly primitive engine that is almost unbreakable and thus nearly ideal for the job. The Lister readily facilitated uniflow construction because it uses bolt on cylinders, allowing new uniflow cylinders to be fabricated and attached along with the bash valve cylinder head.

The auto industry tends to limit peak valve acceleration to about 450 gees for push rod engines and about 750 for overhead cam, faster moving valves can be built but they tend to wear out quicker. Actually, given that modern gen sets typically have 20,000 to 40,000 hour TBOs, I would expect to use somewhat lower values in a fixed generator installation. A moments reflection will show that valve acceleration is essentially infinite when the lift pin hits the valve (well, the materials give a bit so it isn't quite so impossible as theory would imply) and likewise the same holds true when seating...so we have grounds to suspect that perhaps the bash valve may be problematic in long term use.

Mr. Shepherd's thesis examines both the theoretical and actual condition of the engines after they were decommissioned. As would be expected, the valves were problematic to the point that he examines the possibility of using solenoid valves at the end of the paper. Personally, I think a good cam and poppet valve mechanism should be more than sufficient if careful attention is applied to valve acceleration and managing differential pressure across the valve. Anyhow, the paper is linked up above for your perusal.

Tom Kimmel sent me an e-mail about a month ago telling me of a variable cutoff bash valve engine that he found in Wikipedia. After contacting the developer he received an 8 MB animation showing operation of the bash valve, it being lifted more or less in the typical fashion but held open with an electromagnet. The file is a bit large but Tim Nye recognized the concept and clued us in that there is an accompanying You Tube video:

[www.youtube.com]

Being the eternal spoil sport, I had to note that Ralph O Hood developed almost the same idea for the "Simplex Electronomic Steam Buggy" back around 1900. I attached the relevant patent above (US # 694,547) for your edification and to make the point that you really should do some research before investing money in steam patents.

Regards,

Ken



Edited 1 time(s). Last edit at 01/12/2014 09:03PM by frustrated.
Attachments:
open | download - Shepherd_James_ENGN4200_2010.pdf (2.65 MB)
open | download - US694547.pdf (358.8 KB)
Re: Bash valve concept musings
January 12, 2014 10:59PM
frustrated Wrote:

> The auto industry tends to limit peak valve
> acceleration to about 450 gees for push rod
> engines and about 750 for overhead cam, faster
> moving valves can be built but they tend to wear
> out quicker. Actually, given that modern gen sets
> typically have 20,000 to 40,000 hour TBOs, I would
> expect to use somewhat lower values in a fixed
> generator installation. A moments reflection will
> show that valve acceleration is essentially
> infinite when the lift pin hits the valve (well,
> the materials give a bit so it isn't quite so
> impossible as theory would imply) and likewise the
> same holds true when seating...so we have grounds
> to suspect that perhaps the bash valve may be
> problematic in long term use.

Ken:

Thanks so much for posting relevant info, there's not much out there!

I had several thoughts (which others might find obvious):

First, the use of extremely hard materials for the bash valves such as silicon nitrides also implies potential increases in accelerative values since the material has so little dimensional "give". It would be interesting to calculate the instantaneous G value for this material in our app here. The point of initial contact must create astounding accelerations!!

Then, it occurs to me that the bash valve itself is experiencing a relatively tame environment (after initial acceleration) due to the rapidly decaying rate of lift which remains in the sinusoidal cycle as it is exposed to the conversion of rotation at the crank into motion at the piston.

Combining these two effects it would seem that the initial acceleration is the most important of the two effects; if the valve can survive this event the rest is just a "walk in the park".

One also wonders if the use of a silicon nitride material doesn't create excessive "bounce" or return of energy into the system--which could result in undesirable resonances. My recent experience with a Si3N4 ball bouncing away out of reach has magnified my sensitivity to this BTW.

FWIW

Bill
Re: Bash valve concept musings
January 12, 2014 11:56PM
Bill Hinote Wrote:

It
> would be interesting to calculate the
> instantaneous G value for this material in our app
> here. The point of initial contact must create
> astounding accelerations!!

I found this interesting statement in the PhD paper--a generalization for sure but a confirmation of the above:

Whilst it is a little presumptuous to assume that the
check used here is valid, this approach seems to add credibility to the result that the stresses
resulting from the point contact are probably in the order of Giga Pascals.


Whooeeee!!

B.
Re: Bash valve concept musings
January 13, 2014 09:06AM
I would that rather accelerating there would be considerable deformation of the lift pin and or valve. Sense you are using a very hard silicon nitrides ball and it didn't break the lift pin deformed. I don't know if you have the resources but it seams the obvious would be to provide some cushion on the initial contact. This idea occurred to me as a way to shift the valve opening closer to TDC and extend it open duration after TDC. But would also cushion the lift. Would require a bit of mod to the piston though. Any have a spring loaded lift pin. It would make contact before TDC and be designed to reach lift force close to TDC. The pin would compress the spring to the that point. The valve would be lifted by the spring force. Jay Carter told me he tried something like this. The problem is finding a spring that can take the steam temperature.
Re: Bash valve concept musings
January 23, 2014 03:52PM
Hi all:

Please see the attached image.

It's a test sample of a possible reed valve for use in my Predator 212 engine from Harbor Freight which I intend to power my steam kart project with.

I'm having considerable problems with the bash valve assemblies I conjured up using silicon nitride balls and high-quality plumbing parts for the seat and chamber. In particular, the ball seems to be "floating" instead of seating solidly as it should.

There are several possible reasons for this:

1. The ball is unguided when off its seat.
2. There is no spring to force the ball back to the seat.
3. The entry port for the steam is on the side of the "valve body" and may be creating an off-center force due to its entry velocity.

A crude test (blowing through the entry port) shows that the ball easily seats and seals in a static mode--but it appears that dynamic forces are quite different and it may take some time to ID the problem and create a fix. In light of the fact that I'm trying to maintain a "KISS" concept I've decided to take a different approach.

Keeping in mind that my proposed operating parameters for the steam are 150 psig and 100 deg. F superheat (which is then about 465 deg. F) the use of stainless steel reed valves may solve my current issues. Here are some advantages I can see regarding their use:

1. The valve is guided (or maybe restrained from wandering) by its method of mounting.
2. The valve automatically incorporates a return-to-seat tension by its very nature.
3. The valve has very low mass-to-volume ratio, possibly the best of any and matching or exceeding the disc valve IMO.
4. The effective seating area is massive relative to the port size and the thin nature of the valve implies a degree of conformality (is that a word?) which ensures sealing at the port even with a less than optimum fabrication.
5. Cost of fabrication is ultimately low. I have enough stock in hand to make several hundred valves (!).
6. Ease of manufacture, I can cut and finish a valve in less than 10 minutes.
7. Ease of replacement, with the right sort of access it should be possible to replace a defective valve in less than 5 minutes.

The attached image shows a possible proof-of-concept prototype. The valve reed is 1.0" x 2.0", .016" thick. Material is 301 SS "half-hard". The port underneath is 1/2-inch diameter, edges slightly relieved. The mounting is by 2x 6-32 SS screws with washers. The base material for this experiment is just a chunk of 1/8 thick 2024 aluminum, I would use a piece of 3/8 thick cold-roll steel for the actual effort.

The reed seals quite effectively to the port even without the backpressure which would ultimately "seal the deal". The proposed lift value of .035"-.040" doesn't begin to approach the yield for the material.

I'll note that the reed valves removed from my HF compressor conversion project measured only about .010" thick and the compressor is designed for pressures up to 150 psi so my prototype would seem to be quite rugged by comparison.

The question of durability has to be considered; the potential wear areas are on the valve where it seats onto the head plate and the local forces applied by the lift pin on the piston. Of these the lift pin is by far the biggest potential source of wear due to load concentration. Another factor is potential failure due to repetitive bending stresses on the reed valve as it flexes open and closed; the motorcycle industry has long since utilized curved backing plates which de-concentrate the bending forces and spread them out to improve performance at very high HZ and to improve reliability by orders of magnitude. This would be an easy upgrade to implement if necessary--but my contention is, for the garage-level steam enthusiast a valve lifespan of 20 hours would seem to be more than adequate given the expected operating times, the ease of fabrication, low cost and ease of replacement.

IMO the move to reed valves for the intakes is a no-brainer, I'll be implementing this soon and will report results on my blog about the kart project.

Thanks for listening and all comments appreciated as usual.

Bill



Edited 2 time(s). Last edit at 01/23/2014 03:59PM by Bill Hinote.


Re: Bash valve concept musings
January 23, 2014 04:29PM
Thought that I would mention an experience that I had using ball bearings in check valves. After many miles the check balls get a groove worn in where they contact with their seats. As luck would have it, the balls finally rolled a little in their seats and now they no longer seated because the ball's worn ring no longer matches up with their valve seats. That is why the Stanley Steam Car company put stems on their water pump's check balls. With a guide stem, the check ball always returned to the same worn seat pattern after every cycle.
Re: Bash valve concept musings
January 23, 2014 05:35PM
SSsssteamer Wrote:
-------------------------------------------------------
> Thought that I would mention an experience that I
> had using ball bearings in check valves. After
> many miles the check balls get a groove worn in
> where they contact with their seats. As luck
> would have it, the balls finally rolled a little
> in their seats and now they no longer seated
> because the ball's worn ring no longer matches up
> with their valve seats. That is why the Stanley
> Steam Car company put stems on their water pump's
> check balls. With a guide stem, the check ball
> always returned to the same worn seat pattern
> after every cycle.

Thanks for your input.

I hope others will share their experiences with ball-to-seat valving.

In my case, the use of silicon nitride balls would preclude any sort of wear even under the severest possible conditions. I would suggest the substitution of these in any app where "lesser" materials are in use and may be experiencing early failure modes.

B.
Re: Bash valve concept musings
January 24, 2014 01:31PM
Thanks for the links Ken.

Unfortunately there is not a lot that is truly definitive in Shepards paper. For example;

"Ironically, as will be seen in Section 3.4 the maximum height that the pins can be installed into the engine without causing interference between the valve ball-bearings and the valve guide plate are almost exactly the same as the deformed height of the extracted bash pins."
pg 20 (pg 33 in pdf)


"The most interesting development taken from the determination of the pin height’s, was that the pins that had been removed from the assembled were almost exactly the same height as the calculated value. This leaves open the possibility that at some stage these pins were installed with their length’s too long. Had this occurred it would be remarkable if the only damage that resulted was the compression of the pins to a point where the excess height was deformed out in a similar fashion to that seen in Figure 2-9. However, if this scenario was the case then there is the chance that the material used to construct the pins is appropriate and can with stand the stresses; in which case this investigation may all have been in vain and someone has a lot of explaining to do."
pg 35 (pg 38 pdf)


So, are the lift pins deformed because of normal wear or did they interfere when they were initially installed?
If the number of operational hours is unknown, how useful is his analysis?
It seems the development of the White Cliffs engine was never completed.
The use of ball valves should have been the first thing to go and it sure seems like the exhaust system is undersized... but, if it worked well enough at 1500 rpm, why bother?

I suspect the Carter system is the best benchmark for what is possible in bash valves. The few experiments I've done seem to confirm their observation that materials are not the limiting factor for these valves.
Chuckw
01/27/2014--implementing the plan
January 27, 2014 10:41PM
Hi again:

The attached image is a scan of a working drawing I made up, to implement a change to reed valves for the "bash-valve" intake scheme. The 2 centered holes in vertical alignment are 7/16-inch diameter ports in the head plate which match the existing lift pin locations. The reed valves are inclined 30 degrees off vertical, to provide the necessary "acreage" to accomodate them. The crude drawing (not to scale) on the left delineates the dimensions for the reeds.

The head assembly will now consist of 4 pieces of plate stock. Starting with the piece which is nearest to the piston and working upward as follows:

1. The clearance plate. This establishes the clearance volume in the cylinder at top dead center. Already made and tried, it's 1/8-inch thick. Keep in mind that the piston has an essentially flat top; the original clearance volume was cast into the underside of the cylinder head, it's important to relate the final volume to the operating pressure so as not to create excessive recompression on the upstroke which will narrow the indicator card and reduce power excessively. This is a nice piece to have, the thickness can be varied with experience to create the "best" compromise in final compression.
2. The head plate. This part actually seals and creates the top of the cylinder. In my case the upper surface is also what the reed valves will seal against. Materials on order, it's made from 3/8-inch CRS.
3. The spacer plate. This is a piece of 1/4-inch thick aluminum which is clamped between the head plate below and the "clamp plate" above (see #4 below). Its interior is cut completely away and a chamber is the result which the reed valves operate in. The chamber volume will be augmented by an auxiliary clearance volume device as before.
4. The clamp plate. This is another piece of 3/8-inch CRS which creates the "ceiling" of the chamber the reed valves will operate in. Actually I'm converting the existing head plate to use as this part. The 3/8 NPT holes will now house converted plugs which are threaded for the valve stop bolts.

Additional details:

1. The steam supply is now direct to the chamber created by the spacer plate, through the 3/8-inch steam line threaded into the (top) clamp plate. No splitting of the line into smaller feeds to each valve with excessive fittings. I suspect a considerable increase in potential flow with this change.
2. The port diameter under the reed valves is 7/16 nominal, .4375"; this compares favorably with the previous port diameter for the ball valves which used 3/8 NPT fittings and the approximate ID was then about .375". The reed valve doesn't present a consistent opening around its entire circumference due to being anchored at one end; I believe the increase in port area will offset this. The intake port which the reed valve covers is actually much refined over the previous effort, its underside will be relieved to create an aerodynamically superior shape which will avoid the dreaded "vena contracta". Again, a reduction in hardware and the crude transitions they create.
3. I'm hoping the 3/8-inch CRS material will provide the necessary stability and rigidity for this app in the head plate and the clamp plate; if necessary I may add additional bolts along the 2 "longer" sides to provide additional clamping strength. BTW I upgraded the 4, 8x1.25 metric head bolts considerably by substituting grade 10.5 spec, with washer heads. Essentially the best you can buy without going into aerospace hardware.

Stay tuned, I'll provide more photos as things progress.

Bill



Edited 4 time(s). Last edit at 01/28/2014 12:00AM by Bill Hinote.


Re: 01/27/2014--implementing the plan
January 27, 2014 11:12PM
Hi ChuckW,

They did get a couple years out of White Sands, and the documented bash valve maintenance interval was 1000 hrs, not too bad considering. I thought they could have gotten a lot more out of it, but someone came along and installed PV instead, and that was then decommissioned. (best of my recollection at the moment.) Anyway, Cheers, Keith
Re: 01/27/2014--implementing the plan
January 27, 2014 11:25PM
Bill

It might be interesting to see how much the valves leak. Perhaps air or steam could be admitted to the inlet connection with the piston at bottom dead center.

Kerry
Re: 01/27/2014--implementing the plan
January 27, 2014 11:49PM
kerry Wrote:
-------------------------------------------------------
> It might be interesting to see how much the valves
> leak. Perhaps air or steam could be admitted to
> the inlet connection with the piston at bottom
> dead center.

Kerry:

Thanks for your comment.

So far, the sealing effect seems quite good, I did a crude check with the proof of concept. In particular the conformal nature of the reed valve would appear to provide a lot of assistance in this regard (what that means is, the material seats on the area immediately surrounding the port--but actually deflects slightly, directly over the port due to differential pressure This creates an improved seal compared to hard materials interfacing with each other). Also, the relatively large area which the differential pressure acts upon creates excellent sealing forces which are augmented by the natural springiness of the valve.

In any case, the valve is gonna seal the port!! This will be a massive improvement over the (failed) ball-type I had originally installed and which were simply not seating for some reason. It would seem possible to research the cause of this failure and to fix it--but the press of time has dictated a simpler solution.

Part of the developmental issues that we encounter in projects like this is to make decisions about how to keep the project moving forward in spite of problems which pop up. I've encountered any number of folks who would say to me, "why didn't you do it this way?". My answer is always that I considered all the variables I could and made a decision to move forward. If that wasn't the best decision I can only say that having decided I moved ahead. If I have a running project then I can modify the decision later for a better solution--or maybe defend my decision, as is.

That's the nice version, I have a nastier one for some other folks out there (not you BTW). Thanks for participating and for your continuing interest in my project.

Bill



Edited 1 time(s). Last edit at 01/28/2014 12:11AM by Bill Hinote.
Re: Bash valve concept musings
February 07, 2014 12:13PM
Just wondering about the activation of the reed valves which normally is activated by pressure differentials. The ball valves is mechanical but I'd expect such activation against the steam chest pressure with reeds would quickly wear them out. You may have addressed this but I don't grok the activation principle above.
Re: Bash valve concept musings
February 07, 2014 12:40PM
mekennedy1313 Wrote:
-------------------------------------------------------
> Just wondering about the activation of the reed
> valves which normally is activated by pressure
> differentials. The ball valves is mechanical but
> I'd expect such activation against the steam chest
> pressure with reeds would quickly wear them out.
> You may have addressed this but I don't grok the
> activation principle above.

I'm using lift pins made from 1/4-inch hardened cap screws; they're mounted to the piston with high-quality nuts on each face of the piston crown (i.e., on top and bottom, creating a clamping effect). A stop bolt is placed above the valve to limit how far the valve can flex open due to inertial effects at higher speeds.

Opening forces on the valve are reduced to minimum with the judicious selection of clearance volume which creates recompression values largely negating the steam chest pressure. At lower pressures created by throttling, the valve is actually forced open by the recompression and results in backflow through the intake.

If you go to Tom Kimmel's fine website and look at the Stan Jakuba air compressor conversion to steam engine, this project was run for 500 hours on reed valves.

Bill
Re: Bash valve concept musings
February 07, 2014 01:08PM
Thanks for the answer Bill. So lift pins are still used. Lets see if I decipher the rest well. Piston recompression of trapped steam basically counteracts steam chest pressure. The stop bolt limits the flex of the reed valve so the reed doesn't experience excess bending stress leading to fatigue failure. When you speak of clearance volume is that lift pin clearance or piston head clearance? Would there be a diagram somewhere showing the pins shape/size vs the vent hole as Kimmels site just shows the exterior of the engine?

Max
Re: Bash valve concept musings
February 07, 2014 01:16PM
mekennedy1313 Wrote:
-------------------------------------------------------
> Thanks for the answer Bill. So lift pins are
> still used. Lets see if I decipher the rest well.
> Piston recompression of trapped steam basically
> counteracts steam chest pressure. The stop bolt
> limits the flex of the reed valve so the reed
> doesn't experience excess bending stress leading
> to fatigue failure. When you speak of clearance
> volume is that lift pin clearance or piston head
> clearance? Would there be a diagram somewhere
> showing the pins shape/size vs the vent hole as
> Kimmels site just shows the exterior of the
> engine?

Clearance volume is the space between the piston crown and the cylinder head-end at top dead center.

I'm using a 7/16" port diameter, plenty of flow around the lift pin and with 2 port/valve setups I expect that wire drawing will be minimal.

There's a good photo of the piston showing the lift pins installed in the engine thread.

B.
Re: Bash valve concept musings
February 07, 2014 01:36PM
update 02/07/2013:

Work is progressing on the new head and valve assembly. I expect a first run in about 10 days, weather permitting.

One important change to note is that the valve mounting method shown in the "test sample" photo above has been deemed unsatisfactory as it will concentrate bending stresses over a too small area. Instead, I'm using clamping plates which cover the entire width of the reed valve and which have radiused leading edges for the valve to flex against.

Pending extended testing, I'm hoping this solution will promote the desired reliability in the reed valves. If necessary I will resort to reed valve backing plates as used in modern high-performance 2 cycle engines.

Bill
another update 02/10/2014
February 10, 2014 10:03PM
Hi all:

Been contemplating my update on the intake sysem which will incorporate reed valves instead of ball-type valves.

My initial (brash!) statement about how easy it could be to create the necessary valve reeds has been attenuated by actual experience. I'm finding that the real finesse necessary to create the actual product to the refined status required (and to my standards) may be beyond my capabilities. Also (and as usual!) there are products out there which fulfill my need and which exceed anything I might imagine myself capable of duplicating.

My feeble efforts have revealed defects created by the cutting process as well as the finishing processes from grinding, sanding, etc.

Being somewhat discouraged I reverted to the usual internet search and found these:

[www.ebay.com]

--amazingly, these fit my dimensional specs to within a few thou!! The price isn't totally out of hand and with the part number in hand it's a no-brainer to order replacements as necessary.

I have ordered these and anticipate "easing my pain" and getting a more consistent result instead if they are appropriate for the app.

FWIW

BH



Edited 1 time(s). Last edit at 02/10/2014 10:10PM by Bill Hinote.
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Shepherd_James_ENGN4200_2010.pdf 2.65 MB open | download frustrated 01/12/2014 Read message
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reed valve test sample.JPG 190.7 KB open | download Bill Hinote 01/23/2014 Read message
reed valve drawing.jpeg 129.5 KB open | download Bill Hinote 01/27/2014 Read message