Office of Steam Logo_1

Author Topic: High bypass check valve for piston water pump build.  (Read 112 times)

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
High bypass check valve for piston water pump build.
« on: September 04, 2020, 01:01:17 am »
In the quest to make the M91 do some work, I took a day off from building the woodworking shop, to experiment with check valves for a wooden body, brass sleeved piston and block water  pump idea I have cooking.

I needed check valves. A rather long google session last night brought no results I was happy with. The concept is a high bypass, therefore low back pressure, check valve for a tiny water pump.

So if it’s not readily available, or at least I can’t find anything suitable (no plastic, if you please), it was time to make them.

I built a prototype, then reworked it to minimize overall length. The result is the inlet side valve that will be glued straight into the maple cylinder head.  Tomorrow I plan on making the outlet side version.

The nitty gritty is as follows:
I mined the telescoping brass tube I have, and began with a tube that is 3/16 OD as the “inner” tube, inlet and outlet. That gave me .160” or so ID. That was perfect for a copper plated common steel BB as a valve ball.
The trick was getting enough bypass to limit back pressure when in “flow” mode.

So to do that, the middle layer, the next size larger tube, was cut to length, and the middle 3/4 or so of it slotted lengthwise, removing roughly half the material, leaving behind a “cage” in the middle section.  The outlet end, opposite the tapered seat the ball will drop into when reverse flow occurs, I cut slots in as well, leaving only the very furthest portion intact. That whole. business  slips inside an outer 1/4OD tube, which forms the check valve body. The overall dimensions are 1/4 OD, x .830” long.  If I were to use it as as an in-line check valve, rather than mounted directly into the block, I’d leave a hose barb on the outlet side as well, making the whole business an inch long. For use pumping water, I used thick CA to assemble the pieces. If and when I build one for the fuel line on the engine, I’ll solder it.

To test it, I attached that spare bit of fuel tubing supplied with the M91 engine, and  by simply drawing water from a cup by mouth, it’s very free when in bypass mode, and slams shut dutifully to prevent back flow, regardless of orientation.

Steam Technology

  • Full Member
  • ***
  • Posts: 309
Re: High bypass check valve for piston water pump build.
« Reply #1 on: September 04, 2020, 02:57:04 am »
Some out of the box thinking here, I like a novel idea. Please show pocs when done.
ALWAYS WORKING TO FIND A CURE FOR CENOSILLICAPHOBIA
Cheers. Dave.

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
Re: High bypass check valve for piston water pump build.
« Reply #2 on: September 04, 2020, 10:00:47 am »
I didnít think of pics as I made the first one.its glued together, so oops!  Iíll show the pieces of the second when I make them.

komet163b

  • Jr. Member
  • **
  • Posts: 207
Re: High bypass check valve for piston water pump build.
« Reply #3 on: September 04, 2020, 11:14:36 am »
Good Afternoon from Brooklyn...

  I've been pondering on how to make a check valve
for my engine-run boiler water pump.  I looked at your
photo and thought, gosh, it would be great to have a
diagram showing the construction.  Any chance you
could do a rough sketch?  Maybe your angle on this
is better than what I've had in mind.  I added a photo
of the parts of my ram - I do not understand how it
could work w/o a check valve.  It's from 1926 - nobody
is left alive who saw it run and it was partly disassembled
when I purchased it.

Thanks,
Wayne

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
Re: High bypass check valve for piston water pump build.
« Reply #4 on: September 04, 2020, 05:19:10 pm »
As requested, a bit of photography to show the innards. I needed to build the outlet side valve anyway, and remembered to do the pic before assembly.

The photo shows, from the top, a block of wood that may serve as integral cylinder and valve head.



Second row down we have the outer valve body barrel. 1/4 OD brass.

Third row down is the middle layer, a cage made by slotting the tube in four places around the middle, leaving intact rings at the ends. The purpose of this bit is to support and position the inside bits, control the ball motion so it stays in its straight line, and allow much more water to psss than would be possible using a straight tube. The slots greatly increase water flow area.

Forth row shows the inlet bit of the innermost layer, with a tapered seat cut for the ball. The BB itself, and the outlet nipple, with the notched skeletonized end facing the ball.  The idea is to maximize available water flow around the ball when it is not seated, yet retain control of the ball travel to insure it will seat, even when used upside dow or sideways. .  The notches in the outlet side allow water to pass the ball, which otherwise would be seated against it, since the design uses no spring.
This end gets a nipple to connect an output hose.

Bottom row is the assembled inlet side version of the valve. The only difference is the inlet side has a hose barb and the outlet side has the barb cut away to allow the body of the valve to be glued into a port drilled in the valve block/cylinder head.

The overall idea is minimum back pressure, maximum flow. That will allow the piston pump to gr tun faster without overloading the system.


Steam Technology

  • Full Member
  • ***
  • Posts: 309
Re: High bypass check valve for piston water pump build.
« Reply #5 on: September 04, 2020, 05:27:45 pm »
Excellent thanks for showing. 8)
ALWAYS WORKING TO FIND A CURE FOR CENOSILLICAPHOBIA
Cheers. Dave.

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
Re: High bypass check valve for piston water pump build.
« Reply #6 on: September 04, 2020, 11:18:54 pm »
No problem.

The next job of course is testing them.

To do that, I bored a hole in a piece of maple to accept a brass tube, and drilled intersecting holes to press fit the valve bodies in place.

For a piston, I plugged one end of a 3/8 inch brass tube with a cork, and used the next larger size for a cylinder liner. Using nothing for piston rings there is of course a fair amount of air leakage, but with that said, using a bit of fuel tubing for a pickup line, i experimented with stroke lengths etc, with a feel for how much effort was applied. Frankly, is almost impossible to feel the water resistance when pulling back the piston or pushing it forward. With no outlet line attached, I managed to miss the kitchen sink a few times, but the pump drained a jelly jar of water with strong squirts, as fast as I could pump it.  The required effort is so little, Iím thinking of extending the stroke length of the pump I have in mind.  The next job is experimenting with piston rings. Iíve got a couple of ideas.

In any event the check valves worked a treat.  If you are going to use them for steam, Iíd want to solder them. For water, thick CA is plenty strong.

Steam Technology

  • Full Member
  • ***
  • Posts: 309
Re: High bypass check valve for piston water pump build.
« Reply #7 on: September 05, 2020, 01:12:44 am »
Great result.
ALWAYS WORKING TO FIND A CURE FOR CENOSILLICAPHOBIA
Cheers. Dave.

komet163b

  • Jr. Member
  • **
  • Posts: 207
Re: High bypass check valve for piston water pump build.
« Reply #8 on: September 05, 2020, 09:47:10 am »
  Thanks for the photo showing the different stages.
I especially liked the pains you took to maximize the
water flow thru your bypass valve. And the BB is a
good alt-use.  I'll take my parts out and ponder
some more.

Thanks,
Wayne

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
Re: High bypass check valve for piston water pump build.
« Reply #9 on: September 07, 2020, 08:23:32 pm »
The thinking on the bypass was a bigger bore isnít great with no spring, as the hall can wander too much. Too tight a middle piece controls the ball, but at speed would create back pressure. Hence the cage insert to control the ball, restricting it to linear travel, while allowing adequate bleed around it.

Steam Technology

  • Full Member
  • ***
  • Posts: 309
Re: High bypass check valve for piston water pump build.
« Reply #10 on: September 08, 2020, 01:16:49 am »
Will this be attached to the line shaft?
ALWAYS WORKING TO FIND A CURE FOR CENOSILLICAPHOBIA
Cheers. Dave.

Adirondack Jack

  • Newbie
  • *
  • Posts: 38
Re: High bypass check valve for piston water pump build.
« Reply #11 on: September 08, 2020, 01:37:54 am »
Perhaps. It May be an alternate use for the engine, or may be located outside the shop itself, perhaps next to the engine. Running it off the line shaft would give me the lower speed input without the need of doing that as part of the pump apparatus.

 

September EOTM Winner:

Trevorís "Bassett-Lowke Steam Generating Plant c1934"