Help with 'Speedy' valve gear and other issues...

[Roger]

Slow progress, but I have managed to get some detail design of the overflow valves and outlet.

I'll Sliver Solder the inlet water and outlet water pipes directly into the body. The inlet steam will be a union connection.

I've actually shown it upside down, the overflows are on the bottom to simulate the way they will be on the final scale injector.

The One Piece test cone will have an additional O-ring to separate the two overflows.

Test injector assembly by Roger Froud, on Flickr

[Roger]

Just a quick post to wish you all a Happy New Year and hope that you're safe and well. It's your continued interest and support that keeps me going when I might otherwise lose interest. Knowing that you're here makes a huge difference, and I want you to know how important it is to me. Sharing the trials and tribulations of designing and making things is so much better than trying to do these things in isolation. This past year has necessarily driven us into isolation, so coming here for inspiration and support helps more than you might imagine.
Anyway, let's hope 2021 turns the corner with this awful virus and sets us on the path to something like we had before.

Roger

[92220]

And a Happy New Year to you too Roger. And 'Thank you' for a really interesting, informative and instructional, build diary.

Bob.

[Roger]

I think this is about finished now. The idea is to allow for slightly different lengths of test cones to be clamped in position. The LH outlet end has a long O-ring pocket so it can seal whatever the position of the plug. I've provided a proper location on both sides of the O-rings throughout where I know it will be dismantled many times. Usually I just use the thread to pull the O-ring out because I can always change it if it's damaged. I don't want to keep doing that in this case.

This is the way up it's intended to be used. I'll Silver Solder the water inlet and outlet pipes into their locations. 

I've used a M7 x 0.5 (fine) thread on the Steam Cone to make the adjustment fine. It's possibly to adjust the Steam cone so that there's no gap at all.

The Bronze coloured piece is screwed up to the Hex head which serves at the stop.


Test injector finished assembly by Roger Froud, on Flickr

Anyway, I'll create 2D drawings for the parts since there are so many dimensions required to make it. Then I can crack on with it.

[delaplume]

Nil Desperadum old chap.....keep the faith, and pass the ammunition !!


Don't "Poo-pooh" your efforts}----------   www.youtube.com/watch?v=QeF1JO7Ki8E  ---------

[jon38r80]

Cant say I even vaguely understand the this other than it works a bit like the old two tube mouth sprayers I used to use for spraying dope onto model aircraft, but as usual your approach to the manufacture and attention to detail is fascinating

[Roger]

Jan 1, 2021 13:46:14 GMT jon38r80 said:

Cant say I even vaguely understand the this other than it works a bit like the old two tube mouth sprayers I used to use for spraying dope onto model aircraft, but as usual your approach to the manufacture and attention to detail is fascinating

Hi Jon,
It looks more complex than it is when viewed in section. When the pieces are made and laid out, it will be much clearer. It would have been much simpler to have attached the Steam in and Water out connections at the ends, but that would have meant dismantling it to adjust the Regulation gap and changing the cones.

I've taken this more convuluted approach to make those things easy, at the expense of more complexity.

[Gary L]

Dec 31, 2020 21:37:36 GMT Roger said:

Slow progress, but I have managed to get some detail design of the overflow valves and outlet.

I'll Sliver Solder the inlet water and outlet water pipes directly into the body. The inlet steam will be a union connection.

[Snip]

Is that a good idea Roger? Conventional injectors have those flat-faced olives on all the pipe joints, which I’ve always assumed are to make it easy to remove the injector for cleaning- which some people do after every run. If you make it difficult to service your injectors, you might wish someone had warned you -?

HTH

Gary

[Roger]

Jan 1, 2021 14:50:44 GMT Gary L said:

Dec 31, 2020 21:37:36 GMT Roger said:

Slow progress, but I have managed to get some detail design of the overflow valves and outlet.

I'll Sliver Solder the inlet water and outlet water pipes directly into the body. The inlet steam will be a union connection.

[Snip]

Is that a good idea Roger? Conventional injectors have those flat-faced olives on all the pipe joints, which I’ve always assumed are to make it easy to remove the injector for cleaning- which some people do after every run. If you make it difficult to service your injectors, you might wish someone had warned you -?

HTH

Gary

Hi Gary,
This is only for the Test Injector body, the scale ones have got flanges. However, the intention is to service the final Injector by removing the cones and spacers, leaving the body in place. This is totally impractical with conventional designs, but easy to do with this type where the cones are a slide fit with 'O' rings for seals.

[don9f]

Echoing the good wishes of others, I find hardly a day goes by in my workshop these days without something I’m doing, or using makes me think of you (don’t take this the wrong way!). As examples, I’ve just been using pcb drills again on one job and milled out some pieces from flat sheet on another today (done by coordinates though, no cnc!).
Thanks for these and all the other good ideas I’ve learned from your thread.....

Cheers & Happy New Year       Don

[Roger]

Thanks for that Don, I'm pleased I can give a little back for all the help I've received over the years.

It's a bit chilly, even in my heated workshop today, so I've taken a break for a few hours. Hopefully I'll do a bit more later.

This is one end of the Test Injector Body completed, that now needs the holes in the top and bottom adding on the mill.

20210101_173355 by Roger Froud, on Flickr

And this is the Steam Cone which is made as part of the adjusting screw. I was going to make this with an M7 x 0.5 (fine) thread, but I've been supplied with the right 2nd tap but a 0.75mm pitch Bottom tap instead. I'll sort that out on Monday, but I want to crack on with this, so I've changed the design to use 0.75mm pitch instead.

This also needs cross holes to be added on the mill as well as the Hex on the end.

20210101_173043 by Roger Froud, on Flickr

I'll make the other parts on the lathe first and then do all of the milling operation in one go. That won't take long, I've already created the bulk of the programs.

[Roger]

This is the middle part at the Steam Cone end. The water is going to go through holes in the groove where the thread is, and the Steam will go through holes up next to the flange on the left.

20210101_214026 by Roger Froud, on Flickr

Time for a 'sanity check' to make sure the parts fit together properly without O-rings at least.

20210101_213946 by Roger Froud, on Flickr

[Roger]

This is the 13 degree tapered reamer being ground in half after grinding the angle. It's just a piece of 4mm Silver Steel this time instead of HSS since I didn't have any in that size.


20210102_153625 by Roger Froud, on Flickr

That was hardened and tempered. This is for the back end of the Steam Cone. I'm not convinced it needs a tapered entry, but it's getting one to be on the safe side.

20210102_154657 by Roger Froud, on Flickr

All of the 4th Axis jobs were done while it's set up. This is the Steam Cone getting the feed holes in the side...

20210102_112644 by Roger Froud, on Flickr

... and this is the middle plug getting the same and also the water holes. The keen eyed will have spotted that I missed one of the Steam holes in the row at the back. I could spot that through from the other side now it's been taken out of the chuck, but I probably won't bother since there are way more than I need.

I've now created a series of little programs called A6,A8, A12.nc etc which just has a list of A0,A30,A60,A90 commands for example so I can just single step between them for common divisions. Then I won't forget one!

20210102_120845 by Roger Froud, on Flickr

While I was looking for the right size PCB drill for the water way holes, I came across a 6.4mm drill and a 0.1mm one. I thought I'd put them side by side so you can see the range of sizes available. You can get every increment of 0.05mm in between.
You can see that in the smaller sizes, they step down so as to keep broadly the same setting length from the end of the Carbide shank to the tip. On PCB machines, the tools are usually picked up and then set to the right length in software using a laser. They can also be checked after they've been used to see if they broke.
The 6.4mm drill has that very shallow angle I mentioned before which stops it breaking through the exit material.

20210102_171221 by Roger Froud, on Flickr

Anyway, this is the bottom of the body getting the two ports machined for the overflows and the smaller one for the Steam inlet union.

20210102_145356 by Roger Froud, on Flickr

There's a deep slot in both so that it doesn't take up any more room in the body than necessary. That will enable me to get a third O-ring between them on the One Piece Cone.

I'm using a very long 1.5mm cutter with only 0.1mm cuts at a time because it's very fragile. I can't reach with a standard length cutter but I had these from another job.

20210102_170037 by Roger Froud, on Flickr

The top side has the Steam inlet on the left and the pocket for the outlet pipe to be Silver Soldered on the right.

20210102_171612 by Roger Froud, on Flickr

Then it was on to adding the Hexagons on the ends...

20210102_174456 by Roger Froud, on Flickr



20210102_211740 by Roger Froud, on Flickr

... then making the Steam inlet union...

20210102_214100 by Roger Froud, on Flickr

... which also needed a hex.

20210102_214513 by Roger Froud, on Flickr

I've been pretty lazy today, so I didn't get much done. however, this is the progress to date, so I'm getting there.

20210102_221243 by Roger Froud, on Flickr

[chris vine]

Hi Roger,

That is a fab research tool you have made! With your ease of making very accurate parts, I wonder if the taper angles which are prescribed in the known designs are correct?
If you can get something which works, then maybe you could try some different angles in the cones. Unless, of course, you have already calculated them by mathematics....

Chris.

[Roger]

Jan 2, 2021 22:53:17 GMT chris vine said:

Hi Roger,

That is a fab research tool you have made! With your ease of making very accurate parts, I wonder if the taper angles which are prescribed in the known designs are correct?
If you can get something which works, then maybe you could try some different angles in the cones. Unless, of course, you have already calculated them by mathematics....

Chris.

Hi Chris,
Hopefully it will be worth the effort and reveal what's going on more easily.

A lot of work has already been done on the angles, with the current ones being in the middle of the workable range. You can go a degree either side of the norm if you want to alter the length of the cones. What's important is to make the angles exactly to the design values because the throat sizes and ratios are important.

What I'm trying to investigate is whether it's feasible to make three cones in one with drill ways instead of gaps. I'm also trying to find out if it's possible to use just one overflow valve for both gaps. Hopefully this will enable be to tie those things down and give a definitive answer. That will steer what I have to do to make cones that fit the scale 8x body or what needs to give.

[delaplume]

Loving all this !!

PS}--- could you give me the name of your optician ??.......LoL

[jma1009]

Hi Roger,

Forgive me please, but what are your 3 throat sizes, and if you can convert them to imperial for me I would be most grateful.

I believe you are doing a 16 oz per minute delivery output if my memory is correct?

Stunning work as always and I think you are on the right 'track'' with the test injector body with an O ring between the 2 check valves to separate them.

Cheers,
Julian

[Roger]

Jan 3, 2021 19:45:08 GMT jma1009 said:

Hi Roger,

Forgive me please, but what are your 3 throat sizes, and if you can convert them to imperial for me I would be most grateful.

I believe you are doing a 16 oz per minute delivery output if my memory is correct?

Stunning work as always and I think you are on the right 'track'' with the test injector body with an O ring between the 2 check valves to separate them.

Cheers,
Julian

Hi Julian,
Yes, that's right, it's a 16Fl Oz/min size. I've taken the throat sizes from Table 2 on page 30 of Bob Bramson's book which are as follows...

Steam Cone 20-80PSI 0.043" 30-100PSI 0.037" so I've taken the middle value of 0.04" since I'm going up to 90PSI
Combining Cone 0.032"
Delivery Cone 0.026"

I think it's essential to know what's happening on both of the overflows otherwise it's going to be really hard to diagnose. I'm not that hopeful that it will work with just a common overflow valve to be honest. It's going to be a real challenge to fit it in the body if that's the case. I'm not sure it would be possible, but we'll cross that bridge when we come to it.

[Roger]

Time to do all of the internal operations on the various parts.

Here I've checked the length of the bottom tap and subtracted the depth of thread required so I can avoid hitting the bottom of the shoulder which isn't much smaller than the tapping size.

20210103_122334 by Roger Froud, on Flickr

The body has been clocked up and used to hold the next piece I need to machine.

20210103_124158 by Roger Froud, on Flickr

The deep rear taper for the Steam Cone is set the same way as the main cones. I've left about 0.5mm of parallel throat in the Steam cone. I don't see the point in trying to make the tapers meet at precisely the right diameter.

20210103_154931 by Roger Froud, on Flickr

This is the inlet Steam Union being turned to be a press fit in the shallow location pocket.

20210103_162556 by Roger Froud, on Flickr

And this is the closing cap on the delivery end getting its drillways for the water exit path.

20210103_190111 by Roger Froud, on Flickr

A quick sanity check that the closing bung on the Steam Cone end fits as it should.

20210103_195843 by Roger Froud, on Flickr

The delivery cone end bung then got its hex. It's a fairly delicate thread I can't do up that tightly, so I only took 0.2mm deep cuts to make sure it didn't unscrew while being machined.

20210103_201751 by Roger Froud, on Flickr

The chamfer was added and that's another part done.

20210103_202840 by Roger Froud, on Flickr

This is how it looks at the end of play today. All of these parts are complete.

20210103_205024 by Roger Froud, on Flickr

I've started on the overflow valve bodies and then I still have the closing caps to make and the exit tubes.

[jma1009]

Hi Roger,

Thanks for the reply. Your throat sizes are to proven sizes.

You might, for testing like to go down a size on the steam cone throat, just a few thou, to get your upper range - you can always open out the throat of this if I am wrong.

You could also go up a few thou on the end of the combining cone throat as part of a vigorous and methodical testing regime.

You could separate the delivery cone from the combining cone in your test body - and I personally would not rule out the traditional press or very close sliding fits if appropriate to design.

Concentricity is absolutely paramount throughout.

Cheers,

Julian