jma1009
Elder Statesman
Posts: 5,922
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Post by jma1009 on Jan 27, 2021 22:34:23 GMT
Hi Roger,
Are you monitoring the temperature of the feed water exiting the injector? And if so what are the results, please?
And say the top pressure feed to determine the exact range?
Cheers,
Julian
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Post by Roger on Jan 27, 2021 23:25:36 GMT
Hi Roger, Are you monitoring the temperature of the feed water exiting the injector? And if so what are the results, please? And say the top pressure feed to determine the exact range? Cheers, Julian Hi Julian, I haven't been measuring that directly, but I know the collection container gets up to about 55C by the time I've checked it. I see that D.A.G Brown uses the temperature to check the regulation, and that's something I need to do now I've got something that needs a bit more refinement. He says that the temperature should be between 65-70C, but without telling you what the feed water temperature is. He does give figures for the extremes of temperatures, 10C in gives 65C out, and 40C in gives 95C out, so it looks like the expected temperature ought to be 55C above whatever water temperature I'm using. Up until now, it's been more a case of homing in on something that works rather than getting the finished setup optimised. It's interesting to see what happens when you increase the regulation gap from zero. You just get steam out of the overflow until the regulation gap is quite close to the working range. Then it picks up, but it's not stable and the outlet pressure isn't at a maximum. Increasing the gap a little more gets the outlet pressure at a maximum, and it stays like that if you increase the gap a little more. However, if you continue to increase the gap, the outlet pressure drops back and eventually it just stalls. When you say the top pressure feed, I presume you mean the highest pressure I test up to? I don't go beyond 95psi because I don't need to. I will try the injector with the larger size of throat though, to see if it will still work at that pressure. If it's happy, then it ought to work better at lower pressure with the bigger nozzle. I suppose I ought to make an even larger Steam Cone if it's still happy, just to find out where the limit is. |
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jma1009
Elder Statesman
Posts: 5,922
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Post by jma1009 on Jan 28, 2021 0:09:14 GMT
Your last sentence, Roger, in your last above post, accords with my own reasoning!
Fascinating stuff!
Cheers,
Julian
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Post by Roger on Jan 28, 2021 8:38:14 GMT
Your last sentence, Roger, in your last above post, accords with my own reasoning! Fascinating stuff! Cheers, Julian What tests do you usually perform? I don't think tests with cold water, say less than 20C tell you much, I'm inclined to check at 20C and again at 30C. |
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Post by chris vine on Jan 28, 2021 11:29:37 GMT
Hi Roger,
Gosh, you are making amazing progress. The ability to make these intricate cones and then test them so quickly with an adjustable regulation gap is a huge leap forward.
I know you are not interested in mass production, but a reliable injector which can work with warm water would be the foundation an a good small business...
With your excellent machining capabilities, do you think you could make the cones out of something tougher than brass (once you get an optimised design). It would be lovely to think that one of your injectors will still work in 100 years time...
Chris.
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Post by Roger on Jan 28, 2021 11:50:58 GMT
Hi Roger, Gosh, you are making amazing progress. The ability to make these intricate cones and then test them so quickly with an adjustable regulation gap is a huge leap forward. I know you are not interested in mass production, but a reliable injector which can work with warm water would be the foundation an a good small business... With your excellent machining capabilities, do you think you could make the cones out of something tougher than brass (once you get an optimised design). It would be lovely to think that one of your injectors will still work in 100 years time... Chris. Hi Chris, I'm certianly getting somewhere. I just need to get to the point where I'm convinced that they perform at least as well as conventional one. The claims D.A.G Brown makes about some running down to 15psi makes me think there's a long way to go. However, it might just be that this only happens when using cold water, and that makes a huge difference. Making the cones from something else isn't a big problem. What are your concerns about Brass? The obvious one is dezincification, so a Bronze would solve that one. I'm planning on making mine from SAE660 Leaded Bronze which is as easy to machine as Brass. Is erosion a big issue, and is that only associated with Brass cones? At the moment I'm just concerned with making these for the scale injectors, I don't really want to get into making a business out of it. Even if there's money to be made, it's boring doing the same thing time and time again. I'm not sure there's enough money in it to be worth the effort, with all the pain of having to deal with customers who expect them to work even when the installation is actually at fault. Maybe one day I'll change my mind, but for the moment I can't see it happening. |
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Post by chris vine on Jan 28, 2021 12:35:42 GMT
Hi Roger,
I totally understand that "mass" production with people complaining that your injectors don't overcome their own deficiencies is not to your liking!!
My comment about the material for the cones comes from experience with injectors which have worked perfectly for some years and then become poor and then useless. I have always reckoned that it is the steam cone wearing, however this might be because of cleaning the cones/injectors in citric acid for too long. I have certainly had steam cones (with the annular regulation with very thin ends to the steam nozzle) which have become paper thin - actually Paper is probably thicker - then they crack/bend and the injector fails.
So, I haven't measured the steam cone throat because it is difficult and I don't know what it was when new!!
My feeling is that brass is a poor material compared to a proper bronze.
Maybe when you have a reliable injector (or even just a developed set of cones in your test injector, you could leave your electric test boiler running on an extended test and see if there is any wear on the cones. I am pretty sure that no one has ever done that before. It would certainly get boring to keep putting coal on the fire...
all best
Chris
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Post by Roger on Jan 28, 2021 13:24:29 GMT
Hi Roger, I totally understand that "mass" production with people complaining that your injectors don't overcome their own deficiencies is not to your liking!! My comment about the material for the cones comes from experience with injectors which have worked perfectly for some years and then become poor and then useless. I have always reckoned that it is the steam cone wearing, however this might be because of cleaning the cones/injectors in citric acid for too long. I have certainly had steam cones (with the annular regulation with very thin ends to the steam nozzle) which have become paper thin - actually Paper is probably thicker - then they crack/bend and the injector fails. So, I haven't measured the steam cone throat because it is difficult and I don't know what it was when new!! My feeling is that brass is a poor material compared to a proper bronze. Maybe when you have a reliable injector (or even just a developed set of cones in your test injector, you could leave your electric test boiler running on an extended test and see if there is any wear on the cones. I am pretty sure that no one has ever done that before. It would certainly get boring to keep putting coal on the fire... all best Chris Hi Chris, At least I won't have to worry about the Steam Cone end, that's a stubby flat affair because I'm using End Regulation as championed by Bob Bramson. Since this is such an ovbious design deficiency, I'm suprised that everyone else seems to use Annular Regulation. I guess they have designs that work, so they aren't inclined to change them. However, those wafer thin cones aren't the easiest to make accurately either. I can see why people don't want to get involved with making injectors, it's just a pain when there are four separate cones. Ideally, I'd like to come up with a design that anyone can make without having to worry too much about concentricity and press fits. I can't see why people can't make them, take them apart and put them together again routinely. I intend to leave the body in place on the Locomotive and just take the cones out if it needs attention. That overcomes the issue of having to deal with tiny flange bolts on scale bodies. There's no reason why there can't be more rudimentary body though, for those who aren't interested in a scale appearance. I'll probably stick with SAE660 for the cones, I can make half a dozen spares in case they do wear. I think you'd have to keep an injector running for months before you saw any degradation, so I'm not sure how practical the experiment would be. In an industrial setting that wouldn't be an issue. |
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milky
Seasoned Member
Posts: 122
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Post by milky on Jan 28, 2021 13:36:42 GMT
Roger, Hats of to you and the R&D. I would say an injector operating below 40psi is pretty usless in real operating conditions (for this application) What I would be interested in seeing is could you get them running at higher psi and does the design scale for different flow rates. You know for a say a 10 1/4" gauge running at 120-150 psi  Another variable is hard and soft water (not sure if you have covered this). In the past this has been an issue for us Lancashire water nice and soft, down in the south east hard to very hard. Hard water deposit build up seems to do the most damage to cones Would aluminum bronze work.. |
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Post by Roger on Jan 28, 2021 15:19:28 GMT
Roger, Hats of to you and the R&D. I would say an injector operating below 40psi is pretty usless in real operating conditions (for this application) What I would be interested in seeing is could you get them running at higher psi and does the design scale for different flow rates. You know for a say a 10 1/4" gauge running at 120-150 psi Another variable is hard and soft water (not sure if you have covered this). In the past this has been an issue for us Lancashire water nice and soft, down in the south east hard to very hard. Hard water deposit build up seems to do the most damage to cones Would aluminum bronze work.. Hi Philip, Agreed, 40psi and less isn't of much interest for practical use. It does act as a good indicator of how well proportioned the Injector is though. You can make these run at any pressure, all you have to do is reduce the diameter of the Steam Cone throat. There's no reason why you can't replicate this style of injector in any size. However, it would take a fair bit of development. I suppose build up is going to be an issue in hard water areas, since it's hot and water is going to evaporate on the surface of the cone. I harbour a wish to make a cone from Fluorosint, just to see if it's possible. The idea being that it might resist disolved solids from sticking to it. However, it would be easily damaged, so maybe it would end up getting abraded by the action of the steam. You could use Aluminium Bronze, Stainless Steel or Phosphor Bronze. All of these take their toll on the reamers, but if you're not making many then that's not a big problem. I guess you would have less abrasion, but solids building up on them will still happen. |
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Post by Roger on Jan 28, 2021 18:46:19 GMT
Slow progress today because I've been doing a rare commercial job. However, here's another variant on the most promising cone design so far. This is identical to the previous iteration with the exception of the position of the second row of holes which are much closer to the first row.  Cone19 by Georgia Montgomery, on Flickr Following up on Julian's point about measuring temperatures, here's the new setup. I bought this dual channel meter for another project but it's ideal for this one because it can display the difference between the two probes.  20210128_171619 by Georgia Montgomery, on Flickr This is the probe on the delivery outlet pipe before adding any Silicone Grease to conduct the heat...  20210128_095158 by Georgia Montgomery, on Flickr ... and this is the one on the feed water pipe.  20210128_095208 by Georgia Montgomery, on Flickr There's a small offset which is only to be expected.  20210128_095232 by Georgia Montgomery, on Flickr I also received these Silicone rubber LED covers today, and they're really soft. I could definitely see these being used for a valve. I'll just have to figure out an arrangement to hold them. They're clearly too long, but it's easy enough to trim them down a bit. I don't think there's room to just use them with a spring up the middle. That would be an elegant solution.  20210128_132525 by Georgia Montgomery, on Flickr |
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Post by chris vine on Jan 28, 2021 19:36:08 GMT
Hi Roger,
I think the benefit of having a range of operating pressures beyond what you require is that you have a margin for the injector to change or deteriorate over time and expect it still to work.
I have noticed (Bongo runs at 120 psi) that if an injector only just works at the full blowing-off pressure, it isn't long before it starts to misbehave. Remember, I used to operate Bongo for 8 hours a day at exhibitions, so put a fair amount of water through them. Mind you, maybe no more than used in an hour's hard running at a club track day!
Chris.
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Post by 92220 on Jan 28, 2021 19:49:21 GMT
Roger, Hats of to you and the R&D. I would say an injector operating below 40psi is pretty usless in real operating conditions (for this application) What I would be interested in seeing is could you get them running at higher psi and does the design scale for different flow rates. You know for a say a 10 1/4" gauge running at 120-150 psi Another variable is hard and soft water (not sure if you have covered this). In the past this has been an issue for us Lancashire water nice and soft, down in the south east hard to very hard. Hard water deposit build up seems to do the most damage to cones Would aluminum bronze work.. Hi Philip, Agreed, 40psi and less isn't of much interest for practical use. It does act as a good indicator of how well proportioned the Injector is though. You can make these run at any pressure, all you have to do is reduce the diameter of the Steam Cone throat. There's no reason why you can't replicate this style of injector in any size. However, it would take a fair bit of development. I suppose build up is going to be an issue in hard water areas, since it's hot and water is going to evaporate on the surface of the cone. I harbour a wish to make a cone from Fluorosint, just to see if it's possible. The idea being that it might resist disolved solids from sticking to it. However, it would be easily damaged, so maybe it would end up getting abraded by the action of the steam. You could use Aluminium Bronze, Stainless Steel or Phosphor Bronze. All of these take their toll on the reamers, but if you're not making many then that's not a big problem. I guess you would have less abrasion, but solids building up on them will still happen. Hi Roger. I did wonder if stainless could be used for the cones. It would probably be the longest lasting material. You comment that the reamers wouldn't stand up to it for long, before degrading. You use a lot of carbide cutters, and you make your own reamers for the cones. Could you not make the reamers out of old carbide cutters? Surely that wouldn't be too difficult with a diamond grinding wheel. Not having any experience of grinding carbide, I am prepared to be 'shot down'. Bob. |
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Post by chris vine on Jan 28, 2021 20:04:33 GMT
I didn't mean to make your challenge even more difficult.
We need to let Roger walk before we ask him to fly to the moon!!
Chris.
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Post by Roger on Jan 28, 2021 20:45:13 GMT
Ok, that wasn't very clever, I should have modified the 5 hole per row version, not the 4 hole. In any case, I went back and re-tested the 5 hole version and compared it to the best single row cone, and found that the single row one was actually better. So this is the best of the two row cones, modified to make the second row of holes 0.6mm instead of 0.5mm. The single row injector has a sharper pick up and drop out characteristic, and that might just be because there's a little more overflow area. I could have gone up to 0.55mm on the second row, but I thought I'd try this first.  Cone20 by Georgia Montgomery, on Flickr The differential temperature reading was about 55C when it had settled down feeding the boiler. Unfortunately, the Balanced Clack valve makes the flow more unstable, and that results in the overflow being considerable. To be honest, I'm not sure why D.A.G Brown thinks this is such a useful tool. If the overflow is completely dry, I can't see how the temperature can be that far out. |
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Post by Roger on Jan 28, 2021 20:47:20 GMT
Hi Roger, I think the benefit of having a range of operating pressures beyond what you require is that you have a margin for the injector to change or deteriorate over time and expect it still to work. I have noticed (Bongo runs at 120 psi) that if an injector only just works at the full blowing-off pressure, it isn't long before it starts to misbehave. Remember, I used to operate Bongo for 8 hours a day at exhibitions, so put a fair amount of water through them. Mind you, maybe no more than used in an hour's hard running at a club track day! Chris. Hi Chris, That's a fair point. Hopefully, being able to take the injectors apart so easily will mean that servicing and inspecting them ought to be easy. |
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Post by Roger on Jan 28, 2021 20:50:50 GMT
Hi Philip, Agreed, 40psi and less isn't of much interest for practical use. It does act as a good indicator of how well proportioned the Injector is though. You can make these run at any pressure, all you have to do is reduce the diameter of the Steam Cone throat. There's no reason why you can't replicate this style of injector in any size. However, it would take a fair bit of development. I suppose build up is going to be an issue in hard water areas, since it's hot and water is going to evaporate on the surface of the cone. I harbour a wish to make a cone from Fluorosint, just to see if it's possible. The idea being that it might resist disolved solids from sticking to it. However, it would be easily damaged, so maybe it would end up getting abraded by the action of the steam. You could use Aluminium Bronze, Stainless Steel or Phosphor Bronze. All of these take their toll on the reamers, but if you're not making many then that's not a big problem. I guess you would have less abrasion, but solids building up on them will still happen. Hi Roger. I did wonder if stainless could be used for the cones. It would probably be the longest lasting material. You comment that the reamers wouldn't stand up to it for long, before degrading. You use a lot of carbide cutters, and you make your own reamers for the cones. Could you not make the reamers out of old carbide cutters? Surely that wouldn't be too difficult with a diamond grinding wheel. Not having any experience of grinding carbide, I am prepared to be 'shot down'. Bob. Hi Bob, You're absolutely right, you can buy Carbide drill blanks just like you can HSS ones, so you certainly can make them out of Carbide. How fragile they would be is a big question. To be honest, sharp HSS ones ought to be ok, but until I've tried it I won't know. Carbide isn't hard to grind with the right wheel. I've got a green grit wheel that would do the job. We'll see. |
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Post by Roger on Jan 28, 2021 22:24:08 GMT
Ok, that last test wasn't noticeably different from the previous best two row Cone, so at the moment, this single row version is the best. It has 10 x 0.6mm holes for the Combining Cone overflow and 5 x 0.5mm holes for the Delivery Cone overflow. Now that it seems that a single row is better than a two row (or more), I'll see if minor adjustments can improve on this design. I need to do some more tests on this one to explore the limits. It currently picks up and restarts when the water is turned off, and runs dry from 90psi to 45psi without dribbling. I could probably home in on an optimum gap with a bit of experiment.  Cone15 by Georgia Montgomery, on Flickr |
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Gary L
Elder Statesman
Posts: 1,208
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Post by Gary L on Jan 29, 2021 0:06:21 GMT
Roger, Hats of to you and the R&D. I would say an injector operating below 40psi is pretty usless in real operating conditions (for this application) What I would be interested in seeing is could you get them running at higher psi and does the design scale for different flow rates. You know for a say a 10 1/4" gauge running at 120-150 psi Another variable is hard and soft water (not sure if you have covered this). In the past this has been an issue for us Lancashire water nice and soft, down in the south east hard to very hard. Hard water deposit build up seems to do the most damage to cones Would aluminum bronze work.. Hi Philip, Agreed, 40psi and less isn't of much interest for practical use. It does act as a good indicator of how well proportioned the Injector is though. You can make these run at any pressure, all you have to do is reduce the diameter of the Steam Cone throat. There's no reason why you can't replicate this style of injector in any size. However, it would take a fair bit of development. I suppose build up is going to be an issue in hard water areas, since it's hot and water is going to evaporate on the surface of the cone. I harbour a wish to make a cone from Fluorosint, just to see if it's possible. The idea being that it might resist disolved solids from sticking to it. However, it would be easily damaged, so maybe it would end up getting abraded by the action of the steam. You could use Aluminium Bronze, Stainless Steel or Phosphor Bronze. All of these take their toll on the reamers, but if you're not making many then that's not a big problem. I guess you would have less abrasion, but solids building up on them will still happen. It might stop the fur build-up, but unless it stops it 100% and guaranteed, some of us will always continue the habit of a regular bath in citric, so in view of the disadvantages of using a plastic it might be an experiment too far. (Not that it will stop you!). Much more productive (IMHO) to build on your easy-release principles which makes the acid bathing easier to do. We are likely to have to continue regular descaling of boilers & boiler fittings in any case. I’m so pleased that your experiments are going so well. Even if you don’t get an actual improvement in performance, your redesigned cones offer the benefits of much more consistency in manufacture and the possibility of marketing injectors with interchangeable cartridges that can be tailored more exactly to different operating environments. Significant advances! Gary |
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Post by Roger on Jan 29, 2021 9:35:22 GMT
Hi Philip, Agreed, 40psi and less isn't of much interest for practical use. It does act as a good indicator of how well proportioned the Injector is though. You can make these run at any pressure, all you have to do is reduce the diameter of the Steam Cone throat. There's no reason why you can't replicate this style of injector in any size. However, it would take a fair bit of development. I suppose build up is going to be an issue in hard water areas, since it's hot and water is going to evaporate on the surface of the cone. I harbour a wish to make a cone from Fluorosint, just to see if it's possible. The idea being that it might resist disolved solids from sticking to it. However, it would be easily damaged, so maybe it would end up getting abraded by the action of the steam. You could use Aluminium Bronze, Stainless Steel or Phosphor Bronze. All of these take their toll on the reamers, but if you're not making many then that's not a big problem. I guess you would have less abrasion, but solids building up on them will still happen. It might stop the fur build-up, but unless it stops it 100% and guaranteed, some of us will always continue the habit of a regular bath in citric, so in view of the disadvantages of using a plastic it might be an experiment too far. (Not that it will stop you!). Much more productive (IMHO) to build on your easy-release principles which makes the acid bathing easier to do. We are likely to have to continue regular descaling of boilers & boiler fittings in any case. I’m so pleased that your experiments are going so well. Even if you don’t get an actual improvement in performance, your redesigned cones offer the benefits of much more consistency in manufacture and the possibility of marketing injectors with interchangeable cartridges that can be tailored more exactly to different operating environments. Significant advances! Gary Hi Gary, You're probably right about still needing to de-scale. One thing I haven't really considered is scale building up either side of the O-rings. It might be prudent to smear a thin film of Silicone Grease onto the inside surface of the body to help with that. Since it's so easy to take the cones out, they could be removed regularly, even after each run. If you took the cones out then they probably wouldn't need de-scaling. I think the problem is that a significant amount of water remains inside the body when the Locomotive is stored, and all of that will evaporate, leaving behind the dissolved solids. I think what I've got is already usable, I'm just comparing the performance claimed in D.A.G Brown's book, and it definitely falls short of that. I am of course presuming that he's being completely honest. |
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