https://www.mhk-engineering.com/-Maschi ... pumpe.html

I have no financial or other interest in this enterprise apart from wishing them well since this could possibly help steam operators out.

Ran through google translate, some terms are probably off, like "delivery medium":

"Boiler feed pump

- Development on our own behalf, at best for a "miniature market niche" -

We had set ourselves the goal of developing a steam-driven piston pump for the boiler feed that meets the following criteria:

Construction sizes from small models to original sizes
A uniform control principle for all sizes
Also in a model version with proportions similar to the original, i.e. no external drivers on the piston rod
Purely pressure-actuated reversal
Simple and economical to manufacture

[Photo caption 1]:
Boiler feed pump, 52 mm high,
Prototype for the development of the control
Made with a long time ago
Lathe, sheet metal caliper and file
[Photo caption 2]:
Boiler feed pump, 574 mm high,
Delivery rate approx. 0.7 L per double stroke
Status: operational

The result of the development is a new type of control that only requires a single control slide.
Conventional, known steam-operated piston pumps have at least two control slides and a correspondingly complex control housing.
Instead of the second control slide, our solution only contains a few very easy-to-manufacture components that only have a minimal effect on the overall manufacturing effort.

The large version is also designed for oil-free operation, so that no contamination occurs and the steam used can be fed back into the feed water without further treatment.

Air pump / compressor

When using the solution as an air pump, significant additional effects must be taken into account.
Since the need for air pumps in the narrow-gauge area is occasionally expressed, the final development for this application is planned for the long term. Without a specific order, the time frame for this is very long. [- See the latest findings here -] [Which says]:

The original development of the reversal was based on an incompressible medium as the delivery medium.
In the later test with (compressible) air as the conveying medium, an effect occurred that unfortunately made uncomplicated use as an air pump practically impossible.
We analyzed this effect purely theoretically and derived a remedy.
This measure then also eliminated the effect, but produced a new undesirable opposite effect which, due to a lack of time in the course of the attempts at that time, could no longer be safely eliminated.

So far there has been the (not ultimately tested) possibility that the latter effect cannot be eliminated in a particularly elegant manner and otherwise entails an externally visible, tendentially unaesthetic additional effort and, moreover, could worsen the efficiency of the pump.

Above all, it would have been difficult to finally determine whether the new effect would have been eliminated in principle or only due to a certain existing constellation of the various influencing parameters. There would therefore be a considerable risk in the event of an order-related design (in an approved version, i.e. with completely different materials and consequently with significantly different design parameters), which would have made commercial follow-up of this development almost impractical.

In October 2015, the previously self-set specifications for the solution for use as an air pump were put to the test again and then relaxed, so that a solution has now emerged that gives the greatest cause for hope for a successful completion of the development. So far, this has only been available as a theoretical concept, but the important aspects can be parameterized on the safe side. We currently estimate the residual risk of failure to be almost zero.

The solution does not require any significant dimensions of the additionally required parts, is quite simple and can therefore be implemented with little effort.

The constructive implementation is planned for 2016. However, depending on access to a test environment, testing under steam may be further delayed. A test with compressed air (on the drive side), however, based on previous knowledge, is likely to have a certain (tendency) informative value.

As soon as further findings are available, we will inform you here.

Thank you so far for your interest!

Your development partner for special solutions in mechanical engineering and hydraulics

[Photo caption 3]:
Execution as a compressor for the supply
the air brakes of rail vehicles
Status: In development [-More-] "

Not sure how many of you want a pump built up out of bar stock.

For us it is a no-go on many fronts. It would require safety and regulatory certification. Our rules are, if it existed under Danish railways service before, it is grandfathered and approved. Anything we do which deviates from historical practice needs certification. So it is much easier from a regulatory framework to rebuild an old pump.

I'm not so concerned about whether is uses castings or rolled steel providing the engineering is sound - castings also fail after all, usually in the steam passage cores behind the steam cylinder first based on my experience. He seems to be doing responsible R&D. Regulations differ too...... the economics are probably more difficult to deal with for acceptance than the engineering, since we've been making machines out of steel for a very long time now. The water pump application is also interesting if it could be adapted to use in a feedwater heater application. Nigel Day's retrofit of one of the Cog's engines showed a very significant decrease in fuel consumption. Of course, this is in the gray area where preservation and sustainable steam converge.

The Chinese were building new steam locomotives into the 1990s. There are a lot of parts still available. Many of them were clones of US designed components. They are also "tried and true" in actual service.

http://www.multipowerinternational.com/parts.html

For some of us, the 9 1/2" compressors are giant. I need something about half that size for our operation.

There are no regulations that would prohibit me from using a smaller steam driven air compressor, so whoever gets a commercially viable product that fits my available space to the market first gets my money! I loathe having to use a Honda driven air compressor for brakes.

Rick, I'm guessing you might have considered this route already, but just in case, have you thought about using a Crown amusement park pump? They were significantly smaller. I'm sure they are not that easy to find and probably not cheap either.

Crown had acquired the effects of WABCO's steam locomotive compressor division in the late 1950's. My grandfather supervised the crating of the patterns, parts and castings that were still in inventory. Crown made compressors and related components until the son sold the business to the Tweetsie in the late 1980's. I don't recall if the air brake part of the business was sold to them also, or if it had already been sold to Bernie Watts http://backshopenterprises.com/aboutus.html

Backshop bought the compressor business from Bert Williams at Crown, and can build you a new pump if you need one....... but multiple options are a nice thing to have available since the Crown pumps are only available in popular WABCO sizes. The Chinese pumps aren't WABCO clones but have significantly different innards, not sure about current availability. Smaller pumps are being developed for limited production in Australia but not yet available, perfect in size for Rick's application.