Nathan double top check boiler feed valve

[phil davis]

thanks so much

[phil davis]

Mine will be fitted to the 800, with the sellers feed water heater, I think from photos they may have had the Nathan top checks before being fitted with the SA type feed water heater. happy to be corrected. I will be doing a drawings for the body, perhaps as just a T piece with commercial checks hidden elsewhere. Will post it up here if anybody wants one when complete.

[Pontiacguy1]

the idea with the top-feed check valves was to feed the water into a perforated trough above the water line, so the incoming water would be heated by steam, rather than mixing cold water into the hot water in the boiler.

I know that the N&W Used a series of horizontal baffle plates in the top of a small auxiliary dome on their M1 class locomotives (the second batch) that was supposed to act like a semi-feedwater heater. The theory was exactly as stated, that the water would have to cascade over a series of hot plates before reaching the boiler water, and it would thus be heated up somewhat. That device and the problematic Walscharts valve gear were the only differences between the M1 and the original M class locomotives. Both items didn't work as intended, especially the flawed Walscharts valve gear on these locomotives. The baffle setup was never tried again on any of the N&W locomotives. Of course, a few years later, true feedwater heaters came out and that was that.

I know that EE was talking about producing them, but I had thought they said this would be project 2 or 3 years down the road. I'd like to get one if someone produced it commercially.

[765nkp]

Brian had them. I think he makes them to order.

[JasonA]

Brian has made them in the past, I have one, but it was very expensive due to the cost of the printed parts.

Jason

[AnthonyDuarte]

the idea with the top-feed check valves was to feed the water into a perforated trough above the water line, so the incoming water would be heated by steam, rather than mixing cold water into the hot water in the boiler.

I know that EE was talking about producing them, but I had thought they said this would be project 2 or 3 years down the road. I'd like to get one if someone produced it commercially.

For what it's worth, I do still plan to make Nathan top feed checks (both styles) in 1.6", but it's unfortunately not very high on the priority list. Check & globe valves, safety valves, and Simplex injectors are currently at the top of the to-do list. Unfortunately there's only one of me, so I can really only work on one project at a time.

I don't believe I ever said 2-3 years. I think 12-18 months would be realistic.

Nathan Top Feed - 2 Injectors Back.JPG (163.25 KiB) Viewed 748 times

Nathan Top Feed - 2 Injectors Front.JPG (180.2 KiB) Viewed 748 times

Nathan Top Feed - FWH INJ Back.JPG (159.87 KiB) Viewed 748 times

Nathan Top Feed - FWH INJ Front.JPG (159.72 KiB) Viewed 748 times

[Greg_Lewis]

So why does the feedwater heater take a different check than the injector?

[AnthonyDuarte]

So why does the feedwater heater take a different check than the injector?

The pump side is a bit more complicated to help reduce losses from the repeated hammering of the check valve. Larger diameter, less valve lift, a longer valve guide, and a spring all help reduce losses every time the valve changes direction. Since the injector delivers a consistent stream, all that extra stuff would hurt more than help.

Nathan Top Feed Check Inject and Pump_fixed.jpg (196.34 KiB) Viewed 695 times

[Greg_Lewis]

Thanks, Anthony.

[phil davis]

thanks for the photos of your 3d model that answers a few questions about shape

[phil davis]

here is my version according to drawings from Norfolk and Western, and other versions commented on here. Bit more work to do.

[apm]

Now is there an affordable shapeways service that anyone has found yet where you can upload these files to and have the parts 3d printed to wax and then investment cast?

After seeing the work others are doing with 3D printing and investment casting online I am wondering if anyone is offering the whole thing as a service yet? Last time I had something like that quoted with shapeways it came back at stupid money and then others who have actually used the service report that the 3D printed and cintered parts they are receiving back can't even be threaded without destroying taps.