Here at Rungsted Kyst, Denmark, I was discussing some work on our boiler check valves on K 582.

The "K" has a valve body that integrates a plug cock shutoff on the boiler side with a vertical check valve. Apparently, the performance of these check valves is a big problem and something to watch while underway. They frequently experience stuck valves, and someone has to climb out on the running board (!) while running, grab the wrench carried on the running board for this purpose, and close the plug valve. I am not sure how much I believe that last one, but I have seen running board walking decades ago in the USA.

A couple of points. First, I don't ever recall check valves being a big problem in the USA. Is this a design issue, a maintenance issue, or a water issue? The plug valve and the big wrench kept for this purpose on the running board tells me that historically this has been a problem in Denmark.

Second, and why this came up, they have a hard time refitting these plug cocks. The valve body has four channels lengthwise of the plug that in the past were filled with an asbestos-rubber putty that helped to lubricate and seal the plug. That compound is no longer available, and now they are using graphite rope. It does not last, and the valve quickly starts to leak.

Their normal practice is to close these plug valves whenever banking the engine for the night. So the valves need to work. Again, I don't recall ever touching check valves in USA practice.

Anyone ever seen a plug valve design like this, and I wonder why the valve is not metal to metal? Any ideas on how to overhaul these valves?

Plug cocks, no......but I generally shut off the valves in the feed line just outboard of the check valves as SOP when banking. I have found locomotives sitting in a steaming puddle of warm water on a cold morning with slugs of water running out of the overflow pipes, listening to the checks cycle open and closed due to vacuum cycles in the cooling boiler otherwise. This may not be the case with top feeds, we're overhauling one with top feeds now and perhaps it will be more forgiving.

The integral valves I have seen were screw valves which push a disc against a seat beneath the check valve. Real old style fittings might be different.....Chris deWitt would be the go to guy about that.

We generally hammer stuck check valves until they seat. Wrenches make good hammers. It also helps with the frustration involved. One solution that is not original would be to leave the plug cocks open, and add a separate standard steam rated valve just outboard of the valve/check fitting, using it to do the work. Also, I think it was Texas State that developed a retrofit Teflon seal for their checks about 15 years ago. They may have some useful advice for you.

Good luck - let us know how everything is working out there. Regards to Ophelia.

dave

Found this photo, and clipped a closeup of the valve. You can see the wrench in its running board storage mount. The plug valve is behind the check valve.

Oh by the way, see those oiling points on the valve gear hanger? Those are wooden plugs sealing the holes. The holes are threaded, and maybe a long time ago there were metal plugs, but they are all wood now. And, we carry a supply of replacements for when they fall out on the road.

Did I mention this engine runs in traffic at 60 mph?

Hey Dave,
The method of hammering has definitely proven to be practiced! One look at both valve bodies, and all of our spares, show signs of being beat on many times throughout their lives. The practice with the valves is to always turn the valve clockwise to help prevent the yarn from being torn by reversing the rotation. When banking the locomotive, the wrench is put on so it is in the 9 o'clock position and rotated till it is vertical in the 12 o'clock position. The wrenches are left on overnight so it can be clear and obvious to crew members that the valves have been shut off. It also helped explain to this newcomer on his first run day why the overflow pipe was a constant stream of water at 5 am when he tried to fill the boiler (an embarrassing and funny memory!). When opening the valves in the morning or after servicing, the wrench is put on the valve in the 6 o'clock position, hanging down, and rotated to the 9 o'clock position where it is horizontal.

I would definitely agree that the valves need a serious re-think for their future operational life!

The video is a quick bit I made during the first hydro test we gave the locomotive. Besides the usual small leaks from re-fitting pieces here and there (along with the need for new gaskets under the safety valves), you can see the leaking check valves. The engineer side leaked the worst and had to be completely shut off till what you can see in the video. Ive been told that with the asbestos packing, the valve usually lasted 10-15 years instead of the 2-3 years we have been getting out of the graphite yarn.
https://www.youtube.com/watch?v=O2dqb4j ... e=youtu.be

Stuck check valves usually are due to foreign material getting stuck in the valve, scale or grit that has made it past the tank strainer and blown through the injector.

On American locomotives I have seen many types of check valves right off the boiler. Traditionally a drop or lift check valve was used right off the boiler or was integrated into the stop valve body. On many shortline and logging locomotives on the West Coast, the shops would simply add a second or sometimes third check valve in the injector line...I guess if one is good more is better?

Current days I have seen lift, swing, and ball checks used on injector lines. Most of these valves have bronze or stainless valve seats.

Johnathon

There's also the matter of wear in the surfaces in the valve body and in the poppet that align the poppet to the seat. They can start to cock and bind if they get too loose or nonparallel.

dave