Operating pressure

[Mfoxchicago]

I too am having problems with my Penberthy AA-328 Injector that has developed, over the past two months, a persistent issue with sputtering, spitting and only wanting to send flow out the overflow port in to my hotwell. It is only locking in to siphoning correctly about 20% of the time.

This was not the case prior to me thinking that I needed to remove the drain/cleaning plug in the bottom "O" plug fitting. The injector had performed reliably the four previous months, since acquiring my boat. However, the removing and replacing the drain plug uncovered a long hidden treading issue that I thought could be corrected by purchasing a new "O" plug fitting. When the new fitting finally arrived, installed, it did not fix the problem - I found that the new fitting had significant machining differences from that of my 30+ yr old original piece. Back to square one. With some inventive problem solving, I have reinstalled the original "O" plug fitting & its drain plug so they do not leak any more, but I can not get a reliable Penberthy (and I know just how reliable they should & can be).

The overflow check valve seems to be flapping ok, looks ok - not sure if I actually know what to look for. The downstream check valve on the outflow to the boiler seems ok as well. The only moving part that I know of IN the injector is the perforated spindle in the unit and it seems clean and serviceable. This Penberthy has been on this vessel for over 30 years and I suspect has always operated as expected - now this. I am at a loss.

Any additional ideas. Your help is greatly appreciated!

[Lopez Mike]

We haven't heard from Wendell in quite a while. I wonder if he got his problem fixed?

I am no expert on injectors but the few times I have had them fail on me have been either due to something in the injector, apparently not the problem in these two cases, or a restriction between the injector and the boiler.

Twice I have had failures due to sticky or fouled check valves at the boiler. One it was a tiny hunk of wire (go figure?) and the other time it was a buildup of mineral deposits on a non-condensing locomotive.

I've always suspected injectors of operating by magic anyway. One ancient text I read referred to the steam 'chasing' the water into the boiler. Quaint.

[Mfoxchicago]

Thanks Mike for staying up so late and offering your knowlegable and witty insight as always. "Like magic" - I know what you mean. A steam siphon is an interesting concept that most novists that ride on TULE don't really understand even when you explain it to them.

But I have enough problems coaxing my ol' Gardner-Denver Duplex Steam Pump to be reliable. I don't need issues with my Penberthy as well. Seems when one is working, the other wants to try my nerves and then visa versa - go figure. I am calling the Penberthy plant this week to speak with their senior engineer to see if he knows where to put the finger on the problem straight away.

But, if you hear of any other possible solutions - please do contact me.

Wishing you all the best Captain!!!

[DetroiTug]

Mack,

This is in West Texas, it's July and it's probably hotter than it is here in Michigan - I'm going to say the ambient and water temps are having something to do with this. Even if you're pulling from a hotwell, outside ambient temperature raises the temperature of everything with it. Injectors need a significant differential in temperature between the steam and feedwater to operate properly. The remedy is generally a cold wet rag wrapped around the injector. I'd seriously look at adding an engine driven pump if there isn't one, they are the most reliable.

-Ron

[Lopez Mike]

I'll second Ron's advice on both counts. I hadn't thought of temperature problems as I live in the N.W. and the water is fairly cold. I have had to cool some very small injectors on model locomotives but they were about the size of your thumb.

I didn't realize you had no engine driven pump. I cannot imagine living without mine. It just runs along doing its thing without attention or fuss. Of course I have a condensing power plant with a hot well float so it's self regulating.

[wsmcycle]

The best advice i got was that you have developed an air leak in the supply line. I had mine paralleled with the hand pump so i put a valve to block the hand pump. I still had to have 80Lbs in order to operate. You can supply nothing but water, no air!. My water here in the Arkansas river is probably as hot as yours. Mine works in the hot summer time. If your looking for a reason the thing stopped working, it is probably an air leak in the supply side.

[wsmcycle]

I cant think of anything better than being missed. Progress has been very slow on the steam boat this summer. The Arkansas river has been flooded for two months. With no other body of water of much length in the area, I have not been very enthusiastic. That is not to say there has been NO progress. I did get the second injector i had running but it took 80#s to lite-up.
The biggest thing i've done of late was to install a cable steering unit in the fantail. This was quite difficult because there Is a fiberglass tube which runs all the way up through the boat to the deck. There was a nice tiller on the top but i didn't want to mount the steering section on top (visible). I got the cable and steering unit from a junk ski boat. The steering wheel looks terrible but i will replace it once i get the bugs worked out. The temp of the river is 87 today and the flow is 65k cubic ft per sec. It was 230k a few weeks ago.

[Mfoxchicago]

Mack,

This is in West Texas, it's July and it's probably hotter than it is here in Michigan - I'm going to say the ambient and water temps are having something to do with this. Even if you're pulling from a hotwell, outside ambient temperature raises the temperature of everything with it. Injectors need a significant differential in temperature between the steam and feedwater to operate properly. The remedy is generally a cold wet rag wrapped around the injector. I'd seriously look at adding an engine driven pump if there isn't one, they are the most reliable.

-Ron

Thanks Ron, good suggestions. We've been consistently hitting air temps over 90 to 100 degrees for the past month here. I haven't checked the temp of the "cold water" feed coming out of my tanks, but suspect it will be the ambient temp of the lake, which is probably in the 70's or maybe higher....will look into that with this weekend's runs.

We do have a Gardner-Denver Duplex Steam Pump for feed water, when we need it. My crew has really got a hand on properly adjusting the Hot Well Feed/By-pass valves so the boiler pretty much feeds herself if you keep an eye on the water glass. I just really like the Penberthy Injector for adding tempered water at the end of the day to help calm the boiler down and putting her to bed. Plus, I just like having a redundant backup system for feed water in something like a steamboat.

[Mfoxchicago]

The best advice i got was that you have developed an air leak in the supply line. I had mine paralleled with the hand pump so i put a valve to block the hand pump. I still had to have 80Lbs in order to operate. You can supply nothing but water, no air!. My water here in the Arkansas river is probably as hot as yours. Mine works in the hot summer time. If your looking for a reason the thing stopped working, it is probably an air leak in the supply side.

Wes, how did you go about checking for air leaks in your feed water line to the Penberthy? That might be some of my problem.

[Steamboat Mike]

Three thoughts come to mind for dealing with a finicky Penberthy.

First, take the injector to the bench, remove the bottom cap as well as the steam cone and sight the bore to be as sure as you can that there is nothing stuck in it. I have found all manner of foreign and domestic refuse jammed into the small holes of an injector.

Second, if you have a globe valve on the supply line to the injector try the following: open the valve all the way till it stops turning, back off the packing nut a turn and place several drops of steam cylinder oil around the stem where it goes through the nut. Close the valve, add more oil should what you put there get absorbed as the stem goes down. The idea is to wet the packing with the heavy oil. This will make the valve turn easier and make a very good seal to the stem. It is surprising how much air can de drawn in through the packing that gives no indication of leaking under steam or water. Leaks will occur on vacuum that will not show under pressure, sometimes this trick can eliminate a vacuum leak that is very difficult to detect by any other means, anyway it can't hurt anything. Be sure your hose is not old and porous. Check fittings for proper make up. Be sure lines are clear.

Third, requires a little piping change. If you have a globe valve tee'd into the delivery line after the injector and before the boiler check and you open it before priming the injector you can sometimes trick the injector into starting and running dry. To do this prime the injector then open the steam wide. The overflow should stop and the entire delivery will pass thru the open valve on the delivery line. Once this flow is established, gradually close the globe valve. This process allows the injector to achieve the velocity necessary to force the water into the boiler with no load at full steam, picking up the load gradually. This trick is helpful for starting at lower pressures and higher water temperature. This idea is actually not my own, it is from the Penberthy instructions for the smaller sizes of injector. What appears to be a drain valve on the lower plug is in fact a starting valve.

I have always felt that an injector is like a puppy from the pound. You don't know what you are getting until you get it home and by then, of course, it is too late.

Happy boiler feeding, best regards, Steamboat Mike .
Lt