Reflex gauge

[Lopez Mike]

Fred,

I'm going to buy a couple of those unions and look them over carefully. Several of the local boats here have been using them for years with no problems.

The steel plumbing unions have been remarkably hard to come by. I've been getting blank looks from countermen at the supply houses. I'm using 'box store' Taiwan cast iron ones right now. Probably they will be O.K. but I try to fix anything that i find myself thinking about more than once.

Mike

[DetroiTug]

On the new Reflex install that started this discussion, we went with hydraulic nipples (Great name for a band . I went back and looked at McMaster-Carr and they indeed do not comply with ASTM A106, they do comply with ASTM - A108, whatever that is. I just ordered some Schedule 160 nipples that do comply. That will replace everything up to the new flange. The hydraulic components are supposed to be very strong, but they have no rating over 72 degrees. I will leave them on the top and bottom of the gauge. The way I intend to use this is open the gate valves just enough and a bit beyond for the gauge to work. As much the boat rocks around, I can see the water level fluctuating which tells me both ends are flowing freely. That is how I used the other tube glass, it was an antique without excess flow checks.

-Ron

[steamboatjack]

Folks,

I believe there are a few basic principles here that are getting missed, There are two potential problems, broken/leaking unit and blocked passages preventing a correct reading of the water level.
The cocks or valves on a gauge glass are used for isolation for repair of the unit, they are equally essential for “blowing the glass” an operation that should be carried out on a regular basis dependent on the boiler service. Merely a quick wizz on the drain is insufficient. There is a correct procedure laid down by the “board of trade” as it was known in the UK and I am sure is the same in the USA.
Historically (probably the same today) the BOT oral examination started with the examiner showing the candidate a picture of a gauge glass and asking him/her the method of blowing. Should this be wrong that was it, “you can go home now!”
Most gauge glasses of boat size use a quarter turn cock as stated above by others, the best current practice is the Klinger type sleeve packed cock, although a ball valve if of sufficient spec. can be used.
If you are going to make up your own gauge glass arrangement, then why not do it correctly?
Regards Jack

[Lopez Mike]

I agree with Jack that having a blowdown valve on the bottom of the gauge is prudent and, in fact, required for our annual boiler test here in my area (Puget Sound).

A small thing but small things (omitted) can lead to big things. "For want of a nail . . . "

Mike

[S. Weaver]

I believe there are a few basic principles here that are getting missed, There are two potential problems, broken/leaking unit and blocked passages preventing a correct reading of the water level.

The cocks or valves on a gauge glass are used for isolation for repair of the unit, they are equally essential for “blowing the glass” an operation that should be carried out on a regular basis dependent on the boiler service. Merely a quick wizz on the drain is insufficient. There is a correct procedure laid down by the “board of trade” as it was known in the UK and I am sure is the same in the USA.

Jack, it is.

Historically (probably the same today) the BOT oral examination started with the examiner showing the candidate a picture of a gauge glass and asking him/her the method of blowing. Should this be wrong that was it, “you can go home now!”

Exactly. Or as I witnessed, "The examination is over. You may schedule another when you are properly prepared."

Most gauge glasses of boat size use a quarter turn cock as stated above by others, the best current practice is the Klinger type sleeve packed cock, although a ball valve if of sufficient spec. can be used.

If you are going to make up your own gauge glass arrangement, then why not do it correctly?
Regards Jack

Thanks, Jack.

[fredrosse]

I have spent some time looking for "clean thru" type valves on gauge glass sets, and have found none in the USA market. Many suppliers offer gauge glass sets for boiler service, with round gauge glass and reflex type glass, however they all have a globe type isolation valves at the top and bottom of the gauge, and no way to "rod thru".

Gauge blowdown valves are either globe pattern or ball type, but they are not what we are talking about here. The approved ASME types evidently have to have the automatic isolation balls in case the glass breaks also.

So what am I missing here, are the USA and UK rules so different?

[S. Weaver]

Fred:

Without going into a contrast of the codes, "rodding through" of the USA reflex gauges is done on a periodic basis depending on the application by disconnecting the unions at the base of the valves. The whole contraption is easily removed this way. I am not sure about the tubular gauges since it has been decades since I was around them in LP service. The essential same purpose is achieved, though once again I can appreciate British purpose-built engineering ...

[Oilking]

Fred:
The flat glass gauge you show is equiped with offset stem valves that allow for a straight shot through the gauge by removing the plugs top and bottom(blowdown cock). Penberthy has offset stem valves for flat and tubular gauges with the automatic ball check that are listed as meeting ASME code. They are also available with union fittings off the back of the valve which would make for a clean connection. The flat glass valves are forged steel and rated at around 1400psi @ 600F.
I just wonder how many clam$ they want for them?

Dave

[fredrosse]

I understand the option to have the gauge glass passage offset to allow easy mechanical cleaning of the glass with the isolation valves shut.

However what I am asking about is the gauge isolation valves, evidently in the UK they have to be a cock or ball valve that allows mechanical cleaning, or "rodding out", but in the USA they are globe type valves, and no "rodding thru" is possible. This is the issue where I am surprised that the UK vs. US is evidently so different. The gauge valves with the ball checks built into them (in typical US practice, to stop flow if the gauge glass breaks), also prohibits passing anything thru.

[Oilking]

Fred,
The way they are able to rod through is that the ball check is in a chamber before the valve seat. With an offset stem there is then a clear passage. I have a set of Penberthy inline stem valves for a tubular glass, the lower valve has the ball check in the globe above the stem, and the upper valve, due to the laws of gravity, has the ball check located before the seat. In the offset stem they choose to place the ball check before the seat on both so there is a clear path through the glass. I'm new to this and couldn't figure out how to attach the image, but the bulletin page listed has a drawing.
http://valves.pentair.com/valves/images ... in-pen.pdf
page 24

Dave