6
$\begingroup$

A friend of mine that doesn't use the internet much runs a commercial laundry. They use an old 'Manlove Tullis' laundry calendar (c. 1980) that looks like this:

(click to enlarge photos)

Essentially, it is a machine with 3 rollers (2 visible in the photo) on a hot plate. Garments (e.g. bedsheets) go in wet, and come out ironed flat, and dry.

The hot bed runs on steam fed by 6 pipes (2 for each roller) underneath the machine, coming from a big boiler.

A couple of days ago 1 of the pipes broke off/burst under the machine with wear & tear over the years; where the pipe is joined by a coupling to the hot bed.

It is possible that over the years with repeated super-heating and cooling some metal fatigue has crept in, or it became so brittle that it finally failed.

After allowing the machine and the pipes to cool down for a day, he went under the machine to try to fix it; but the pipe is seized to the [possibly brass] coupling. The coupling affixes to the hot bed and it appears it cannot be removed because it is both seized and in an inaccessible part of the machine. It is a 22mm coupling.

The pipe is steel, and could be cut off and a new one joined by welding it or something.

Underneath the machine, the working area is only 50cm in height at most, and it is 10ft x 15ft / 3m x 5m.

From how it's been explained to me, when you're under the machine lying on the floor; the actual pipe/coupling that needs removing is within a small cavity above you. Something like this:

The space is very limited and the angle very awkward; there are also some health & safety issues with operating a welding torch under there.

An additional coupling could be added, but this introduces another mode of failure.

He has just installed a copper stop end, temporarily, so that he can use the machine with 2 out of 3 rollers operating at 100% and 1 operating at 50%.

The boiler operates at 8 Bar / 115 PSI — therefore the laundry calendar also operates at 115 PSI. From reading online I understand that the pipework is more than adequate. It is also regularly inspected and serviced.


My question is:

How can we get this pipe and/or coupling off and a new one on?


The person I'm posting this question for is very knowledgeable on the subject, but for the first time I've seen, he's stuck here. Three engineers have been out on-site and don't know what to do.

One has said that "it either needs to be welded or a proper coupling added; but it cannot be cut off because it is inaccessible".

$\endgroup$
5
  • $\begingroup$ System threw my half funny comment away. Brief summary: Cool selectively with copious CO2 from extnguisher than apply what force you can. | Same but heat selectively 1st. | Same maybe with best penetrating fluid - freezing this may not help. | Wicking in somethingh that can then be freeze expanded MAY help. | $\endgroup$ – Russell McMahon May 4 '15 at 6:43
  • $\begingroup$ Thank you for your suggestions @RussellMcMahon, they're much appreciated! I've just told him what you said, and he said he's tried with the penetrating fluid, but it didn't help. Going to try your other ideas tomorrow - cheers! $\endgroup$ – Danny Beckett May 4 '15 at 16:50
  • $\begingroup$ Do you have to have a welded connection to meet code, or would threaded suffice? There are handheld power threaders for tight spaces. What about the other end of the pipe, is it any more accessible, such that you could replace the entire length? $\endgroup$ – Air May 11 '15 at 16:45
  • $\begingroup$ @Air It is currently threaded, so threaded would definitely suffice. Thanks for letting me know about there being handheld power threaders; the issue is also in removing the coupling. There's no space to cut. I've edited the question to clarify slightly. $\endgroup$ – Danny Beckett May 15 '15 at 21:46
  • 1
    $\begingroup$ Was there any update on this? $\endgroup$ – hazzey Jan 30 '16 at 21:25
4
+100
$\begingroup$

The way of removing couplings in the worst case scenario, where all other alternatives has failed, is to physically destroy the coupling.

Cut/grind 2 slots the entire length of the coupling on opposite sides, usually one on top and one on the bottom. The slots need to be deep enough that it is at least flush with the pipe its screwed onto, pretty much as close to the threads as possible. The closer it is to the threads the easier this will be.

Fill the top slot with anti-seize or some good EP lubricant. Get a sharp steel wedge (also covered with anti-seize) and hammer it into the slot, work slowly from one end of the slot.

If the coupling is cast iron it will likely crack right off. If its mild steel or some other soft material it will slowly open up, and you can probably unscrew it after it loosens up only a bit.

For the steel wedge, grinding down a cold chisel can work too, just taper the chisel a bit more to make it easier to hammer into the cut groove.

The anti seize prevents the steel wedge from galling against the coupling.

The cut opposite the split cut is to give the coupling a place to bend.

$\endgroup$
4
  • 1
    $\begingroup$ Seems like if you have space to grind a coupling and hammer a wedge then you might as well just cut the coupling off and cut new threads into the pipe (if code allows). Who knows what condition the old threads are in, even if you manage not to damage them during the removal. $\endgroup$ – Air May 11 '15 at 16:41
  • 2
    $\begingroup$ Most of the time when it is impossible to fit a saw perpendicular to the pipe, you can still squeeze in a reciprocating saw (or in some worse case scenario, hacksaw blade attached to tip of a pole) lengthwise to slot the coupling. And for minimal clearance splitting/hammering, using something like slide hammer log splitters. $\endgroup$ – Netduke May 13 '15 at 15:47
  • $\begingroup$ Sure, but the problem statement specifies that cutting the pipe is an option, and power threaders can be pretty compact. I'm not saying this is a bad method, just not sure it's the most useful in this particular scenario. $\endgroup$ – Air May 13 '15 at 19:06
  • $\begingroup$ Thanks for your detailed answer. Unfortunately the problem comes in that there is no space to cut the old coupling off. I've edited the question to try to make it clearer. The bounty is about to expire, so I'll award it to you, but I'm still looking for the answer. Thanks!! $\endgroup$ – Danny Beckett May 15 '15 at 21:48
1
$\begingroup$

This doesn't answer the "how can we get the coupling off" question, but explores the welding option further. It seems that welding looks like one of the main options if the coupling is seized in place.

Due to the space restrictions it might be worth looking into hiring a portable orbital welding unit. This assumes that there is a pipe stub coming out of the seized coupling that could be prepared and welded to. The orbital welders are able to be used in tight spaces without much clearance behind; however, they do require careful setting of parameters.

Im not saying this is a definite solution, but it's worth looking into and possibly contacting welding unit manufacturers about parameters needed and whether it would be suitable for your application.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.