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Shut off valves on steam cleaners


#1

I took the time yesterday to change the site tube on my steamer. I
also took the shut off valves apart to see if I could prevent them
from leaking around the valve stem. Doing this was a time consuming
chore that I imagine will need to be done again in the future. I
don’t understand the need for these shut off valves. When
maintaining the site tube a steamer can easily be drained. If the
site tube were to break under pressure, it would not be a smart idea
to try to shut these valves until all of the steam had been released.
I suppose the valves could be shut off in order to operate the
machine without a site tube until the place could be replaced however
a spare site tube is mandatory equipment in my shop.

I guess I have two questions. One, why the need for the shut off
valves at the site tube? Two is there any reason why the valve could
not simply be capped in order to prevent future maintenance issues?

John Sholl
J F Sholl Fine Jewelry
Littleton, CO


#2

Steamers are great tools, especially for spotless jewelry cleaning.
My experience with steamers over the years has been the traditional
boiler types, with the glass sight tubes, eventual leaking, boiler
failures, etc. There is a wonderfully convoluted procedure for
filling the boiler which is fairly complicated, involving releasing
air from the boiler as water is added to the boiler, opening and
closing valves, etc. Not good to overfill or underfill the boiler,
and there is time needed to get the apparatus "up to steam"
pressure.

I wanted one for my new studio, and a few years ago, through a local
supplier, I came across a used Steam Dragon steamer.

It was almost new, and priced at only $400, really cheap for a
steamer. I was unsure whether I would like its “boilerless” design,
but have found it to be a great steamer, with few of the problems of
a traditional “boiler” type steamer. These Steam Dragon units don’t
have a pressurized boiler, but a super heated chamber that water is
injected into, as needed, to create a blast of steam. A plastic tube
is inserted into a jug of distilled water, and when the foot pedal
is depressed, water is pumped into the heated chamber. Out comes a
strong blast of steam from the nozzle, which I have directed into my
shop sink. It’s a really simple machine, produces a powerful blast,
and seems less problematic than boiler type steamers.

Jay Whaley
www.whaleyworkshops.com


#3

Hi John,

The water gauge valves are required for agency approvals like ASME.
The purpose is to shut the valves in the event of a breakage or
leakage at the glass tube. On a small steam cleaner for jewelry use
it does not make much sense. Leakage is usually stopped by additional
tightening of the valve stem packing nuts. Teflon tape on the packing
nut threads does not work as the seal is accomplished by compressing
the packing around the valve shaft, not at the nut threads (we see
that a lot on steamers that come in for repair). We replace the valve
set if they leak after tightening the valve nuts. (if they leak after
tightening, they are in poor, unsafe condition, and the lower one
usually is packed with rust sediment.)

There is no practical way to remove the valve stems and cap the
valves, …and removing the entire valve set and glass tube, capping
the tank pipe fittings, would take away your ability to see the
water level. Considering the value of your time and safety, consider
replacing the valve set. You can buy them from the steamer
manufacturer, or MSC. (MSC number 56506959 for Reimers, Vigor,
Hoffman, Steamaster, or… MSC number 56506892 for the slightly
smaller valves like on the Grobet 24.850). Hope this helps.

John, The Jewelry Equipment Dr.


#4
I guess I have two questions. One, why the need for the shut off
valves at the site tube? 

Last I heard, it was in order to pass regulatory requirements for
"boilers", I think in New York (state or city, I don’t know). What I
was lead to believe is that the regulations applied across the board
to all steam generating boilers, regardless of size. A safety shutoff
makes great sense if that sight tube is in the large boiler of a
heating plant. Kind of useless for a steam cleaner, but if you’re a
manufacturer who wants to sell your unit to areas that require those
codes to be met, you put in the valves. This all comes from years ago
when I got a small all stainless steamer from Frei and Borel (now
Otto Frei). Forget the brand. It was all stainless, including the
boiler tank, with a heating element that wrapped around the tank,
instead of being in it. That made it immune to heating coil burnout
if the tank ran dry, and being stainless, it wouldn’t corrode. All in
all, nice design. It’s sight tube had no valves, though, so you
couldn’t buy it in New York… At least that’s what I was told.

Peter Rowe