Page 70 - Boiler_Operators_Handbook,_Second_Edition

Boiler Plant Operations 55

mering and banging because you changed the pressure
in a system too fast. The important thing to remember
here is that it will do the same thing the next time so
change your operating mode to eliminate that action
thereafter.
Always open and close valves slooowly until such
time as you know you can get away with spinning them.
Even then, don’t spin valves. Someone else may see
you doing it and follow suit anytime they’re directed to
operate one. Once upon a time I was a cadet on my first
ship and spun a boiler non-return valve open just like
I observed the second assistant doing. The difference
was he had done it while there was less pressure in the
boiler. I did it when the boiler pressure was considerably
higher than the rest of the system, oops! (I know what it
sounds like when boiler water is lifted out of the boiler,
bangs around in the superheater, and then hits the first
stages of the turbine; …it isn’t a pleasant sound.)
Despite my yelling at them about the same thing
year in and year out, I still find steamfitters putting
Figure 2-1. Warm-up bypass valves
valves way up in the air where you need a ladder, and
want to make sure that term is clear. I remember an ap- sometimes to act like a monkey, to get at the darn valves
prentice that we called Tiny who happily trotted off to to operate them. A valve is installed in a piping system
follow my instructions to crack a ten-inch steam valve in so someone can shut it off when necessary and anything
the upper level of a boiler room. I was very grateful that higher than four feet off the floor is a pain to operate. I
he decided to get some clarification and leaned over the design systems with piping dropped to pressure reduc-
rail on an upper platform (with the twelve-pound maul ing stations, distribution headers, etc. to put valves at
he had in his hand showing) and yelled down “Mr. Ken, operating level only to find later that the contractor
exactly where do you want me to hit it?” convinced the owner (who doesn’t do the operating)
To crack a valve means to open it until the disc lifts that money could be saved by rearranging the piping a
off the seat (creating a small opening or crack for the little. How frequently do operators expose themselves
fluid to flow through). A ten inch steam header shut-off to potential harm by climbing up to get at a valve just so
valve should have something like a three inch globe someone could save a few bucks on an installation?
bypassing it to allow warm-up of the steam main. Try In other instances the contractor simply put the
as hard as you can and you still won’t be able to crack a valve where a pipe joint was needed. If you’re associ-
valve that large without producing a significant surge in ated with new construction do your best to get valves
steam flow. I encountered a valve that took two turns of located where they’re convenient. If they aren’t conve-
the wheel to close it back off after I cracked it open and nient and you have to operate them more than once a
the resulting jump in steam flow lifted the boiler water year then ask for an extension. A chainwheel or exten-
level in the boiler to the point it tripped on high level. sion rod is going to cost the owner something but all
Another common and dumb trick is filling a hot you have to do is mention the cost of the workmen’s
water boiler by opening the main shut-off valves so you compensation claim if you fall while trying to operate
drop the pressure in the whole system and steam starts that valve. Don’t let them get cheap either, ask for the
flashing off at all the high points then collapses as pres- chainwheels with the built in hammers that help drive
sure is restored. the valve open whenever it’s larger than three inch. Use
Regardless, you should always crack any valve oversized chainwheels otherwise. Push the issue, think
as the first stage of opening it. When the valve is larger of yourself and remind your employer, if you’re all
than two inch wait a moment or two to see what hap- alone in the boiler plant and fall while climbing to reach
pens while preparing to spin it shut again; if you have a valve it’s going to cost a lot more than installing an
to. Then you can wander off whistling and looking extension rod or chainwheel.
around, playing the innocent party, if systems start ham- I don’t understand why but I haven’t run into any