It is very important when the pump fails to work to ascertain what the
trouble is. If it should stop suddenly, examine the tank and ascertain
if you have any water. If you have sufficient water, it may be that
there is air in the pump chamber, and the only way that it can get in is
through the stuffing box around the plunger, if the pipes are all tight.
Give this stuffing nut a turn, and if the pump starts off all right, you
have found the trouble, and it would be well to re-pack the pump the
first chance you get.
If the trouble is not in the stuffing box, go to the tank and see if
there is anything over the screen or strainer at the end of the hose.
If there is not, take hold of the hose and you can tell if there is any
suction. Then ascertain if the water flows in and then out of the hose
again. You can tell this by holding your hand loosely over the end of
the hose. If you find that it draws the water in and then forces it out
again, the trouble is with the first check valve. There is something
under it which prevents its shutting down. If, however, you find that
there is no suction at the end of hose examine the second check. If
there should be something under it, it would prevent the pump working,
because the pump forces the water through it; and, as the plunger starts
back, if the check fails to hold, the water flows back and fills the
pump barrel again and there would be no suction.
The trouble may, however, be in the hot water check, and it can always
be told whether it is in the second check or hot water check by opening
the little drain cock. If the water which goes out through it is cold,
the trouble is in the second check; but, if hot water and steam are
blown out through this little drain cock, the trouble is in the hot
water check, or the one next to the boiler. This check must never be
tampered with without first turning the stop cock between this check and
the boiler. The valve can then be taken out and the obstruction
removed. Be very careful never to take out the hot water check without
closing the stop cock, for if you do you will get badly scalded; and
never start the pump without opening this valve, for if you do, it will
burst the pump.
The obstruction under the valves is sometimes hard to find. A young man
in southern Iowa got badly fooled by a little pebble about the size of a
pea, which got into the pipe, and when he started his pump the pebble
would be forced up under the check and let the water back. When he took
the check out the pebble was not there, for it had dropped back into the
pipe. You will see that it is necessary to make a careful examinations
and not get mad, pick up a wrench and whack away at the check valve,
bruising it so that it will not work. Remember that it would work if it
could, and make up your mind to find out why, it don't work. A few years
ago I was called several miles to see an engine on which the pump would
not work. The engine had been idle for two days and the engineer had
been trying all that time to make the pump work. I took the cap off of
the horizontal check, just forward of the pump barrel, and took the
valve out and discovered that the check was reversed. I told the
engineer that if he would put the check in so that the water could get
through, he would have no more trouble. This fellow had lost his head.
He was completely rattled. He insisted that "the valve had always been
on that way," although the engine had been run two years.
Now the facts in this case were as follows: The old check valve in place
of the one referred to had been one known as a stem valve, or floating
valve. This stem by some means, had broken off but it did not prevent
the valve from working. The stem, however, worked forward till it
reached the hot water check, and lodged under the valve, which prevented
this check from working and his pump refused to work, the engineer soon
found where the stem had broken off, and instead of looking for the
stem, sent to town for a new check, after putting this on the pump now
refused to work for two reasons. One was, he had not removed the broken
stem from the hot water check, and another was, that the new check was
in wrong end to. After wasting another hour or two he finally found
and-removed the stem from the hot water check, but his pump still
refused to work. And then as the boys say, "he laid down," and when I
called his attention to the new valve being in wrong, he was so
completely rattled that he made use of the above expression.
There are other causes that would prevent the pump working besides lack
of packing and obstructions under the valves. The valve may stick.
When it is raised to allow the water to flow through, it may stick in
the valve chamber and refuse to settle back in the seat. This may be
caused by a little rough place in the chamber, or a little projection on
the valve, and can generally be remedied by tapping the under side of
check with a wrench or hammer. Do not strike it so hard as to bruise
the check, but simply tap it. If this don't remedy the trouble, take
the valve out, bore a hole in a board about I/2 inch deep and large
enough to permit the valve to be turned. Drop a little emery dust in
this hole. If you haven't any emery dust, scrape some grit from a
common whetstone. If you have no whetstone, put some fine sand or
gritty soil in the hole, put the valve on top of it, put your brace on
the valve and turn it vigorously for a few minutes, and you will remove
all roughness.
Constant use may sometimes make a burr on the valve which will cause it
to stick. Put it through the above course and it will be as good as
new. If this little process was generally known, a great deal of
trouble and annoyance could be avoided.
It will not be necessary to describe other styles of pumps. If you know
how to run the cross head pump, you can run any of the others. Some
engines have cross head pump only. Others have an independent pump.
Others have an injector, or inspirator, and some have both cross head
pump and injector. I think a farm engine should be supplied with both.
It is neither wise nor necessary to go into a detailed description of an
injector. The young reader will be likely to become convinced if an
injector works for five minutes, it will continue to work, if the
conditions remain the same. If the water in the tank does not become
heated, and no foreign substance is permitted to enter the injector,
there is nothing to prevent its working properly as long as the
conditions are within the range of a good injector. It is a fact that
with all injectors as the vertical distance the injector lifts is
increased, it requires a greater steam pressure to start the injector,
and the highest steam pressure at which the injector will work is
greatly decreased. If the feed water is heated, a greater steam
pressure is required to start the injector and it will not work with as
high steam pressure. The capacity of an injector is always decreased as
the lift is increased, or the feed water heated. To obtain the most
economical results the proper sized injector must be used. When the
exact quantity of water consumed per hour is known it can be easily
determined from the capacities given in the price lists which sized
injector must be selected.
An injector must always be selected having a maximum capacity in excess
of the water consumed. If the exact amount of water consumed per hour
is not known, and cannot be easily determined, the proper size can be
approximately determined from the nominal H. P. of the boiler. The
usual custom has been to allow 7 I/2 gallons of water per hour, which is
a safe rule for the ordinary type of boiler.