106 South Elm Street, Newkirk, Oklahoma 74647
A very interesting and informative article appeared recently in
The Iron Men Album by Mr. H. S. Fox, in which he gives an excellent
description of the injector and explains the technical principles
of its operation.
In this little piece I will try to tell something of the
troubles that can be encountered in the use of these handy and
useful devices. The advice I will try to give is not for the old
timers who used to make their living running steam engines, as most
of them perhaps know more about injectors than I do; but
unfortunately not many of these men are around any more, and maybe
I can help some of the younger people who are restoring old engines
and building models.
My experience began in the year 1906 when I was 12 years old
firing an old Garr-Scott traction engine in a sawmill operated by
my father and my uncle; and when I retired a few years ago, I owned
a sawmill that was driven by a Skinner steam engine with
cylinder-dia. 14′, stroke 15′. The boiler was 5′
diameter, 23′ long, and carried 200 lbs. pressure. Water was
supplied to the boiler by a steam pump that worked through an
exhaust heater. However, I strongly advise against pumping cold
water into a boiler. It will cause leaking flues and sometimes
worse damage, so I always had a couple of injectors to use when the
engine was shut down with no steam in the heater.
During the years from 1906 to 1966,I had to do with a good many
injectors, and maybe some of the younger folks will be helped in
getting these very useful but sometimes ornery devices to
behave.
Now back to the old Gaar-Scott. It was equipped with a Hancock
Inspector. A Penberthy was in the junk box that the former owner
said was worn out, but few people knew anything about repairing
injectors in those days, so it probably needed a new delivery jet
that could have been bought for about $1.75. The Hancock Inspirator
was never furnished as original equipment on a traction engine. The
Hancock is a ‘Double Tube,’ sometimes called ‘Positive
Type,’ and while they possess some advantages over the
‘Automatic single tube’ such as the Penberthy, U. S. and
others for stationary boilers, they are not suitable for traction
engines. The reason is that with a double tube injector the
overflow valve is closed by hand when it is working to the boiler,
and in case a traction engine moving on a rough road gives it a
severe jolt or if the intake hose or supply pipe in the tank is
momentarily exposed, the inspirator will ‘kick off,’ and
since the overflow valve cannot open, steam will be blowing into
the tank. So if the operator does not notice it immediately, he
will have a tank full of hot water and low water in the boiler.
With the Penberthy, U. S. or other good automatics, if the water
intake is exposed or the engine gets a severe jolt, the overflow
will open for a few seconds and then restart to work automatically.
For this reason the ‘automatics’ such as the Penberthy and
U. S. were developed. When I was firing the old Gaar-Scott, we were
not moving on the road so the old inspirator didn’t get any
jolts, but the steam supply pipe was tapped into the main steam
line to the engine. A hard pull in a big log would often cause it
to kick off. Taking steam from the main steam line is not a good
practice. Any injector will perform better if it has its own steam
line.
Now I will try to give some advice about how an injector should
be connected. In restoring an old engine the original plan should
be followed if possible. Most people like to see an authentic
restoration, and the engine builders generally had a pretty good
idea of how to do the job. The injector should be placed in easy
reach of the operator. All piping should be direct and short as
possible and should be the same size as the connections. The only
exception to this is that the steam supply pipe can be one pipe
size smaller if it is short and direct. The steam should be taken
from the steam dome at as high a point as practical and should not
be connected to any pipe leading elsewhere. If two injectors are
used they should be completely independent of each other. A
shut-off valve must be placed close to the dome at the highest
point in the line so it can be shut and the piping drained in cold
weather. This should be an angle valve screwed on a nipple about
two inches long that is tapped into the dome. (As stated before,
most people prefer an authentic restoration, I would also, but this
plan of piping was generally followed.) The valve stem should
extend outward. This will make it possible to renew the packing if
necessary with steam up and also will be more convenient. The pipe
should extend downward several inches to a little above the top of
the boiler and back in a horizontal direction to where the injector
will be in easy reach of the operator. A valve must be located here
to turn the injector on and off. This is usually an angle valve
screwed directly on the injector. This horizontal pipe should have
a drain to keep it from freezing in cold weather if the engine
should be in a position that it would not drain through the
injector. Most injectors have a drain in the bottom, but if there
is none, the piping must be arranged so it will drain. There must
be a shut-off valve close to the boiler where the feed water
enters. A gate valve is preferable but angle or globe valves are
often used. The check valve should be only two or three inches from
the shut-off and there must be a drain between so that water will
not be trapped between them. In general, plenty of care must be
taken to prevent freezing. Burst pipes are bad but frozen valves or
injectors are disastrous. The feed water should enter the boiler
forward near the smoke stack where the heat is not so great, and at
a point on the side a little below half down the side in the
vertical direction. Some real old engines had the feed water
entering the boiler at the bottom of the fire box, but all modern
boilers of the fire box, sometimes called ‘locomotive’ type
put the water in well up forward on the side.
There must be a regulating valve in the suction line close to
the injector. It should be closed when not in use to prevent the
suction pipe or hose from becoming heated should the steam valve or
the check valve leak. An injector will not work through a hot
suction line and it will not do much good to pour water on the
injector unless the line is cooled also, but more about hot water
later.
All the pipe fitting must be done carefully so that the unions
will fit perfectly. There must be no leaks, this applies especially
to the suction side. No injector will work if air is getting into
the suction pipe or hose. The overflow valve must not leak. There
is suction on the outside of this valve when water is going into
the boiler, and if air leaks in the vacuum in the combining chamber
it will be weakened, and the injector will work poorly or not at
all. All the parts inside must fit perfectly. If the machine is new
or in new condition, the joints will be good, but if it is an old
one there can be inside leaks. Mr. Fox in his article shows good
inside views of places where leaks might be found.
Now assuming that the injector is in good condition and properly
connected, everyone knows that it will not work coal cinders or saw
dust. The suction pipe must be fitted with a good strainer. The
strainer may become clogged if the tank gets full of trash or
chaff, so it is a good idea to have a coarse screen over the
opening where water is put in the tank.
If an injector that has been working well suddenly becomes
balky, it will often be found that in spite of a good strainer,
small pieces of stone have lodged in some of the small openings in
the jets; or sometimes scale or rust from the steam line may lodge
in the steam jet. If composition discs are used on the valves in
the steam line they may break, and small pieces lodge in the steam
jet. If no obstruction can be found, the trouble may be that an air
leak has developed in the suction pipe or hose. If an old hose is
used, the lining may have come loose and shut off the opening. The
packing on the stem of the water regulating valve is a frequent
offender, but where ever it comes from, the injector won’t
stand much air.
If trouble develops slowly, it is likely due to lime formation
in the inside tubes and jets, and check valve. The best way to
remedy this condition is to remove the injector, and soak it
overnight in a solution of ten parts water to one part muriatic
acid. Often it may not be necessary to soak the whole machine.
Sometimes the delivery jet (this is the long tube that reaches’
to the bottom) may be removed and soaked in the solution. Never try
to clean the jets by running tools of any kind through them. Damage
is sure to be the result.
The jets or tubes inside will wear out finally from use, and if
the water contains sand they may wear out fast. Back in the old
days when thousands of injectors were being sold every year it was
easy to get replacements, but now I’m not sure that anybody is
manufacturing them. Penberthy was still making several sizes of
injectors, but not a full line, and they may have quit altogether.
Be careful with your injector, or you may be hunting a fine
machinist to make a new tube. Quite often when an injector gets to
be balky the trouble will be found in the check valve. Lime
formation can cause plenty of trouble and sometimes is more trouble
to remove than it is from the injector. A leaky check valve is bad.
If it leaks it should be re-ground or fitted with a new disc if it
is the kind that has renewable discs.
Now I wish to discuss a very important characteristic of the
injector. No injector will work HOT WATER. Some will work hotter
water than others, but when the water gets above 110 degrees, the
ordinary automatic injector will give trouble. The reason for this
is that the water must be cool enough to condense all the steam
before the mixture of water and steam reaches the smallest part of
the opening through the delivery jet. When steam is condensed, the
water that is formed only occupies about one 1/000 th. as much
space as the steam from which it came. This makes a vacuum and
increases the velocity of the stream of water so that it can
overcome the pressure and enter the boiler.
If compressed air is blown through an injector it will create
suction that will pick up water and discharge it through the
overflow with considerable force, but not near enough to make it
enter the tank from which it came.
As stated before, some injectors will work hotter water than
others. An old catalogue that I have says that a Hancock Inspirator
will work water at 150 degrees if it flows to the suction chamber.
They don’t mean under pressure. They mean with just enough
force to fill the suction chamber. I have never seen this
demonstrated, but I doubt that Hancock Inspirator makers would make
any false claims.
During the ‘heyday’ of the steam era about 1905, large
steam plowing engines, in fact all steam traction engines were
introduced that carried higher pressure. Also the big plowing
engines used steam jet pumps to carry the water from the wagon
tanks to the engine tank. The jet pumps warmed the water, so, a
need arose for injectors that could handle high pressure steam and
warm water. To meet this need, Penberthy and others bought out
special models to meet the demand for injectors to work at
pressures up to 200 lbs. They were marked SPECIAL and the
Penberthys were fitted with a drain cock in the bottom. The J. I.
Case engines that came out in 1911 and later were equipped with the
BB-330 SPECIAL in the smaller and medium size and with the CC-332
SPECIAL in the larger sizes. Before the SPECIAL Penberthy was
introduced, the makers of the U.S. Injector claimed that it would
work hotter water than any other. This might have been true, and
perhaps was part of the reason that the Penberthy Company brought
out the SPECIAL.
During this era when steam was in almost universal use,
manufacturing injectors was big business. An old catalogue that I
have lists 16 sizes each of automatics. There were also several
other makes. Traction engines were all equipped with the automatic
type, and many of the portable and small stationary steam plants
used them, but most of these preferred the double tube type. The
chief advantage that the double tube possesses is that it will work
through a much greater pressure range. The Hancock Inspirator can
be started at 15 lbs. pressure and will work to 250 lbs. without
adjustment. They will also continue to work as the pressure goes
down. There were several makes of double tubes. The LEADER was
widely used. The Garfield was also well known.
Large stationary steam power plants didn’t have much need
for injectors. They nearly always used condensing engines. This
means they condensed the exhaust steam instead of turning it into
the air or the smoke stack. It went into a chamber where it came
into contact with tubes carrying cold water. This condenses it and
as the water that is formed only occupies a small fraction of the
space the steam did, a vacuum is formed. This causes what you might
call a suction on the piston which adds a lot to the power
obtained. This water that is formed is only allowed to cool
slightly below the boiling point before being pumped back into the
boiler. An injector with its dislike for hot water is useless.
Now probably the biggest injector business. The steam locomotive
was riding high on the rails and every one of them had two one on
each side. They were almost always of the double tube type. The
motion of a locomotive on the rails was not violent enough to
interfere with the operation. The NATHAN was one well known make
and the OHIO was another.
After World War I, the use of steam traction engines and all
small steam power declined so abruptly that the injector business
almost disappeared. Penberthy cut their line from 16 sizes to 9.
Most of the others quit altogether.
Now I have something to tell. Since I started writing this
article a couple of months back, I thought that it might be a good
idea to order an extra delivery jet for the BB-330 SPECIAL that we
have on our old Case engine. Well it came and the bill!!!!
WHOOEE!!!! $70.47!! This delivery jet, a little over 2′ long
cost about $2.00 in 1916 when the engine was built!
Another thing about our old CASE. We have it completely
authentic from the draw bar to the spark arrester, except that on
the right hand side in the place where the earlier Case engines had
their Penberthy, we have a Leader. We find that this injector is so
handy. It will work down to 15 lbs. steam pressure and this saves
quite a bit of fuel when filling up the boiler at the end of a day
at the engine show. The Leader operates on the same principles as
the Hancock but it is much handier as one lever controls the
operation.
The A.S.M.E. code, which is the law in most states, requires all
boilers containing as much as 300 square feet of heating surface,
to have two means of feeding water into the boiler that are
independent of each other. Common prudence should indicate the
same.
All in all, if you do not wish to be embarrassed by having your
injector take out on you just as you are getting in line for the
parade at the steam engine show, keep the pipes tight and the water
clean and cool.
