Part 6

This style of engine ranges in size from 35 to 350 horse-power approximately, the speed of the smaller ones ranging from 275 to 325 revolutions, and of the larger from 160 to 185 revolutions, and are used extensively where high speed is required, and where the load is of an intermittent character.

TESTING PISTON RINGS AND VALVES.

To ascertain whether the piston rings and valves are leaking or not, first place a block of wood about four inches long upon the guide for cross-head and against the front cylinder head. Then turn the engine “over” until the cross-head comes back tight against the block. This will place the valve of a simple engine in such a position that steam would be admitted to cylinder through front steam port. If a reversing engine, throw the reverse lever in the last notch in end of quadrant that would allow the engine to run “over”. Then take off the back cylinder head, and open the throttle valve wide. If steam blows out past the piston, it would indicate that the rings were not tight. In case steam packing rings are used, they should be refitted or replaced by new ones. If adjustable rings are used, they should be adjusted to stop the leak, care being taken not to get them too tight. If the steam blows out through the back port, the slide valve is not tight and it will require refitting, as will also the valve seat.

If a very small amount of steam blows through, new rings or adjustment would not be necessary, as the waste of steam or back pressure resulting from it would amount to very little.

This test should be tried occasionally with a full head of steam on, to assure of the piston rings and valve being tight, as leaky pistons and valves are very wasteful of steam, sometimes causing priming, and greatly diminishing the power of the engine. Never run your engine with leaky piston or valve. Have them properly fitted at once.

After making the test, and repairing if necessary, replace the cylinder head, and be sure to remove the wood block from the guides.

KNOCKS OR POUNDS.

The Knocks or Pounds of steam engines are frequently caused by lost motion in the crank and wrist-pin boxes, valve rod and valve, cross-head and link; looseness of the piston rod, pillow block or main bearings, follower plate, or eccentrics; the slide valve having not enough or too much lead, the exhaust being cut off too soon or too late, shoulders being worn in each end of the cylinder by the packing rings not traveling over the counter-bore at the end of each stroke; or shoulders may be worn in the guides by the cross-head slides, or they may not be adjusted properly to fit the guides; boiler may foam, causing the water to be drawn over in cylinder; the piston rings may leak, thus causing cushioning; and as the crank approaches the centers, steam occupies the space between the cylinder head and piston, causing a tremendous strain upon the engine; the piston rod being packed too tight, the boxes and pins being worn flat or oval; the key in driving pulley may be loose.

TO REMEDY KNOCKS OR POUNDS OF A STEAM ENGINE.

While it is hardly possible to prescribe a remedy for all cases, if the following practical methods are closely followed they will be found to be very useful, although in many instances the remedy must be determined by the circumstances of the individual case.

The knock or pound of boxes in connecting rod at cross-head or crank pin or the valve rod, may be remedied by taking out the boxes, and filing off the top and bottom inside edges sufficiently to allow them to just come together and not fit the pin too tightly. In replacing them, be careful not to key them up too tight.

Where there is not sufficient draught in the key or gib, place a liner in front or behind the boxes.

Knocks or pounds in the link may be remedied (if the link block has too much play in the link) by reducing the liners in each end of the link enough to fit the block properly.

The knocks or pounds of piston are caused by the rod becoming loose in the head; and if allowed to continue, will destroy the fit of the rod in the hole. It may be remedied under such circumstances by removing the rod, re-boring the hole and bushing it perfectly true, and refitting the rod.

Knocks or pounds of follower plate are generally caused by dirt accumulating in the hole, which will not allow the bolts to enter far enough to take up the lost motion of the plate, or the bolts may be too long. To remedy this, remove the accumulation of dirt from the hole, or shorten the bolts.

The knocks or pounds in main crank shaft, if caused by the bearings being worn oval or out of round, may be remedied by removing the shaft; true it up in a lathe, and refit or re-babbitt the boxes.

The knock or pound in eccentrics is generally caused by the eccentric straps being too loose upon the eccentrics, which can be remedied by reducing the liners in the straps to allow them to fit perfectly.

The knock or pound in slide valve caused by being improperly set, may be remedied by taking off the steam chest bonnet and re-adjusting the valve so as to give the same amount of lead at each end of stroke. This being done, and the valve well proportioned and the connections properly fitted, there should be no knocks or pounds from this cause.

The knock or pound in cylinder caused by shoulders being worn in it, can be remedied by re-boring the cylinder, being sure to make the counter bore of sufficient depth to allow the piston rings to overlap them at the end of each stroke.

The knock or pound on guides caused by shoulders being worn on them, is remedied by planing the guides and making the shoe slides of sufficient length to overlap the guides at either end when crank is on the center.

The knock or pound caused by the cross-head slides not fitting the guides properly, may be remedied by adjusting them both top and bottom to fit the guides closely, being careful not to get them too tight, which causes undue wear and strain upon the frame.

The knock or pound caused by wrist-pin or crank-pin becoming worn flat or oval, may be remedied by filing them perfectly round.

The knock or pound caused by the piston leaking, which causes cushioning, can be remedied only by having a tight piston.

The knock or pound caused by the driving pulley key being loose, can be remedied by driving the key in its seat; or if a defective key, replace by a new one perfectly fitted.

If the knocks or pounds are caused by lost motion in any of the revolving, reciprocating or vibrating parts of an engine, they may be detected and located by placing the finger upon the different parts while the engine is running very slowly or worked back and forth by hand.

HEATING OF JOURNALS.

The heating of journals and reciprocating parts of an engine may be attributed to the following causes:

Improper proportions and fitting, unsuitable material, want of homogeneity between the metals of which the journals and bearings are composed, the revolving or reciprocating parts not being in line, the boxes being keyed up too tight, sand or grit getting into the journals, improper lubricating, etc. The last mentioned cause is very complicated, as the conditions of weight of load, area of surface subject to pressure, velocity of movement, etc., must be taken into consideration.

To remedy the heating of journals which is caused by the revolving or reciprocating parts not being in line, the engine or shaft must be put in line.

When caused by the boxes or bearings being too tight, they must be loosened a very little at a time until bearings run cool. Apply plenty of good oil.

Clean the boxes and journals thoroughly, and see that the oil holes are not stopped up; also see that the oil-cups are clean, to assure of the oil getting to the bearings freely.

Oiling frequently, using a little oil at a time, gives the best results and is the most economical.

PACKING PISTON AND VALVE RODS.

When the piston or valve rod of an engine or pump needs re-packing, take off the stuffing box gland, remove all the old packing carefully, and replace with new.

If a patent packing is used, it should be cut in suitable lengths diagonally across the packing, making the angle of one end opposite from that of the other, so that when ends are brought together they will make a splice joint. The joint of each ring of this packing should be placed at opposite sides of the rod, and the stuffing box filled, the gland replaced and screwed up just tight enough to stop leakage. If hemp packing is used, take about the amount required and pick it to pieces, removing all sticks, lumps or hard substances. Then twist it into three compact cords, saturate well with oil or tallow, and braid the cords together tightly. Then wind this braid around the rod until stuffing box is full, replace the stuffing box gland, and screw up as before described.

Care should be taken not to screw the packing in stuffing boxes too tight, as it not only increases the friction on the rod and diminishes the power of the engine, but will have a tendency to flute the rod. If the rod is once fluted, it will be very difficult to stop leakage at this joint.

When stuffing box of water piston of pumps needs re-packing, the same rule will apply, with the exception that little or no grease or tallow should be used upon the packing.

Always keep piston and valve rod packing in a clean place, as any dirt or gritty substance that may become attached to it will have a tendency to cut the rod.

SETTING A PLAIN SLIDE VALVE.

First, take up all “lost motion” and place the engine on the center. This is done by putting the wrist-pin, crank-pin and center of the main shaft in line. To do this accurately, turn the engine until the cross-head is about half an inch from the end of its stroke, and mark the position of the cross-head on the guide.

Place a marker against the edge of the fly-wheel, and make a mark on the fly-wheel opposite the marker, then turn the engine until the cross-head completes the stroke and comes back to the mark made on the guide.

The crank will now be as much below the center as it was above before. In this position make another mark upon the fly-wheel opposite the marker.

Now, midway between the two marks on the fly-wheel, when turned opposite the marker will put the engine on dead center. Next, remove steam chest cover and place the eccentrics about one-quarter turn ahead of the crank in the direction the engine is to run. If the engine is to run “over”, place the throw of eccentric up. If it is to run “under”, place throw of eccentric down.

Then set eccentric carefully at such a point that the valve will have just commenced to open say ¹/₃₂ of an inch on the end that should be taking steam. If there is a rocker arm used which reverses the direction of the motion, i. e., making the valve stem move in the opposite direction from the eccentric rod, the eccentric must be set behind the crank, when the engine is to run “over”, in order that the port may open as the engine turns forward; but if a rocker arm is used merely to multiply the motion without changing the direction, proceed as though there was no rocker arm at all. Next, measure the “lead” which you have given to the valve at end which you have set. This is easily done by pushing a wedge-shaped stick or piece of soft wood into the port opening. The edge of the valve and port will mark the distance it goes in. Turn the engine upon the other center, which will be found as before described, and see if the lead is the same at both ends of the valve. If it is, the engine is properly set. If it is not, move the valve on the stem towards the end having the greatest amount of lead, a distance equal to one-half the difference in the leads. If the equalized lead is more than is necessary, set the eccentric back a little.

There are numerous methods of attaching the stem to the valve. A common way is with jam-nuts. With this arrangement it is only necessary to turn back the nuts on end towards which the valve is to be moved, an amount which will allow the given movement; then, turn the other nuts until the valve is forced into place to travel equal distance both ways from its center position. When the stem screws directly into the valve, the connection to the rocker arm or guide must be taken apart, and the stem screwed into or out of the valve enough to give it the required position. After the valve is set, replace the steam chest cover, and secure the eccentric perfectly tight with the set-screws, to prevent it from slipping.

SETTING SLIDE VALVE OF REVERSING ENGINES.

The Link Reverse Being Used.

First, see that all the lost motion in the connecting rod, pillow block bearings and cross-head is taken up; then throw the reverse lever in last notch in quadrant, which would allow the engine to run “over”; then, remove the steam chest cover. Next, loosen eccentric (the eccentric rod of which is in direct line with the valve rod), turn the eccentric completely around, and watch the valve to see whether it laps the steam ports exactly the same amount at both ends, or travels an equal distance from its central position both ways. If it does, the valve is in proper position upon the rod. If it does not travel equally, the valve must be made to do so by adjusting it upon the valve rod, which is done by lengthening or shortening the rod, by use of jam-nuts, with which the rod is usually furnished. After this is done accurately, place the engine upon its forward center. This is done by turning the engine forward until the cross-head is about ½ inch from end of its stroke and mark the position of the cross-head upon the guide; then, with the use of long tram or dividers, mark from any convenient point on the frame to the band wheel or disc, and mark both points with prick-punch. Again turn the engine forward until the cross-head completes its stroke and comes back to the mark made on the guide; then, with the same long tram or dividers, mark the band wheel or disc as before from the prick mark already made on the frame.

Midway between punch marks on band wheel or disc, which can be found by use of dividers, will give the point which will place the engine on the “center” by turning engine back far enough to allow the long tram or divider to fit in punch mark on frame, and center punch mark on band wheel or disc. Now turn the eccentric over in the direction in which the engine is to run, until the valve gives the proper amount of lead on the front of steam port, which is about ¹/₃₂ of an inch, and fasten eccentric with set-screw. Then turn engine over the way it is to run, and place it upon its back center. This is done exactly as before described for forward center, and if the valve is properly proportioned, it will give the required ¹/₃₂ of an inch lead on the back steam port, and valve will be properly set for running in this direction.

Now throw the reverse lever in the last notch in opposite end of quadrant, which would allow the engine to run “under”, then loosen the other eccentric (the eccentric rod of which is in a direct line with the valve rod), and proceed same as described when engine is running “over”, to get valve to lap both steam ports equally. Then place engine upon either center and move the eccentric in opposite direction from the other eccentric until the valve gives the ¹/₃₂ of an inch lead to steam port, fasten the eccentric and place the engine upon opposite center, and the amount of lead should be the same on both steam ports, and the valve properly set.

The valve being set, replace the steam chest cover, and secure the eccentrics perfectly tight by screwing the set-screws up hard to prevent them from slipping.

Always set the valve so as to run the engine backwards or “under” first.

TO SET VALVES OF DUPLEX PUMP.

Set the pistons at mid-stroke, and set the valves which are worked from the opposite side at mid-stroke also, and it will be right at all other points. The mid position of the valve can be obtained by moving it back and forth the amount of its lost motion, and dividing it so that the lead or opening on both sides will be the same.

ASCENDING HILLS.

Q. How do you ascend a hill with a traction engine?

A. When approaching a hill which you have to climb with a traction engine, see that about two inches of water shows in the glass gauge when engine is on a level. Open draft door wide, stir the fire and get it to burn briskly, and get up a good head of steam. Put reverse lever in last notch, then open throttle gradually, allowing just the necessary amount of steam to pass into the cylinder to keep the engine pulling steadily up the hill. Always start up the hill slowly; do not attempt to go up a hill at full speed, but go slowly and steadily, keeping the speed as uniform as possible by opening or closing the throttle as the case may be. Never attempt to go up a hill on a decreasing steam pressure, as there is a great liability to become stalled, in which case great damage may be done to the front end of flues. Always start on a rising steam pressure; then you know the boiler is making steam, which assures a steady ascent, as at every exhaust of the engine on an increasing or steady pressure the power becomes stronger, while at every exhaust on a decreasing pressure the power becomes weaker. Keep a uniform supply of water in the boiler at all times by use of either the pump or injector. Always when going up hill keep the draft door wide open until the steam gauge indicates that the pressure has risen almost to the blow-off point, then close the damper. Never allow steam to blow off when going up hill, as it will cause the water to raise and be carried over into the cylinder, greatly diminishing the power of the engine. Do not under any circumstances allow your engine to be stopped when going either up or down hill, as great damage may be done to the boiler.

FRICK TRACTION ENGINE.

The illustration of the left side of the Frick Traction given on opposite page represents it as being a Center Crank, Rear Geared traction engine.

This engine is constructed with an overhanging cylinder, bolted to the cast iron engine frame, which contains the locomotive style guides and both pillow block bearings for the crank shaft. It has a Cross-head Pump connected with long heater, has a specially designed Reverse Gear, also a Friction Clutch attached to the band wheel.

The round bottom fire box boiler swings in a channel iron frame, which reaches from front axle to the rear of the boiler, around the fire box, to which it is attached, and has a spring in front end only.

The wheels are made entirely of iron, with forged spokes and wrought tire, with high mud grouters bolted on.

On the channel iron frame in front of fire box is placed a heavy plank, to which two large water tanks are attached on either side. The steering wheel and band wheel are on opposite sides of engine and it has all the necessary fittings, so that with proper handling it will be found perfectly safe and reliable. The platform in rear is also supported upon the channel iron frame.

DESCENDING HILLS.

Q. How do you descend a hill with a traction engine?

A. When approaching a hill which you wish to descend with a traction engine, see that the water in the boiler is at the regular height, or two inches in glass gauge when engine is on the level. Close the draught door to ash pan and open damper in smoke box when about to descend. Close the throttle almost tight, allowing just a little steam to enter cylinder, then take hold of the reversing lever, and the speed of the engine can be governed so as to descend at any speed desired, or be stopped, if absolutely necessary by throwing the lever into last notch.

Do not stop while going down hill unless absolutely necessary, as there is great danger of melting out the fusible plug and damaging the crown sheet, as the water is much lower over the crown sheet when going down hill with the required amount of water in the boiler than at any other time.

When it is absolutely necessary to stop the engine for a short time when descending a hill, do not turn on the pump or injector; but open the fire door, allowing the cold air to pass over the fire, which will protect the crown sheet. This should never be done, though, except in extreme cases.

ENGINE STALLED.

There is no standard rule by which a traction engine can be gotten out of bad places upon the road, as one rule would not apply to all situations, though a few suggestions on this subject may be beneficial.

When the engine is in a bad mud hole, or on a very sandy road, and the driving wheels will not take hold, but simply turn around, the best way to get out of the fix is to hitch a good team of horses to it and pull it out with what assistance the engine can give. Though in many cases, if a quantity of straw, stones or brush, as may be most handy, is placed under the driving wheels and the power applied, the wheels may get a footing and the engine will come out all right. Old boards or rails placed in the same manner will produce the same result.

It should be understood, however, that if the driving wheels do not take hold, but simply turn around in the sand or mud, the engine should be stopped at once and some of the aforesaid remedies tried. If you continue to work the engine under such circumstances, it will become more difficult to get out of the mire, as the wheels sink deeper in at every revolution.

CROSSING BRIDGES AND CULVERTS.

Before crossing a bridge or culvert with a traction engine, examine the stringers and floor carefully to ascertain whether it is in condition to hold the engine or not. If it appears a little weak, by laying heavy plank across for the traction wheels to run on, it may be crossed in safety, though the crossing of small bridges and culverts must be done with judgment, to prevent accident and delay.

FOAMING.

Foaming is the violent agitation of the volume of water in the boiler; it occurs only in dirty boilers and where dirty feed water is used, which causes the water to become saturated with foreign matter, such as lime, sediment, mud, oil or grease, etc.

The steam trying to escape through the scum formed by these impurities, raises the whole mass from the surface of the water in large bubbles, and causes a general frothing or foaming condition of the water level, which is indicated by the dirty appearance of the gauge cocks and joints and the cutting of piston rod and cylinder by the gritty matter carried over by the steam. Foaming does not result in carrying over so much water, but a foamy boiler does not produce as dry steam as one that is kept perfectly clean.

Q. How do you prevent a boiler from foaming?

A. To remedy foaming, or prevent it, requires frequent blowing off from the surface of the water the scum which causes it, and the use of pure feed water. It may be stopped for a while by closing the throttle valve for an instant, to give the water and scum a chance to settle.

PRIMING.

Priming in a steam boiler is the carrying over of large quantities of water by the steam to the engine, and may occur in a perfectly clean boiler. It is usually caused by too great a demand on the capacity of the boiler, too sudden and fierce firing, or after steam pressure is lowering, an increasing demand is made for it. It is usually a radical defect in the construction or capacity of the boiler, and is most frequently the result of insufficient steam space, small evaporating capacity, and lack of good circulation.

Priming is indicated by the water rising and lowering in the glass gauge more or less violently, by the clicking sound in the steam cylinder of engine as the piston forces the water from end to end, and by the regular shower of water falling from the exhaust.

Q. How do you remedy priming?