BELTING.
Do not tax belts by overloading. Keep them free from accumulation of dust, grease and all animal oils, as these are injurious to both rubber and leather belts.
Special care should be taken to protect the edges of rubber belts from all animal oils, as they are liable to rot the belt.
Always run the grain (or hair) side of leather belts on the pulley, as it gives greater driving power, hugs the pulley closer, is less liable to slip, and will drive 30 per cent. more than the flesh side.
Rubber belts will be greatly improved and their life prolonged, by putting on with a brush, and letting it dry, the following mixture:
Equal parts of black lead and litharge mixed with boiled oil; add enough Japan to dry it quickly. In case the rubber peels off, the same mixture can be used.
In comparison to leather belts, 4-ply rubber is equivalent to a single leather belt and 6-ply rubber to double leather belt.
To find the length of a belt, add the diameter of the two pulleys together, divide the result by 2 and multiply the quotient by 3¹/₇; then add to this product twice the distance between the centers of shafts.
When piecing a belt when pulleys are changed, multiply the difference of the diameters of the pulleys by 1½, the product will be the length of the piece required.
The seam side of rubber belt should always be placed outside and not next to pulley. In case the belt slips, coat the side next to pulley with boiled linseed oil or soap.
In lacing a belt, begin in the center and be careful to keep both ends exactly in line. Lace both ends equally tight and do not cross the lace on the pulley side of belt. Great care should be taken that the ends butting together be cut perfectly square; if not, the belt will stretch more on one side than the other, which greatly impairs its worth.
Q. What is the practical limit of belt speed?
A. Belts should not be run much over 5000 feet per minute.
Q. How then is the capacity of a belt affected by its speed?
A. It varies directly as the speed. A given belt will transmit twice the horse-power if its speed is doubled within limits.
Q. Is the capacity of a belt affected by its width?
A. Yes, the capacity varies directly as the width. If a two inch belt will transmit one horse-power, two such belts will transmit two horse power; and this is true whether they are run separately or joined into a four inch belt.
To preserve cotton or Gandy belting, apply with a brush a little common paint to pulley side of belt while running, to be followed shortly afterwards by a little soft oil or grease to preserve its flexibility.
If the edges of the belt become frayed from the use of belt guides or forks, the loose threads may be cut off without injury to the belt.
If the belt slips at first, consequent to the surface being ruffled by unrolling, apply a little grease, oil or soap to the pulley side to make it grip.
Armington & Sims High Speed Engine.
ARMINGTON & SIMS HIGH SPEED ENGINE.
The cylinder and steam chest of this engine are cast in one piece and bolted securely to the engine frame, which forms the front cylinder head. The cylinder is lagged with mineral wool and jacketed to prevent radiation, and it is overhanging and self-lining.
The valve is a hollow piston valve, the body of which is steel tubing with cast iron ends. It receives its motion from the shaft governor, attached to one of the band wheels, which regulates the cut-off automatically according to the variation of load. The steam is exhausted at each end of the valve by very direct passages which quickly free the cylinder, preventing back pressure.
The engine frame is cast heavy and rigid, and contains the locomotive guides for cross-head and the pillow block bearings for the crank shaft.
The double disc center crank shafts allow of two small heavy band wheels being used.
The base of this engine is cast in one piece, to which the engine frame is securely bolted, and with this arrangement, the engine needs no expensive foundation.
The engine is simple and self-contained, ranging in sizes from 11 to 450 horse-power, and is intended to run at the very high speed of from two hundred to three hundred and fifty revolutions per minute according to size, and is used extensively in driving electric lighting machinery, and where high speed and continuous work is desired.