188 THE COLLIERY GUARDIAN. January 23, 1914. NEW TYPES OF AIR COMPRESSORS Some new types of power-driven air compressors have recently been put on the market by the Sullivan Machinery Company, of Chicago. In the first place, we may refer to a new series of small machines of the single-stage type, for operation by belt, for stationary and portable work respectively. The belt-driven type of compressor consists of a single air cylinder, securely bolted to a sturdy frame, which carries a crank shaft having a belt pulley on one end, and a flywheel on the other. Counterbalances on the cranks aid the compressor to run smoothly, with little vibration or strain upon moving parts. An unloading device on the air inlet valves saves power when the demand for air is less than the output of the machine. The shaft is supported in removable, die- cast babbitt bearings, which are carried by seats in the frame, accurately bored out. The crosshead is a strong g: r Fig. 1.—Sullivan Motor-Driven Air Compressor on a Mine Truck. possible degree losses in air delivery, due to clearance space. Lubrication of the air cylinder is furnished by a high grade sight-feed air cylinder lubricator. All moving parts outside the cylinder are oiled by a “ splash system ” from a reservoir of oil under the crank shaft, into which the cranks and connecting rod dip. In the portable type there are suitable alterations in driving attachments and mountings, the compressor, motor and receiver being bolted to the bed of a mine car or special truck. This type is found a convenient means of converting electric power into air power for the operation of coal pick machines in headings, of air drills, in workings remote or difficult of access. Fig. 1 shows an outfit of this character, supplied for coalmining service, complete with receiver, unloading valve, starting rheostat and main line switch. These compressors are built in two sizes, with cylinders 8 by 8 and 10 by 10 inches in size, providing a displacement each end with coupling connections, and has flanged wheels, mounted on steel axles. The gauge of the wheels will vary to fit the customer’s track. The following shows the dimensions of the portable type Cylinder— Diameter Stroke in. 8 .. in. 8 .. 10 10 Piston displacement— Per revolution cu. ft. 0 466 .. . 0 905 Per minute ,, 98 .. . 181 Revolutions per minute 210 .. . 200 Terminal air pressure .. lb. 100 .. . 100 Horse-power at belt.... 17 5 .. . 37 Dimensions— Length ft. in. 6 10 .. . 8 0i Width „ *4 51.. . *5 If 3 10 .. . f-4 9-j Height above rails ... 3 8i.. . 4 6 Flywheels— Diameter 3 11| ....in. 34 ... . 42 Width of pulley face ...in. 4 ... 5f Piping- Air inlet ....in. 2i ... 3| Air outlet ....in. 2 3 Jacket water 2 • • 4 * Direct-current motor. + Alternating-current motor. Angle-Compound Compressor. The Sullivan Company are also supplying an “angle- compound ” compressor for belt or direct drive. As shown in fig. 2, the angle-compound air compressor has its low-pressure or intake cylinder in a horizontal plane, with the high-pressure cylinder set vertically, on the end of the horizontal frame. Both pistons are actuated by a single crank, and both sets of valve gear by a single eccentric pin. The driving pulley or motor is mounted at one side, on an extension of the crank shaft. The anglo-compound design permits a very close balancing of reciprocating masses. The intercooler used is of unusually large relative size, and has some special features, including the use of the outside walls of the cylinder water jackets for cooling the air. A single crank pin takes the place of the two eccentrics cus- WATER OUTLET- Fig. 2.—Sectional Elevation of Angle-Compound Compressor. SULlIWii Fig. 3.—Sullivan Angle-Compound Air Compressor in a Steel Foundry. casting, provided with removable shoes, whose faces are turned to fit the bore in the frame. These shoes seat on the crosshead on inclined machined surfaces, so that adjustment for wear on both top and bottom guides is gained by sliding the shoes along their seats by screws provided for the purpose. The crosshead pin is of selected steel, accurately ground to a taper fit in the crosshead body. The air cylinder barrel and heads are completely surrounded by water jackets to reduce the heat of compression, and the water spaces are provided with drain cocks. The air cylinder piston is of ample size, closely fitted to the bore of the cylinder and furnished with expanding spring rings. The inlet and discharge valves are automatic poppet valves, set close to the ends of the cylinder, the inlet valves being at the bottom and the discharge valves at the’ top of the cylinder. As these valves act in a radial direction to the axis of the cylinder, they avoid to the greatest capacity, respectively, of 98 and 181 cubic feet of free air per minute, against a terminal air pressure of 100 lb. This capacity is ample to operate one or two small reciprocating rock drills, several hammer drills or pneumatic tools, or, in the case of the larger unit, a coal pick machine or post puncher. A single fly-wheel, fitted with internal gearing, is provided, this gear meshing with the driving pinion on the motor shaft. The motor varies in type and rating, depending on local conditions of current, voltage, &c. An air receiver, made of steel plate and of first-class construction, is shown by the illustration. It is tested and made tight under 150 lb. cold water pressure, to withstand a working air pressure of 100 lb. The compressor, motor and receiver are mounted on and securely bolted to a sub-base, which forms the frame or body of the truck. This base is a strongly- ribbed casting of abundant strength. It is fitted at tomarily used for driving the valve motion in duplex machines. A balanced disc on the end of the crank shaft carries a crank pin on which the connecting rods are hung for the valve motion of both cylinders. In the angle-compound compressor, it is claimed, the disturbing influences of the horizontal and the vertical members tend to offset or neutralise each other, the maximum unbalanced effects of the vertical parts being produced when those of the horizontal parts are at minimum value, and vice versa. The heavy counter- weight permitted by the design practically absorbs within the shaft itself all of the heavy inertia loads which would otherwise have to be carried by the crank- shaft bearings, and leaves these important elements of the compressor free to perform their proper function of carrying the load due to the air pressure on the pistons and to support the weight of the moving parts In addition, a further benefit is gained by a more uniform