Starting and unloading device

Application filed November 13, 1918. Serial No. 337,717.

To all whom, it may concern:

. Be it'known that I, Fbank B. Thomas,' a citizen of the United States, residing at Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented new and useful Improvements in Starting and Unloading Devices, of which the following is a specification. *

This invention relates to starting and unloading devices, and more particularly to an internal combustion engine starting and a fluid compressor unloading equipment.

Where an internal combustion engine is employed for driving a fluid compressor and the compressor is directly connected to the engine, if an electric starting motor is employed for starting the engine, it may happen that the compressor will be under load when the circuit of the motor is closed for starting the engine, in which case, the motor may fail to start the engine, due to the fact that the motor must then operate the loaded compressor as well as start the engine.

The principal object of my invention is to overcome the above difficulty, by providing means for unloading the compressor upon, operating the starting motor of the engine.

In the accompanying drawing; Fig. 1 is a sectional view of a starting and unloading 30 equipment embodying my invention; Fig. 2 a wiring diagram of the electric circuits; and Fig. 3 a diagrammatic view of the complete system.

As illustrated diagrammatically in Fig. 3, to chamber 8, a^valve 15 is provided, which is 55 adapted to be operated by a diaphragm 16, subject on one side to the pressure of an adjustable spring .17, and on the opposite side to the pressure in reservoir 3.

^For varying the fluid pressure in piston 60 chamber 9, a valve 18 is provided, which is adapted to be operated by a diaphragm 19, subject on one side to the pressure of an adjustable spring 20 and on the opposite side to the pressure in reservoir 3;

The unloading device · 2 may comprise a piston 21 having a stem 22 for operating the usual suction or inlet valve 23 of the compressor 24 and. the fluid pressure on one side of said piston is controlled by slide valve 13.

The electric switch device 4 may comprise a casing having a piston chamber 25, containing a piston 26, having a piston stem 27 carrying movable contacts 28, adapted to engage fixed contacts 29, for controlling an electric circuit 30, including an engine starting motor 31 and a source of current 32.

The admission and release of fluid under pressure to and from the piston chamber 25 is controlled by the magnet valve device 5, 80 which may comprise· a magnet 33, located in a shunt circuit 34, with the source of current 32, and valves 35 and 36 adapted to be controlled by said magnet.

Fluid under pressure is supplied to and 85 released from piston chamber 25 through a pipe 37 and communication from said pipe „_K ., , ., J , j said piston chamber is controlled by the the system included a starting motor 31, op- valve device^, containing a valve piston 38 eratively connected to the mam shaft 54 of subject on one side to the pressure of & an internal, coinbustion engine 55, the shaft spring 39, and on the opposite side to the 54 being direct connected to the fluid com- ------- ' ’ ‘ ” · -pressor 24. ,

The starting and unloading equipment, as shown in the drawing, comprises a compressor governor device 1, an unloading device 2, a reservoir 3, into which the compressor 56 compresses fluid, an electric switch, device 4, a magnet valve device 5, and a timing valve device 6, having a timing reservoir 7 connected thereto.

The compressor governor 1 may comprise a casing having piston chambers 8 and 9, containing pistons 10 and 11 which are connected by piston rod 12 for operating a slide valve 13, the valve chamber 14 containing said valve being connected to the reservoir 3.

For varying the fluid pressure in piston .40

7S pressure of fluid in the pipe 37.

In operation, if the pressure of fluid in the reservoir 3 is less than the cutting out pressure at which the governor 1 is adjusted, the, parts of the governor will be in the positions. shown in Fig. 1, since the diaphragm 19 will then be operated by the spring 20 to permit the valve 18 to remain in open position, in which position, fluid is vented 'from piston chamber 9, while the valve 15 will be held closed,- because the pressure of spring 17 exceeds the pressure of fluid from reservoir 3, acting on diaphragm 16 so that there is fluid under pressure in piston chain- IOS her 8, due to equalization of fluid through piston 10.

With the starting switch 40 in open poste

100

1,422,90S tion, as shown in Fig. 2, the magnet 33 will be deenergized, so that valve 35 will be closed and valve 36 opened to admit fluid from the reservoir 3 through passages 41 5 and 42, past valve 36 to passage 43 and thence past the check valve 44 to pipe 37.

The timing reservoir. 7 is then charged with fluid under pressure and when the pressure has. been raised to a predetermined 10 degree, the valve piston 38 will be operated to open communication from pipe 37 to piston chamber 25.

The piston 26 is then actuated to move the contacts 28 out of engagement with the 15 contacts 29 and thus open the starting motor . circuit.

If it is desired to start the internal combustion engine, the switch 40 is closed and the magnet 33 is thus energized, but the 20 circuit 30 of the starting motor 31 is still held open by the switch device 4.

The magnet 33 being energized, the valve 36 will be closed and valve 35 opened, so as to vent fluid from piston chamber 8, 25 through passage 45, past check valve 46 and past the valve 35 to the. atmospheric exhaust port 47.

The area of piston 10 being greater than the area of piston 9, the fluid pressure in 30 chamber 14, acting on the differential area of piston 10 will shift the pistons and slide valve 13, so that fluid under pressure is supplied from valve chamber 14 through passage 48 to piston 21, which is then actu35 ated to open the inlet valve 23 of the fluid compressor, thus unloading the compressor.

At the same time fluid is vented from the timing reservoir 7, through pipe 37 and the restricted port, past the valve 35, to the 40 exhaust port 47.

The restricted port 49 and the volume of reservoir 7 is such that after a predetermined time interval, ample to ensure the previous operation of the unloading piston 45 21, the pressure will be reduced sufficiently to permit piston 38 to be shifted to its lower seat by spring 39, so that fluid is vented from piston chamber 25 to exhaust port 50 and piston 26 is operated by spring 51 to 50 cause the contacts 28 to close the circuit 30.

The starting motor 31 is then energized to effect the starting of the engine, with the compressor unloaded.

As soon as the engine is started, the switch 55 40 may be opened, so as to stop the starting motor 31 and at the same time the magnet 33 is deenergized, thus causing the valve 35 to be seated and the valve 36 to be opened.

The exhaust from piston chamber 8 being 60 cut off by the closing of valve 35, fluid pressure equalizes from valve chamber 14 through the piston 10 to piston chamber 8, causing the parts to move, so that slide valve 13 connects passage 48 through cavity 52 with 05 exhaust port 53. Fluid is thereupon vented from piston 21, permitting the inlet valve 23 to close, so that the compressor will operate to compress fluid into reservoir 3.

At the same time, fluid is supplied, by the opening of valve 36, to- the timing reservoir 70 7, and when the pressure therein has been increased to a predetermined degree, the valve piston 38 is lifted to permit the flow of fluid under pressure to piston chamber 25. Piston 26 is then actuated to open the start- 7 5 ing motor circuit 30.

During the time that the engine is operating the compressor, the governor 1, operates to cut the compressor into and out of operation, so far as compressing fluid is concerned, 80 by operating the unloading device 2.

As the pressure in reservoir 3 increases by the operation of the compressor, a point is reached where the pressure is sufficient to overcome the pressure of spring 20, so that 85 diaphragm 19 is operated to close valve 18, · and when the pressure has been increased to the cutting out point, the diaphragm 16 operates to open¹ valve 15, so that fluid is vented from piston chamber 8, and the pis- 90 tons 10 and 11 then operate to shift slide valve 13, so as to open passage 48, for supplying fluid to piston 21. Said piston then operates to open valve 23 and thereby unload the compressor. 95

When the pressure in reservoir 3 becomes reduced, the valve 15 first closes and at a predetermined reduction in pressure the valve 18 is opened, so as to vent fluid from piston chamber 9 and thereby effect the 100 movement of the pistons 10 and 11 and slide valve 13. Piston 21 then moves so as to allow the valve 23 to seat and thereby cause the compressor to compress fluid into the reservoir 3. 105