US1171017A - Fluid-compressor. - Google Patents

Description

J. S. BARNER.

FLUID COMPRESSOR. APPLICATION FILED MAR. 2. 1909.

1,171,017. Patented Feb. 8,1916.-

. 3 SHEETS-SHEET lj/EW 4 ATTORNEYS Tm. COLUMBIA PLANOORAPH co. WASHINGTON c.

I. S. BARNER.

FLUID COMPRESSOR.

APPLICATION FILED MAR-2.1909. 1,171,017.

Patented Feb. 8, 1916. W2

WITNESSES:

r/INV TOR m ATTORNEYS Tm: cvLuMmA ILANOGRAPII cuI. WASHINGTON, D. c.

J. S. BARNER.

FLUID COMPRESSOR.

APPLICATION FILED MAR. 2, I909.

1,171,017. Patented Feb. 8,1916.

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WITNESSES 53 INVENTOR B Y #UXM X W e ATTDRNEYS r l JOHN S. BARNER, OF ALBANY, NEW YORK.

FLUID-COMPRESSOR.

Specification of Letters Patent.

Patented Feb. 8, 1916.

Application filed March 2, 1909. Serial No. 480,927.

To all whom it may concern:

Be it known that 1, JOHN S. BARNER, a citizen of the United States, residing at Albany, in the county of Albany and State of New York, have invented certain new and useful Improvements in Fluid-Compressors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art, to which it appertains to make and use the same.

The object of the invention is to provide an improved air compressor and particularly one of the compound type commonly employed in connection with air brake systems.

The particular nature of the invention will best be understood from a consideration of the following description and the accompanying drawings.

In the drawings, Figure 1 is a central vertical section of the air compressor, Fig. 2 is a plan on an enlarged scale with the main valve chest in section, Fig. 3 is a section on the line 33 of Fig. 2, Fig. 1 is a detail illustrating the construction of the valve slide of Figs. 1, 2 and 3, Figs. 5 and 6 are detail sections at right angles to one another of an improved valve construction, Fig. 7 is a vertical central section of an air compressor embodying certain improved features hereinafter described, and Fig. 8 is a section like Fig. 3 showing the modified main valve in connection with the upper control valve.

The compressor comprises a high pressure steam cylinder 1 in which the high pressure piston 2 reciprocates, the piston 2 being connected by a connecting rod 3 to the piston of the high pressure air cylinder 5; together with a low pressure steam cylinder 6 in which the low pressure piston 7 reciprocates, the piston 7 being connected by piston rod 8 to the piston 9 of the low pressure air cylinder 10. In the particular construction illustrated, the compressor is built up of a number of castings including, the bottom plate 11, illustrated in Fig. 1, serving as a head plate for the high and low pressure air cylinders and containing the inlet and discharge ports and passages for the low pressure air cylinder; a casting 1 1 containing the cylinder chambers 10 and 5 and the discharge ports and passages of the high pressure cylinder; a central casting 16 containing the upper inlet and discharge ports and passages of the low pressure cylinder, and

v ally also carrying the stuffing boxes for the piston rods and the casing of the reversing tappet valve 17; the casting 18 containing the steam cylinders (3 and 1 and the steam passages; an upper end plate 19 forming the heads of the cylinders 6 and 1 and containing the continuation of the steam passages; and a valve chest 20 containing the main control valve which controls all of the steam passages of the high pressure and also of the low pressure cylinder, this valve chest being entirely removable from the upper end plate for convenience of repair.

The foregoing description applies generto the form of compressor illustrated in Figs. 1, 2 and 3 and also to the form of compressor illustrated in Figs. 7 and 8; but it will be observed that these compressors differ specifically from one another in that the inlet valves 12 of the low pressure cylinder illustrated in Fig. 1 are replaced by a series of inlet valves 18 controlling a series of inlet passages 49, in the construction illustrated in Fig. 7; and likewise the discharge valves 13 of the low pressure cylinder, and the discharge valves 15 of the high pressure cylinder, in Fig. 1, have been replaced by ball valves 58 and 59 of Fig. 7. Furthermore the main slide valve 21 of Fig. 1 is replaced in Fig. 7 by a piston valve 51.

The mode of operation of the compressor of Fig. 1 will first be described and then the nature of the modifications illustrated in connection with Fig. 7 will be set forth. Referring then to the compressor of Fig. 1, steam enters the main valve chamber 22, through the inlet pipe 23 from the boiler, between the pistons 24 and 25 connected to the stem 26 which carries the slide valve 21. From the main valve chamber 22 the steam is free to pass by passage 27 (see Figs. 2 and 3) into chamber 28 above the upper reversing tappet valve 22), holding it down and through by-pass 32 into chamber 33 to the left of piston Steam also passes from main valve chamber 22 by passage 35 into chamber 31 of reversing tappet valve 17 holding that valve up, and through bypass 36 and passage 30 into chamber 34: to the right of piston 21, thereby balancing the main slide valve 21. It will be understood that in this position the piston 2 is just beginning its upward stroke, so that during the upward stroke the pressures on pistons 21 and 25 are balanced and the slide valve 21 remains in the position illustrated,

downward stroke of to which it has already been brought in a manner which will understood from the following description. At this time steam is admitted directly from main valve chamber 22 beneath the piston 2 through passage 37, the exhaust steam above piston 2 passing through passage 39, recess d0 in slide valve 21 and passage ll to the low pressure cylinder above piston 7, and the exhaust from the low pressure'cylinder being through passage &2, recess in slide valve 21 and exhaust passageta to the exhaust pipe as (see Fig. 2). When the pistonreaches the upper end of its stroke the piston 2 strikes the stem of reversing tappet valve 29j'and lifts it, cutting off communication with the main valve chamber through by-pass 32 and opening a path for discharge of the steam in chamber 33 through passage 32, the lower portion ofthe tappet valve chamber below the piston, and'discharge orifice 45 directly to the exhaustat atmospheric pressure. This discharge of the pressure in chamber 33 destroys the balance of the main valve 21 and the pressure in chamber as throws the valve to the left, thereby putting passage 37 in communication with the lower end of the low pressure cylinder 6 through recess 43 in the slide valve ant passage 4:2. At the same time the upper portion of the low pressure cylinder 6 is open to the discharge port through passage l-1, recess -l0, and passage lt, and live steam is admitted directly above the piston 2 fromva'lve chamber 22 through passage In this way'the stroke of both the high'and low pressure pistons is reversed and when piston 2 reaches the lower end of its StifOli'G it valve 17, closing communication between chamber 22 and chamber and discharging chamber 34 through discharge orifice Hi to atmospheric pressure, whereupon the slide valve is returned to the position shown and the pistons are again reversed and the cycle of operations is repeated.

The operation of air compression, with the apparatus of Fig. 1, is as follows: On the piston 9 resulting from the downward stroke of piston 7, air is forced from the low pressure air cylinder 10 through lower valve 13 into the lower end of high pressure air cylinder 5, and at the same time air at atmospheric pressure is drawn through the upper inlet valve 12 above piston 9. By virtue of the fact that the high pressure air cylinder is smaller than the low pressure air cylinder, this results in a compression of the air to say about forty pounds, and this pressure aids in lifting piston i and piston 2, which are moving up ward. The upward movement of piston 4., against the forty pounds pressure in chamher 5 further compresses the air in that chamber and forces it through upper discharge valve 15 into the air reservoir which depresses tapp'et' may be connected to port 47 and uponreversal of the movement of the pistons the compression takes place in the opposite direction and the high pressure cylinder 5 discharges through lower discharge valve 15, as will be understood without any further description. It will be observed that with this arrangement, and using live steam at 200 pounds, exhausting at fifty pounds and with a compression by the lowpressure air piston of forty pounds, these figures being taken merely by way of example, there is acting to move piston 2 against the-air to be compressed the pressure-of the live steam, two hundred pounds, the pressure of the air coming from the low pressure cylinder, forty pounds, and against this, aside from the work of final compression, the pressure of the exhaust steam, namely fifty pounds, thereby giving a compressing force of about i one hundred and ninety pounds when using live steam at two hundred pounds. 7 l i By way of further improvement and simplification of the device, and for the purpose of further attaining the ficient service of the various parts for along time without replacement, I may substitute for the main slide valve of Fig. l, particularly when the steam is supplied under higher pressure, a piston valve like that shown at 51in Fig. 7, in which the slide 21 between the end pistons 2 l and 25 is replaced by a series of pistons 52 which serve to change the relative connections of the ports in the valve seat. In this case the live steam is not admitted directly to the valve chest and does not exert its pressure upon the movable valve, valve. On the contrary, to the connection 53 from the steam is piped which it passes by tween two adjacent pistons 52 on the piston valve stem, and it will act with equal oressure on both of these pistons so as not to disturb the balance of the valve. In the position of the parts illustrated in Fig. 7, which corresponds in general with the valve position illustrated in Fig. 1, the steam passes from passage 54 through passage 37 beneath'the high pressure motor piston 2 to raise that piston, and the low pressure steam above piston 2 passes through passage 39, between two pistons as shown, through passage 41 abovethe piston in motor cylinder 6, and from the lower portion of cylinder 6 the steam passes through passage 42, between the pistons of the piston valve'as shown, and through passage 55 to exhaust pipe 56. At the endof the stroke of piston 2 the tappet valve 29 is actuatedas in Fig. 1 to change the posi tion of the control valve and reverse the;

movement. In that case passage 54 is condesirable end of efas' 'in the case of a slide of the piston valve 7 there is only steam above piston 2; passage 37 is connected with passage 42 to lead the exhaust steamfrom below piston 2 to the bottom of cylinder 6, and the upper portion of cylinder 6 exhausts through passage 41 and passage 57 to exhaust pipe 56. It will be observed that in this case the mode of operation of the main control valve in conjunction with the reversing tappet valves is the same as in Fig. 1, but the main control valve is moved Without opposition and with very little wear, and with no possibility of hammering.

I have found that in the operation of air compressors, considerable difficulty is encountered with the operation of the valves, by reason of the fact that the ordinary type of valve is liable to become dirty and stick, break or leak, and to overcome this difliculty I prefer to employ, in the place of the valves 13 and 15 of Fig. 1, the type of valves illustrated in Figs. 5, 6 and 7. That is I substitute for these lift valves 13 and 15 commonly used, ball valves 58 and 59. Ball valves, by reason of their movement on their seats, will always present a clean surface of contact, and they tend to have a self-grinding effect on the valve seat to keep it perfectly round and true, and for these reasons alone the single ball valves might be employed to advantage, but it is important, particularly for the valves connected to the low pressure side of the compressor, to employ lighter valves than the commonly used lift valves, or than a single ball valve. To this end I form each valve seat of the valves 58 and 59 with a plurality of passages each of which is controlled by a separate small ball 58 and 59. Such valves are extremely light and practically indestructible, and are always tight, and it would be of advantage to employ them also in place of the low pressure inlet valves 12. I have, however, devised a further improved arrangement of the inlet passage to the low pressure cylinder, whereby atmospheric pressure is almost instantaneously obtained on the suction side of the piston. This arrangement is illustrated in Fig. 7 and is characterized by the fact that in addition to the inlet passages commonly employed, one at each end of the cylinder, I employ one or more intermediate inlet passages distributed along the length of the cylinder wall, and these passages admit air along the length of the cylinder to whichever side of the piston may at the moment be the suction side. These passages are illustrated at 49 in Fig. 7 and may conveniently be controlled by individual small ball valves 48 as shown, these passages being of sufficient extent to freely admit the air, and the ball valves being extremly light. In operation the upper passage 49 will commence to admit air as soon as the downward stroke of piston 7 begins, and as the intermediate passages 49 are passed by the piston in succession they will aid in admitting air above the piston thereby giving quick equalization. On the return stroke the lower passage 49 acts initially as the admission passage, and as the piston rises the intermediate passages 49 admit air to the lower side of the piston, which has become the suction side. I have illustrated four passages 49, the upper and lower passage and two intermediate passages, but it will be understood that the invention is in no way limited to that number.

What I claim is 1. In a compound fluid compressor, a high pressure motor cylinder, conduits for the motive fluid communicating with both ends of said cylinder, a low pressure motor cylinder, conduits for the motive fluid communicating with both ends of the low pressure cylinder, a main supply pipe for the motive fluid, and an exhaust pipe, and a single fluid-actuated control valve controlling all of said conduits and so arranged that in one position it connects the main supply pipe with the lower end of the high pressure cylinder, the upper end of the high pressure cylinder with the upper end of the low pressure cylinder, and the lower end of the low pressure cylinder with the exhaust, and in the other position it connects the main supply pipe with the upper end of the high pressure cylinder, the lower end of the high pressure cylinder with the lower end of the low pressure cylinder, and the upper end of the low pressure cylinder with the exhaust, conduits for supplying fluid to shift said control valve, and a tappet valve at each end of the high pressure cylinder in position to be actuated by the piston in its extreme positions, said tappet valves controlling the last named fluid conduits, in combination with a piston in each of said cylinders.

2. In a fluid-compressor, a motor cylinder with admission and exhaust ports and passages, a piston in said cylinder, a fluid actuated control-valve controlling said passages and having in ctmimunication with each side thereof a conduit for admitting fluid thereto and a conduit for discharging fluid therefrom directly to atmospheric pressure, and two tappet valves located at opposite ends of the cylinder in position to be actuated by the piston in its extreme positions and each controlling the admission and discharge conduits of one side of the control-valve.

3. In a fluid compressor, a motor cylinder with admission and exhaust ports and passages, a piston in said cylinder, a valve chest having a seat to which the said passages lead, a valve on said seat comprising a stem carrying end actuating pistons and intermediate separating pistons coacting ith a se to ang h r lati 11- ne ctions of the passages When the valve is shifted, said valve having in communication with its chz in ber outside of each. of the end pistons a conduit for admitting h to a d onf r' ie hersin fl i id. here ro and o ppet i 3 ma ted at opposite ends of th cylinder in pqsiigion to be actuated by the piston in its extreme

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