US1951751A - Gas compressor - Google Patents

Description

March 20, 1934. H, c, COPE 1,951,751

I GAS COMPRESSOR' Filed Sept. 4, 1931 s Sheets-Sheet 1 INVENTOR Mar h 0, 1934. H. c. COQPER GAS COMPRESSOR Filed Sept. 4 1931 a SheetsL-Sheet 2 Patented Mar. 20, 1934 UNITED STATES v GAB COMPRESSOR Howell C. Cooper, Pittsburgh, Pa., assignor to 8.

B. Dresser Manufacturing Pennsylvania (30., a corporation of.

Application September 4, 1931, semi him 561,095 V Claims.

This invention relates to improvements in gas compressors, and, while 0! general applicability where gases and vapors are to be compressed, it finds practical application in compressors em- 6 ployed in the transmission of natural gas through pipe lines for distances in th order of hundreds and even of thousands of miles. The object of the invention, as it has been developed in the field indicated, is economy, both in the installa- 10 tion of and in the maintenance of such apparatus.

In piping natural gas across country for distances oi the order indicated, it is necessary to maintain at intervals compressing stations, or booster stations, as they are called, where the is flowing gas is compressed to high degree. The pressure requisite to flow diminishes along the course of. the stream, and must be renewed, in order to eileot transportation on commercial scale.

go It is a practical necessity that the engines employed at the booster stations be internal combustion engines: economy oi operation is determinative on that. point. The compressor unit of present practice includes a pair of axially aligned power and compression cylinders. As demand increases such a unit may be built larger and heavier, until at length practical limitations in matters 0! weight and speed are approached, and.

then resort is had to multiplication of units. In so common practice, as many as six such units make up the working equipment of a booster station, and the stations succeed one another-at intervals 0! about eighty miles. Further demands can then. be "practically satisfied only by installing more as booster stations; by establishing them at shorter intervals. The investment in such an installation is relatively great.

The invention is ioundin a compressor unit of diii'erent organization, capable 0! operation at 40 much higher speeds than the compressor unit oi present practice alluded to above, so constructed that it will be much lighter in weight and will occupy much less space than the present-day unit oi equivalent capacity; the unit of this invention may be moved economically in its entirety, when of buildings to house the machines.

of foundations, in erection costs, and in the cost And these are matters of peculiar importance in remote regions, through which pipe lines not inirequently are laid. 69

In the accompanying drawings, Figs. I and H are opposite end views in elevation of a compression unit of my invention; Fig. III is a view to larger scale, showing the unit in axial section, on the plane indicated at BI -III, Fig. I; Fig. IV is a fragmentary view in transverse section, on the plane indicated at IV-IV, Fig. III. The moving parts are shown in Figureslli and IV positioned at different stages in the cycle oi .operation. Figs. V-IX are fragmentary sectional 70, views on the sameplane with Fig. IV and which,

when considered in connection with Fig.- IV, will serve to illustrate operation; and. Fig. X is a fragmentary view in section, on the plane indicatcd at X-X, Fig. 111.

The shait l of the unit, mounted in suitable bearings, is driven by the pistons 3 of a plurality of radially arranged power cylinders 2.]

of a plurality of radially arranged compression cylinders 7. The shaft 1 is provided witha flywheel 8. Radial arrangement in this art has 35. come to mean a grouping oi threeor more cylinders, spaced at equal intervals, circumierentially around the shaft. The axes of three or more cylinders so grouped necessarily lie in a plurality of radial planes (radial with respect to the shaft axis), as distinguished from the condition which obtains in case no more than one or two cylinders be employed; and in those cases the axis of the one cylinder or the axes of the two lie in a single radial plane. The power cylin- 9 ders which engage the crank 4 are, as here shown (Fig. II), eight in number, and the compression cylinders, engaged by crank 5, three (Fig.

I) it will, however, be understood that the number of cylinders in each group may be varied 109 from three as a minimum upward. One group oi power cylinders is shown in the drawings and one, group of compression cylinders; and it will be understood that the number of groups of either sort may be multiplied. The shaft is shown to be simple, its two parts united .by the hub of.

the fly-wheel; it willbe understood that it in the term shaft member used in the claims. These are matters of engineering, which need only to be mentioned in order to be understood.

The distinguishing feature of the radial arrangement, that the cylinder axes lie in a plurality of radial planes, is attended by thistechnical eifect, that at every point in the range of shaft rotation tendencies to displacement under inertia are positively resisted and renderedineffective. And I have found that by adopting this radial feature in the construction and arrangement both of the power cylinders and of the compression cylinders, I am able, as otherwise I should not be able, practically to attain those high speeds which render my unit economically advantageous in this art.

throimh the gear-shaft 11.

Each cylinder 2 with its piston 3 and associate parts maybe understood to constitute an internal combustion engine of two-cycle type. It is not essential to the invention that the engine be of two-cycle type; that type is chosen by way of example, merely.

The valve mechanism, for controlling the flow of gas to and from the compression cylinder is mechanically operated: that is to say, it is positively driven, in response to the rotation of shaft 1. Preferably, and as here shown, the valve is of rotary type. Each cylinder-7 is closed at its outer end by a valve-chest 9, within which is arranged the cylindrical rotary valve 10. The inlet and discharge passages through the valvechest are shown in Figs. IV-IX, and the direction of flow is, in Fig. IV, indicated by arrows. Rotation of valve 10 is effected from shaft 1 The valve, it will be remarked, is double, in that it includes duplicate and symmetrically arranged parts: in the course of one complete rotation, therefore, it repeats twice over its cycle of cooperation with the passages through the valve-chest. And the valvedriving gearing is so proportioned that the valve rotates at just one half the speed of shaft 1.

Rotary valves, heretofore proposed, have not gained acceptance in the practical art because of the leakage present in their operation, a feature which cannot be eliminated. For my purposes, however, a rotary valve is useful as valves of other type are not, because it is reliable at high speed, and, as I have said, it is at high speed that the practical value of my arrangement is realized. The leakage inevitably present in the rotary valve may be made slight, and this slight leakage is an inconsiderable matter, in view of the great practical gains incident to my characteristic high-speed operation.

The direction of valve rotation, as viewed in Figs. IV-IX, is clockwise, and these figures show successive positions in the course of a half rotation of the valve. During this half rotation the piston 6 within the cylinder 7 makes a coma duplicate cycle of operation, while the piston 8 within cylinder '7 repeats its down-and-up reciprocation.

Beginning with the parts in the positions shown in Fig. IV, the valve 10, turning clockwise, having previously cut of! delivery from the cylinder through the valve to the discharge from the valve chest, is now at the point of opening communication from the intake through the valve to the cylinder 7; and pistonv 6 has already started down (in the direction indicated by an arrow) from Such variation will be understood to be included" the upper limit of its range of reciprocation. IV, V, and VI show the range of turning of the valve while the piston operates during the suction period. At the end of the suction period, the turning valve comes to the position shown in N Fig. VI. The piston on its up stroke compresses the gas. In the course of the up stroke of the piston communication through the valve to the discharge from the valve chest gradually opens and closes again, as shown in Figs. VII, VIII, and IX. (The closing actually may be deferred, and may occur just after the piston has begun its down stroke.)

Rotary valves have not in general been found to be satisfactory heretofore, because they may not be made tight enough; automatic reciprocating valves which, because they may be made tight, are generally preferred, are incapable of service at very high speed. I have found that, working at high speed, tightness is of less importance, and that the rotary valve is adequate.

In adapting the apparatus to use in the compression of gases which are inflammable-and natural gas is inflammable-provision is made, to prevent the accidental formation of an explosive mixture in the crank case. A crank case, whose walls are indicated at 12, encloses the crank 5 upon shaft 1. Into this crank case some gas necessarily will find its way by leakage past the pistons 6. The crank case is rendered prac- 10 tically gas-tight by the bearings for the shaft 1 which are mounted in the walls of the case; in order, however, to prevent ingress of gas to the adjacent casing chamber on the left (as seen in Fig. III), a gas seal 13 is at that point provided. Through the crank-case walls, pipe connections 14 and 15 are carried, and through these gas of suitable nature (conveniently, natural gas) and at a pressure greater than atmospheric may be circulated; thus, within the casing 12 a body of 11 gas at a pressure slightly exceeding atmospheric may be maintained, filling the crank case to the exclusion of air.

Gas at low pressure from the pipe line enters the valve chest at the intake (from the left, Fig. 1 IV) and gas at high pressure is delivered from the valve chest through the discharge (on the right). In this particular unit, with three compression cylinders '7, it will be understood that the stream of gas advancing through the pipe line is, at the booster station, subdivided into three parts, and that one third of the whole passes, through each compressor cylinder 7. It will, however, be understood that more than one such unit may be in simultaneous cooperation at a "booster station, and that in such case the total stream will be correspondingly subdivided.

To one heavy shaft the driving impulses of a plurality of engine elements are imparted, and the power of that shaft is applied to the total 186 volume of gas through a plurality of compressor elements, each acting upon a fraction of the whole. The economies effected by this novel compressor unit are of the nature indicated.

I claim as my invention:

1. In a gas compressor the combination of a rotary shaft member, a plurality of three or more engine elements radially arranged with respect to said shaft member and engaging said shaft member through a common crank, a plurality of 145 three or more compression elements, including each cylinder and a piston, radially arranged with respect to said shaft member and with the pistons of which said shaft member is through a single crank connected, a plurality of valves lei) associated, one with each of said compression elements, and controlling the flow of gas to and from the compression elements with which they severally are associated, and meansfor driving the valves in response to rotation of the. shaft rnemher.

2. In a gas compressor the combination of a rotary shaft member, a plurality of three or more engine elements radially arranged with respect to said shaft member and engaging said shaft member through a common crank, a plurality of three or more compression elements including each a cylinder and a piston radially arranged with respect to said shaft member and with the pistons of which said shaft member is through a single crank connected, a valve chest and a rotary valve within it associatedwith the cylinder of each compression element and means for rotating the valves in the valve chests in response to rotation of the shaft member.

3. In a gas compressorthe combination of a shaft, a compression cylinder, 8. piston in said cylinder, operative connection between said shaft and said piston, a crank case enclosing said operative connection, a gas intake opening to .the

cylinder on the side of the piston remote from the shaft and beyond the range of piston traverse, and additional means for supplying. to and for maintaining within the crank case a body of air.-

excluding gas.

4.111 a gas compressor the combination of a shaft, a crank borne by the shaft, a compression element including a cylinder and a piston radially 'cmmcm or coinircrion.

Patent No. 1,951,751.

nowm. c. coorm.

arranged with respect to said shaft. the said piston being operatively connected to said shaft, a crank case enclosing said crank and crank connections and the adjacent portions of the shaft and the proximate end of the said cylinder, means for admitting gas to and permitting discharge of gas from the remote endof said cylinder, such means being arranged beyond the range of piston traverse, and additional means arranged on the opposite side of the piston and beyond its range of traverse in opposite direction for supplying to and for maintaining within the crank case a body of airexcluding gas.

5. In a gas compressorthe combination of a shaft, a crank borne by the shaft, a plurality of compression elements grouped radially about the shaft, each including a cylinder and a piston, all of the pistons of the said'elements being operatively connected to the said crank which serves them in common, means arranged beyond the outer ends of piston traverse for admitting gas to and permitting the discharge of gas from the ends of the cylinders remote from the shaft, a

It is hereby certified that error appears in theprinted specification of the above numberedpatent requiring correction as follows: Page 2, line 147, claim '1, after "each" insertthe article a; and that the eeid'Lettere Patent should be read with this correetiontherein that theme may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of May, A. D. 1934.

(Seal) March 20, 1934.

Bryan M. Battey Acting Conmieei'oner. of Patents.

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