Gas compressor

Abstract: The invention provides a gas compressor (10) comprising: a single, straight, walled cylinder (12) having (a) a longitudinal axis (14), and (b) a single, circumferential wall; and headers (20, 24) at opposite ends of said cylinder (12); wherein one of said headers (20) has a tapped hole (28) formed in a surface thereof which opens onto said cylinder (12); the other of said headers (24) has a tapped bore (38) opening therethrough; and a first inlet vlave (30) threadedly engaged with said tapped hole (28) and confined within said cylinder (12); a second inlet valve (30a) threadedly engaged with said tapped bore (38) and confined within said cylinder (12); said second inlet valve (30a) has a throughgoing bore formed therein which is coaxial with said tapped bore (38); a piston rod (40) in penetration of said bores, and having one end thereof projecting outwardly from said other header (24); a pair of discharge valves (46, 46a) coupled to said piston rod (40), and spaced apart along said rod (40), confined within said cylinder (12); gas inlet ports (50, 50a) radially formed in said cylinder (12) at opposite ends thereof; and a gas outlet port (52) formed in said cylinder intermediate said ends thereof.

Description: This invention pertains to gas compressors, and in particular to a gas compressor of novel design in which the compression cylinder thereof confines therewithin both the inlet and discharge valves, and the latter valves are piston ringed to serve as the gas compressing pistons. Conventional, prior art gas compressors require inlet and discharge valves, and gas compressing pistons. Too, commonly, the valves are external to the compression cylinder. US-A-1,568,776 discloses a straight cylinder gas compressor having a cylinder with an inlet at its central portion for air or gas and outlet valves near the ends of the cylinder for the discharge of the compressed air or gas. The present invention is as claimed in claim 1. It is an object of this invention to set forth a novel gas compressor which obviates any need for separate pistons, and such a compressor of simple, albeit efficient configuration. Further objects of this invention, as well as the novel features thereof, will become more apparent by reference to the following description, taken in conjunction with the accompanying figures, in which: Figure 1 is a perspective illustration of a gas compressor, according to an embodiment of the invention, the same being partly cut away along the axis thereof; Figure 2 is a perspective illustration of the piston rod assembly of the Figure 1 embodiment, the same also being cut away in part; Figure 3 is a partly cut away perspective illustration of the cylinder and porting; and Figures 4 and 5 are cut away depictions of the frame header assembly and outer header assembly, respectively, showing the tie rods and the inlet valves. As shown in the figures, the novel compressor 10 comprises a straight cylinder 12, having a longitudinal axis 14, with shouldered recesses 16 and 18 at opposite axial ends thereof. An outer header 20, having a prominent, circular land 22 in the centre thereof, is set, with an O-ring for sealing, into the recess 16. Similarly, a frame header 24, which also has a prominent, circular land 26 in the centre thereof, is set too with an O-ring for sealing, into the recess 18. The header 20 has a tapped hole 28 formed in the land 22. An inlet valve 30, having a threaded stub 32, is threadedly engaged with the hole 28. Valve 30, of the one-way, check type, has an annular body 34 with piston ring grooves 36 formed thereabout (in which to receive piston rings). The land 26 in the frame header 24 also has a tapped bore 38 formed therein; it threadedly receives a second inlet valve 30a. Valve 30a, however, is centrally bored to accommodate therethrough a piston rod 40. The piston rod 40 penetrates the tapped bore 38 and is slidably engaged with the central bore in the valve 30a. One end of the piston rod 40 projects outwardly from the header 24, via one end thereof, and into the cylinder 12 via the opposite end thereof. The termination of the in-cylinder end of the rod 40 is threaded; too, intermediate the length of the rod 40 there is a shoulder 42. A tubular spacer 44, internally threaded at one end thereof, and externally threaded at opposite ends thereof, is set against the shoulder 42, and threadedly engaged with the threaded termination of the rod 40. A pair of discharge valves 46 and 46a, the same having annular bodies 48, are centrally threaded and threadedly engaged with external threads of the spacer 44. Valves 46 and 46a, too, are of the one-way, check type, and also have piston ring grooves formed thereabout in which to nest piston rings for sealing against the inner surface of the cylinder 12. A pair of inlet ports 50 and 50a are formed in the cylinder 12, adjacent to the axial ends thereof, the same opening onto the inlet valves 30 and 30a. Intermediate the length of the cylinder 12 there is also formed a single discharge port 52. Ends of the cylinder 12 abut the headers 20 and 24 and nest, in grooves formed therefor, O-ring seals 54. Tie rods 56, fastened in the header 24, and in penetration of the header 20, receive nuts 58 on the threaded ends thereof and clamp the cylinder 12 and the headers 20 and 24 securely together. Inlet conduits 60 and 60a are welded to the cylinder 12 for communication with the ports 50 and 50a, and a discharge conduit 52 is similarly welded to the cylinder 12 for communication with the discharge port 52. The simplicity of the configuration of the compressor 10, in this embodiment thereof, can readily be seen; the same offers manufacturing and maintenance ease. More significantly, pistons per se are not required, as the valves 46 and 46a serve the double purpose of piston-compression of the gas, and valved discharge of the compressed gas. Only inlet and discharge ports need to be formed in the cylinder 12, as the valves 30 and 30a, and 46 and 46a are confined within the cylinder. The headers 20 and 24 fit firmly into the ends of the simple, straight cylinder 12, and only tie rods are required to clamp the assembly together.

Claims: A gas compressor (10), comprising: a single, straight cylinder (12) having (a) a longitudinal axis (14), and (b) a single, circumferential wall; and solid headers (20, 24) secured to opposite axial ends of said cylinder (12); wherein one of said headers (20) has a tapped hole (28) formed in a surface thereof which opens into said cylinder (12); the other of said headers (24) has a tapped bore (38) opening therethrough, centrally thereof; and a first inlet valve (30) threadedly engaged with said tapped hole (28) and wholly confined within said cylinder (12); a second inlet valve (30a) threadedly engaged with said tapped bore (38) and wholly confined within said cylinder (12); wherein said second inlet valve (30a) has a throughgoing bore formed therein which is coaxial with said tapped bore (38); a piston rod (40) in penetration of said bores, and having one end thereof projecting outwardly from said other header (24); a pair of discharge valves (46, 46a) coupled to said piston rod (40), and spaced apart along said rod (40), confined within said cylinder (12); and gas inlet ports (50, 50a) radially formed in said cylinder (12) adjacent opposite ends of said cylinder, opening directly onto said cylinder-confined inlet valves (30, 30a); wherein said piston rod (40) has a shoulder (42) formed thereabout intermediate the length thereof, and is externally threaded at the end thereof which is opposite said projecting end thereof; and further including a tubular spacer (44), internally threaded at one end thereof, externally threaded at opposite ends thereof; wherein said spacer (44) is set about said opposite end of said piston rod (40), having an end thereof abutting said shoulder (42), and said internally threaded end is threadedly engaged with said opposite end of said piston rod (40); said discharge valves (46, 46a) are centrally bored and threaded, and are threadedly engaged with said externally threaded ends of said spacer (44); and a gas outlet port (52) formed in said cylinder intermediate said ends thereof. A gas compressor, according to claim 1, wherein: said first inlet valve (30) has an externally threaded stub (32) extending therefrom, centrally thereof; and said threaded stub (32) is threadedly engaged with said tapped hole (28) for fixing said first inlet valve within said cylinder. A gas compressor, according to claim 1, wherein: said discharge valves (46, 46a) have annular bodies (48); and said bodies (48) have piston ring grooves formed thereon to accommodate therein piston rings for effecting sealing engagement with said cylinder (12). A gas compressor, according to claim 1, wherein: opposite axial ends of said cylinder (12) have shouldered recesses (16, 18) formed therein; said headers (20, 24) have circular lands (22, 26) in the centres thereof; and said lands (22, 26) are set into said shouldered recesses (16,18).

Inventors: BENNITT ROBERT ARTHUR, BENNITT, ROBERT ARTHUR
Applicants: DRESSER RAND CO, DRESSER-RAND COMPANY
Application year: 1991
Main classification: F04B5
IPC codes: F04B5, F04B3