Abstract:
A gas compression apparatus and method according to which a compression cylinder is connected between two heads, and gas is introduced into at least one header and into the cylinder. A piston is reciprocated in the cylinder with a stroke corresponding to the length of the cylinder to compress the gas after which the compressed gas is discharged from the cylinder. If the cylinder bore becomes damaged or wears out, or if it is desired to change the stroke length of the piston, the cylinder can easily be replaced by disconnecting it from the heads and installing another cylinder between the heads.

Description:
BACKGROUND 
     This invention relates to a gas compression apparatus and method and, more particularly, to such an apparatus and method providing interchangeable compression cylinder sections allowing for changes in stroke or facilitating cylinder replacement. 
     Gas compressors having a piston that reciprocates in a compression cylinder mounted between two end heads are well known. Many designs of this type are utilize a single casting that includes the cylinder and the end heads which causes several problems. 
     For example when the cylinder bore is damaged or wears out, the entire casting must be removed from operation and hauled to a machine shop or the like. Also, if it is desired to use another cylinder having a different bore length to attain a different piston stroke length the entire casting must be replaced. 
     Therefore what is needed is a gas compressor system and method according to which the cylinder can be easily and quickly replaced with a minimum of down time. 
     SUMMARY 
     According to an embodiment of the present invention a compression cylinder is connected between two heads, and gas is introduced into at least one head and into the cylinder. A piston is reciprocated in the cylinder with a stroke corresponding to the length of the cylinder to compress the gas after which the compressed gas is discharged from the cylinder. If the cylinder bore becomes damaged or wears out, or if it is desired to change the stroke length of the piston, the cylinder can easily be replaced by disconnecting it from the heads and installing another cylinder between the heads. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a gas compression apparatus according to an embodiment of the present invention. 
     FIG. 2 is a cross-sectional view of the apparatus of FIG.  1 . 
     FIG. 3 is an exploded isometric view, on a reduced scale, of the apparatus of FIGS. 1 and 2. 
     FIG. 4 is an isometric view depicting a alternate compression cylinder that can be used in the apparatus of FIGS. 1-3. 
     FIG. 5 is a view similar to that of FIG. 1, but depicting an alternate embodiment of the gas compressor assembly. 
    
    
     DETAILED DESCRIPTION 
     With reference to FIGS. 1-3, a gas compressor assembly according to an embodiment of the present invention, is referred to, in general, by the reference numeral  10 . The assembly  10  comprises a pair of spaced end heads  12  and  14  connected together by tie rods  16  of suitable size and number to resist the gas loads. 
     An inlet manifold  20  is provided that has an inlet head  20   a  adapted to be bolted to a source of gas, and two branch conduits  20   b  and  20   c  connecting the inlet head to two outlet heads  20   d  and  20   e , respectively. The heads  20   d  and  20   e  are bolted to the upper surfaces of the end heads  12  and  14 , respectively, as viewed in FIGS. 1 and 2, and register with inlet openings formed in the upper surfaces. The latter inlet openings flange with two bores  12   a  and  14   a  (FIG. 2) formed in the heads  12  and  14 , respectively, which, in turn connect with two chambers  22   a  and  22   b , respectively, also formed in the heads, for reasons to be described. 
     An outlet manifold  24  has an outlet head  24   a  adapted to be bolted to a receptacle, or vessel, for receiving the compressed gas, and two branch conduits  24   b  and  24   c  connecting the outlet head to two inlet heads  24   d  and  24   e , respectively. The heads  24   d  and  24   e  are bolted to the respective lower surfaces of the heads  12  and  14  and register with outlet openings formed in the end heads. The latter outlet openings register with two bores  12   b  and  14   b  formed in the heads  12  and  14 , respectively, which, in turn, connect with two chambers  26   a  and  26   b , respectively. 
     A pair of covers  28   a  and  28   b  are partially shown in FIG.  2  and extend over the outer surfaces of the heads  12  and  14 , respectively, and are connected thereto in any known manner. 
     A cylinder  30  extends between the heads  12  and  14  with its respective end portions being registered in counterbores respectively formed in the corresponding side surfaces of the heads. Two gaskets  32   a  and  32   b  extend between the ends of the cylinder and the corresponding bottoms of the counterbores in the heads  12  and  14 , respectively. The bore of the cylinder  30  is aligned with through bores formed through the heads  12  and  14  to form a continuous bore, referred to, in general, by the reference numeral  34 . Although not shown in the drawings, it is understood that the chambers  22   a ,  22   b ,  24   a , and  24   b  communicate with the bore  34  through openings formed in the heads  12  and  14 . 
     Two heads  36  and  38  are mounted in the heads  12  and  14  to close off the ends of the bore  34 . The outer end portions of the heads  36  and  38  extend out from the respective surfaces of the heads  12  and  14 , and through corresponding openings formed in the covers  26  and  28 . 
     A piston  40  is mounted for reciprocating movement in the bore  34  and has a plurality of circumferential grooves formed in its outer surface for receiving a corresponding number of seal rings  42 . A piston rod  44  is disposed in the bore with one end portion extending into a bore formed in the piston and is connected thereto for driving the piston. The piston rod  44  extends through an opening in the head  36  and its other end portion extends out from the header  12  and the cover  26  (FIG.  1 ). It is understood that a prime mover, in the form of a motor, engine, or the like, is connected to the latter end portion of the piston rod  44  for reciprocating the piston  40  in the bore  34 . 
     As shown in FIG. 3, two bores  12   c  and  14   c  are formed in the upper portions of the heads  12  and  14 , respectively, are angularly offset with respect to the bores  12   a  and  14   a , respectively, and communicate with the chambers  22   a  and  22   b  (FIG.  2 ). Two valves (not shown) are mounted in the bores  12   c  and  14   c  and function in a conventional manner to control the ingress of gas into and through the bores  12   a  and  14   a , through the chambers  22   a  and  22   b , respectively, and into the bore  34  for compression by the piston  40  in a manner to be described. Similarly, two bores (not shown) are respectively formed in the lower portions of the heads  12  and  14  that are angularly offset with respect to the bores  12   b  and  14   b , respectively and communicate with the chambers  26   a  and  26   b . These latter bores also receive valves that control the egress of the compressed gas from the bore  34 , through the chambers  26   a  and  26   b  and the bores  12   b  and  14   b  for discharge through the manifold  24 , also in a manner to be described. 
     In operation, as the piston  40  reciprocates in the bore  34  in a direction from left-to-right as viewed in FIG. 2, gas from the manifold  20  is drawn into the bore  12   a  in the header  12  and into the chamber  22   a  under the vacuum caused by this movement. The gas then passes into the portion of the bore  34  extending to the left of the piston  40  under control of the valve in the bore  12   c . This movement also compresses the gas in the portion of the bore  34  extending to the right of the piston  40  and forces it from the latter bore portion, through the chamber  26   b  and the bore  14   b , and into and through the manifold  24  for passage to a storage vessel, or the like. 
     Similarly, as the piston  40  reciprocates in the bore  34  in a direction from right-to-left as viewed in FIG. 2, gas from the manifold  20  is drawn into the bore  14   a  in the header  14  and into the chamber  22   b  under the vacuum caused by this movement. The gas then passes into the portion of the bore  34  extending to the right of the piston  40  under control of the valve in the bore  12   c . This movement also compresses the gas in the portion of the bore  34  extending to the left of the piston  40  and forces it from the latter bore portion, through the chamber  26   a  and the bore  12   b , and into and through the manifold  24  for passage to a storage vessel, or the like. 
     The cylinder  30  can also easily be replaced with one that has a different length in order to obtain a different stroke length of the piston  40 . As shown in FIG. 4, a cylinder  30 ′ is provided that has the same diameter as the cylinder  30  but is of a longer length. The cylinder  30 ′ can easily and quickly be substituted for the cylinder  30  by removing the manifolds  20  and  24  from the heads  12  and  14 , and removing the cylinder  30  from the heads. The cylinder  30 ′ is then connected to the heads  12  and  14  in the manner discussed above, and the manifolds  20  and  24  are connected back to the heads  12  and  14 . In the latter contest the lengths of the manifolds  20  and  24  will have to be increased to accommodate the increased-length cylinder  30 ′. 
     Of course, in the event the cylinder  30  becomes damaged or wears out, it can easily be replaced with a new cylinder in the same manner as discussed above. 
     The embodiment of FIG. 5 is similar to that of FIGS. 1-4 with the exception that the manifold  20  has been replaced with two inlet ducts  50  and  52  having heads  50   a  and  52   a , respectively bolted to the upper surfaces of the end heads  12  and  14 , respectively, as viewed in FIG.  1 . The ducts  50  and  52  register with two inlet openings formed in the upper surfaces of the heads,  12  and  14 , respectively to introduce gas into the heads in the same manner as described in connection with the embodiment of FIGS. 1-4. 
     Similarly, the manifold  24  has been replaced with two outlet ducts  54  and  56  having heads  54   a  and  56   a , respectively bolted to the lower surfaces of the end heads  12  and  14 . The ducts  54  and  56  register with two outlet openings formed in the lower surfaces of the heads  12  and  14 , respectively to pass the compressed gas to a receptacle or vessel, also in the same manner as described in connection with the embodiment of FIGS. 1-4. 
     Otherwise, the embodiment of FIG. 5 is identical to that of FIGS. 1-4 and the additional components are given the same reference numerals. 
     The embodiment of FIG. 5 permits a two-stage operation according to which gas to be compressed is introduced into the inlet duct  52  and passes though the header  14  and into the bore  34  for compression by the piston  40 , in the manner discussed above. After it is compressed, the gas exits the header  14  via the outlet duct  56  and is reintroduced into the system  10  via the inlet duct  50  for further compression in the manner described above, before exiting via the outlet duct  54 . 
     The embodiment of FIG. 5 enjoys all the advantages of that of FIGS. 1-4 with respect to the relatively easy and quick replacement of the cylinder  30 . In addition, the ducts  50 ,  52 ,  54 , and  56  do not have to be replaced to accommodate cylinders of different lengths, such as cylinders  30  and  30 ′ but rather can be used in connection with cylinders of any length. 
     It is understood that references to “conduit”, “duct, “cylinder”, and the like are not meant to be limited to any particular fluid flow device and any such device or devices can be used throughout the system. Further, spatial references, such as “upper”, “lower”, “side”, etc. are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above. 
     Since other modifications, changes, and substitutions are intended in the foregoing disclosure, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.