US2667299A - Compressor inlet valve actuating mechanism - Google Patents

Description

COMPRESSOR INLET VALVE ACTUATING MECHANISM Filed April 14, 1950 INVENTOR.

AL ED N. G TAFSON (2 zg' TTORN S.

Patented Jan. 26, 1954 UNITED STATES PATENT erric-E 2 667,299 ooMPa-E s-soa -'IN LET vALv-E AoT Armo M A IS Alfre r fiustafson, :West .Chester, Ra assisnor o S hran m .Ine W )Qhester; Fa a po norat nof R nnsylvan Application April 14, 1950, Serial No.-155;968

(Cl. 239x30) 3 Claims. 1

This invention relates to valve assemhlies fo compressors and particularly to valve assemb ies for such compressors as are provided .by the 1693-? version of the parts of an internal combust engine.

Compressors of reciprocating piston type may he provided by the conversion of {the valve arrangement of what may be gbasically considered an internal combustion engine, :In some casesall of the cylinders of anensine may 'b so conv r ed :to compr s cyl der in which ease th relt mpr so i driv n by an ther en n o mo or alte na vely, on y some o the cyl ns of a mu i-e linder n ine may b so eo.n yerted s that a c mbinat on ensine e m nessor e u In a y ve t, th c nve sion i adva ta eous t h manu a tu er i that e ma or pa f m essors n e ines ma e subst i v i e t c with the or re e suf e i f m th engine o ly the matt of t valve assemblies.

In my Patent ,2,l,O,860, dated June 6, 1939, there is llu tra d a ers o for a L head type of engine to a compressor, the conversion being possible forall of the cylinders or only some of them as just indicated. This patent shows the arrangement of both inlet and dis.- charge valves and shows also the provisions for unloading by maintaining the inlet valve cont nu sly p n whe the p ess the rece ver reaches some predetermined set value. Consid,- ering fi t th inlet val e sse b y f the p tent, the inlet valve, opening npwardly, may be limited in its opening movement qpite readily by enga em w t a t o th n osineshel arrangement, however, is not practical in a valve-in-head type of compressor that the clearance between the inlet valve and its cont-e.- sponding piston is maintained at a minimum. accordance with the present invention provision is made for the proper unloading control of an inlet valve in a 'valve-inhead type of engine. Du n the unl adin p d th cam cont nues to reciprocate the inlet valve but its range of movement is changed so that it reoiprocatesin a cont nu us. y o pos t Dnrine h i loaded period air flows inwardly and outwardly past the inlet valve without the production of any substantial compression in the q 1y ,i I 1=1- I at in th result the am follower to h inlet valve i ef e t e n ated- The invention also relates to improvements in the discharge valve assembly. lnmy patent the discharge valve assembly is :held position by a set screw, which arrangement :has various w.disa vantase particularly in that it is oimcult for an'unslgilled operator to set the set screw properly :to Gn ure a pr per operatin os of the discharge valve assembly. In accordance with the present invention an improved arrangement $101 and op ration, will :become apparent af. the Q1t19Wi lg' description read in conjunction with he accompanying drawing, in which the figure illustrates in fragmentary vertical section the valve assemblies associated with a single cylinder of the compressor, together with the poet-ml arrangements for unloading the inlet va ve- Eor simplicity of description the invention will he described as applied to a in l yl n r, it being understood, of .course, that duplicate ar- ;1 anse me ts of the valve assemblies will "be proid d QQnilmct-i n with all of the cylinders if 3:11:91 the cylinders of a pa ul unit are PIQSSOI cylinders. or will be applied to some of the cylinders which are utilized for compression ;1n; a unit which is in part engine and in part @QHJDIQfiSQ "Iheey 'nderlolockfl is provided with a cylinder 4 in wh ch reoiprocatesthe piston 6. The cylinder is closed by the cylinder head 8 which is secured to the block with interposition of the #51 84 aske :19. inlet valve l2 seats at M and uid d through -:a stem :g i l6 b in ur ed upward y toward seate o tion :by a spring [8. The inlet air passage is indicated .at 13. Thhficfi 210 carr es ocker arm .22 whi h engages th r er o the va e stem, anais provided with an adjustable screw 2.4 engaging r p er end o the pos rod 2,6, the lower lend 2!! of which i rece ed a socke i a mean ,slidahle ina io lfnder AO- Ihe isto 30 is p ovi ed ,W' i'h a sk t .32 harms opf loss .34 therein. hi snrt a; ine the bore 3; i i albw'r piston 36 which is also mounted in the cylinder 49 As indi ted-in dotted lines the iow r nliibf the here as is closed. The lower piston as is acted upon by the cam 42 corresponding thereto on the cam shaft 44. Under operating conditions the upper end of the piston 36 engages the piston 39 so that they operate as a unit under the action of corresponding cam 42 to produce normal opening movements of the inlet valve l2. A port 46 in the'cylinder it communicates with a groove take place. As will be evident from the construction illustrated the introduction of compressed air through the port 36 will force the pistons 30 and 36 apart. Their-relative movement is limited'by the presence of a splitring 52 located in a groove 54 in the interior wall of the bore 38, the ring 52 being engageable by the'skirt 32 upon its upward movement. It may be noted that when any longitudinal movements of the two pistons considered together, i. e., the two pistons are free to assume any positions in the cylinder 0 dictated by the spring 18 and the cam 42. The

, result accordingly is merely that of elongation of the connections between the cam Q2 and the valve I2, with the result that the valve continues to reciprocate under the action of the cam but its range of movement is lowered below its normal operating range so that it remains open at all times during the period of unloading.

The location of the split ring 52 in position is effected by the action of an annular shoulder 56 on the piston 30. The ring 52 is compressed in the space below the shoulder 58 and it and piston 30 are then entered into the bore 38 in the piston 35. As insertion takes place the ring is pushed inwardly in the bore 38 and eventually provided in the member 62. \Slidably mounted on the pin 53 is a member it provided with axially extending openings 12. A spring i l forces the member 19 downwardly and is backed up by a horseshoe-shaped member '38 which is received in a socket it in the cap 30 which is bolted to the top of the cylinder head with interposition of a gasket 82 to form a closure for the discharge chamber 84. A spring 85 received in an annular groove in the memberflfi holds downwardly a valve ring 88 to cover the openings 63 which communicate with the cylinder space above the piston. The spring 85 is efiectively weaker than the strong spring i l so that compression of air in the upper end of the cylinder will lift the valve ring 88 rather than the member 52.

The discharge valve assembly just described has various advantages. It will be evident that due to the mounting through the pin 58 the member 62 is free to adjust itself accurately to its seat. Furthermore, the entire discharge valve assembly is enclosed below the cap $9 with no projecting set screw or the like requiring special sealing against leakage of compressed air. The spring M may be so initially chosen as to the skirt 32 engages the ring 52 the compressed air between the pistons is ineifective to produce 4 exert a proper seating pressure on the'member 62 with the result that an inexperienced person cannot damage the assembly in putting it in place after its removal.

It may be noted that except in starting up the compressor the chamber 8 3 will have a pressure which is not substantially less than the pressure,

in the cylinder 5. Accordingly, even if the valve ring 88 did not function properly it is quite unlikely that the member 62 would be raised from its seat. The spring 14, of course, will be a quite strong one in any event to insure against v accidental unseating of member 52.

The operations or, the valve assemblies will already be clear from the foregoing. As stated,

unloading is effected by the maintenance of the inlet valve 12 in open position after the pressure in'th'e receiver exceeds a predetermined value, and this unloading results even though the valve it is continuously reciprocated in its lower range by the action of the cam 42.

The discharge valve ring 88, of course, opens, whenever the pressure in the cylinder exceeds by some predetermined amount, depending on the spring 96, the pressureinthe chamber M which is connected to the air receiver.

What is claimed is:

1. In a compressor including a piston reciprocating in a cylinder and an exhaust valve assembly for said cylinder, an inlet valve operatively associated with said cylinder, a seat for the inlet valve, a spring acting on said inlet valve to seat said valve, a cam shaft, a cam carried by said shaft, and'means operatively connecting said cam and said inlet valve to produce unseating motion of said inlet valve in response to rotation of said cam, said connecting means including means providing a cylinder, a pair of relatively movable pistons within thecylinder provided with interengaging means to limit separation thereof, and means for introducing compressed fluid between said pistons to separate them and so effectively to elongate said connecting means between said cam and said inlet'valve to produce unseating motion of the valve by the cam in which the valve remains unseated throughout the range of movement of the cam.

2. In a compressor of the valve-in-head type 'including a piston reciprocating in a cylinder and an exhaust valve assembly for said cylinder, an inlet valve operatively associated with said cylinder, a seat for the inlet valve, a spring acting on said inlet valve to seat said valve, a cam shaft, a cam carried by said shaft, and means operatively connecting said cam and said inlet valve to produce unseating motion of said inlet valve in response to rotation of said cam, said connecting means including a rocker arm and means providing a cylinder, a pair of relatively movable pistons within the cylinder provided with interengaging means to limit separation thereof, and means for introducing compressed fluid between said pistons to separate them and so effectively to elongate said connecting means between said cam and said inlet valve to produce unseating motion of the valve by the cam in which the valve remains unseated throughout the range of movement of the cam.

3. In a compressor including a piston reciproeating in a cylinder and an exhaust valve assembly for said cylinder, an inlet valve operatively associated with said cylinder, a seat for the inlet valve, a spring acting on said inlet valve to seat said valve, a cam shaft, a cam carried by said shaft, and means operatively connecting said 5d cam and said inlet valve to produce unseating motion of said inlet valve in response to rotation of said cam, said connecting means including means providing a cylinder, a pair of relatively movable pistons within the cylinder provided with interengaging means to limit separation thereof, said interengaging means including a skirt on one piston and a ring located in an interior groove in the other and engageable by said skirt, and means for introducing compressed fluid between said pistons to separate them and so efiectively to elongate said connecting means between said cam and said inlet valve to produce References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,649,897 Halvorsen Nov. 22, 1927 1,939,801 Wells Dec. 19, 1933 2,161,828 Lamberton June 13, 1939 2,192,538 Christensen 1 Mar. 5, 1940

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