US 2679353 A
Description (OCR text may contain errors)
y 25, 1954 R. BERNAT ET AL I 2,679,353
COMPRESSOR HAVING ROTARY SLIDE VALVE Filed Aug. 21, 1950 3 Sheets-Sheet 1 fig P 1 Wat 7M? 3 awe? M y 1954 R. BERNAT ET AL ,353
COMPRESSOR HAVING ROTARY SLIDE VALVE Filed Aug. 21, 1950 3 Sheets-Sheet 2 y 25, 1954 R. BERNAT ET AL 2,679,353
COMPRESSOR HAVING ROTARY SLIDE VALVE Filed Aug. 21, 1950 3 Sheets-Sheet 5 I 4 Q //Vl/ENTOR5 r? 000/ Ber/2 0/ Hen/'1 5 8/0 0/ A 7- raRA/Ey Patented May 25, 1954 COMPRESSOR HAVING ROTARY SLIDE VALVE Raoul Bernat and Henri Bernat, Bordeaux, France Application August 21, 1950, Serial No. 180,618
Claims priority, application France January 7, 1950 3 Claims.
The present invention relates to improvements in compressors having rotary suction slide valves allowing high speeds to be obtained.
In existing rotary slide valve compressors, the cylinders are of cast iron and the slide valve is arranged at the side. Usually, the casing of these rotary slide valves is formed integrally of cast iron with the cylinder block. On the other hand, the delivery valve is placed on the cylinder head.
The improvements forming the subject of the invention consist of some or all of the following features:
(a) First of all, the rotary suction slide valve as well as the delivery valve (which may be a lift valve or a slide valve) are arranged in the head so that the cylinder has no pipe connections nor any lateral opening.
(b) On the head itself of the compressor, there is arranged either a slide valve for suction and a magnetically attracted valve for the delivery, or two rotary slide valves, one for the suction and the other for the delivery, these two slide valves being combined with a compensating valve which is preferably magnetically actuated, or a single partition slide valve which ensures both suction and delivery, this slide valve being combined with a compensating valve as indicated above.
The function of the compensating valve is to provide a passage for the gas when, the maximum pressure having been reached in the cylinder, the delivery valve has not yet opened.
The compensating valve therefore functions during only an infinitesimal part of a second which allows the angular speed of the compressor to be increased to a substantial extent.
The head is bored to a certain depth over the same diameter as the cylinder of which it forms an extension in order that it may receive the upper part of the piston while the latter is rising.
It can, on the other hand, be formed with notches of a greater or less Width formed in the upper part of the head and corresponding to the ports of the rotary slide valves.
(d) A part of the circumferential surface of the distributing slide valve can be left free within the cylinder, the piston comprising at its upper part corresponding hollowed out portions. This feature allows the harmful space to be eliminated.
(e) The segments are disposed preferably in groups on each side of the orifices of the rotary slide valves. 7 v
(j) The cylinder or cylinders are formed of commercial steel tubes jacketed with cast iron. Such jacketing has already been effected with cast iron cylinder blocks, but in the case of the present application, it has the special advantage that the jacket corrects irregularities in the commercial steel tubes and allows an assembly to be obtained which is very robust and has a precisely dimensioned bore although being of moderate manufacturing cost.
The head comprising the rotary slide valve or slide valves is mounted by means of any appropriate joint on the said steel tube.
(9) A water jacket of sheet metal built up by welding is connected to the cylinder tube which leads both to a substantial decrease in manufacturing cost and efiicient cooling of the compressor.
Preferably, the cylinders made in this manner are set up on a base, also of sheet metal, which can be formed by joining together two U-shaped parts.
(h) The rotary slide valves are driven by an external chain from the crank shaft through an external chain preferably contained in a special casing.
By way of example, and in order that the description may be better understood, there are shown in the accompanying drawings: 2
Figure 1, a diagrammatic transverse sectional view through a cylinder head in accordance with the invention.
Figure 2, a corresponding partial view of the cylinder head alone.
Figure 3, a plan of Fig.2.
Figure 4, a view of a modified form of cylinder head comprising a rotary slide valve and a mushroom delivery valve.
Figures 5 and 6, diagrammatic views respectively in axial section and in plan, of a modified form of the cylinder head of Figure 4.
Figure 7, a vertical section through the arrangement for driving the slide valve through an external chain, and
Figure 8, a horizontal section taken on the line VlII-VIII in Figure 7.
In the embodiment shown in Figure 1, the cylinder head I has a rotary suction slide valve 3 and a delivery slide valve 4, as well as a compensating mushroom valve 7. This cylinder head is mounted on the part 2 of the cylinder.
At 5 is arranged the compensating valve made up of a ring 6 of anti-magnetic metal which forms the seat for the valve i, and the housing for the magnets 8, said magnets 8 secured to lower inner recesses at the base of the plunger l and causing the sealing and closure of the compensating mushroom valve I by exerting a suflicient magnetic attractive force on flange la to verge the anti-magnetic ring 6 into closing contact to cover the hose 9. The spring ll cooperates with the plunger [0 toguide ring 6 to its seating position along the guiding portion Eb.
Holes 9 are formed through the seat 6.
The valve 1 is flanged 1A and is formed with a guiding portion 1B. The function of the part [0 which is urged by the spring H is to ensure intimate contact between the rings and the corresponding tapered opening which forms a housing for it. The upper seat of the part I0 is guided at 12. V
The casing of the suction slide valve is shown at [3 and that of the delivery slide valve atfM.
Those casings have two notches l5 and it which open into each of the cylinders and provide a passage for the aspirated or compressed gas.
The piston P has two cut away portions i1 and I8 which conform to the shape of the part of the slide valve which projects into the cylinder.
In the accompanying drawing, the piston is shown in the position which it occupies when, during its upward stroke, the outlet port is uncovered at 19, the gas being forced into the slide valve whence it travels to the delivery conduit.
At the end of the stroke, because of the rotation l with the part of the slide valve which turns in the upper part of the cylinder. This arrangement completely eliminates the harmful space.
From that moment onwards, the piston P descends so that the port of the suction slide valve 2| comes opposite the cylinder port which fills with gas, the piston then ascends again, and the cycle. is repeated.
During the upward stroke, it can happen that the maximum pressure is reached before the outlet port opens.
At that instant, that is to say, during an extremely short period of time, the compensating valve I gives passage to the excess gas, the evacuation to delivery of which is ensured by a conduit not shown in the drawings.
The diagrammatic Figures 2 and 3 which correspond to the embodiment of Figure 1, show how the piston P, which due to its cut away portions (i and i8, mates exactly with the rotary slide valves ii and t2 and with the base of the cylinder head in which is formed the housing 43 for the compensating valve.
In the example shown in Figure 4, the cylinder head has only one slide valve 22 serving for the suction, and one double delivery valve formed of two annular valve members 25.
InFig. 4 the slide valve 22 has the same features as the corresponding slide valve of Figure 1.
The head of the piston 23 is shown at the top of its stroke. It has only one cut away portion, which mates exactly with the slide valve.
With this arrangement, it will be understood that in the compressor thus formed, the elimination of the harmful space is just about complete, because such harmful space results only from the perforations 24 through the ring and the volume of which is insignificant.
Thisnew compressor system has a great advantage relatively to compressors in which the suction valve is arranged within the piston, par- 4 ticularly in connection with the creation of very low temperatures.
In that case, the aspirated gas which is very much expanded, and at the end of the compression remains in the hollow space, is expanded before the suction valve opens, which reduces the cylinder volume accordingly.
The delivery comprises two annular valves 25. Their guiding is ensured by a ring 26 carrying a sufficient number of notches to allow free circulation of the gas.
The, movable base is formed by a ring 21 of non-magnetic metal in which are formed ports 24. The valves 25 which are controlled by the magnets 28 close those ports.
Thepart 29 urged by the spring 30, ensures contact between the ring 21 and the conical opening which forms the housing for it.
The stem of the part 29 is guided at 3|.
In Figures 1 and 4, the sheet metal cylinder is shown at 32, the cast iron jacket at 33, and the water jacket at 34.
The tube 32 andthe water jacket 34 are fixed to the part 2 by welding or any other method.
In the modification of the device of Figure 4 which is diagrammatically shown in Figures 5 and 6, there is again only one rotary slide valve 35 for suction, but two delivery valves are provided on seats 31 and 38 side by side, and one safety valve 36 is arranged in the housing. The function of that safety valve is to evacuate the liquified gas which might accidentally penetrate into the cylinder. 31 and 38 represent the seats of non-magnetic steel of the delivery valve or valves. These seats are rigidly connected to the cylinder head by screwing or any other method. 39 represents one of the conduits for the gas and M! the housing of one of the magnets.
. One of the features of the invention consists in driving the rotary slide valves such as those shown in Figures 1 and 4, by a chain drive arranged in a suitable special casing. In the embodiment of this device shown in Figures 7 and 8, a pinion M fixed to the crank shaft transmits its movement through a chain to the shaft 46 of the slide valve on which is fixed the driven pinion 41.
The device is placed in an external casing 48 of thin sheet metal in communication through one or more ports not shown with the atmosphere, and not with the gas from the compressor as in existing systems.
The rotary packings 49 as shown in section in Figs. 7 and 8 are associated with the shaft of the slide valve and allow the shafts to rotate while preventing any escape of gas.
The lubrication of the packing 49 is ensured by the conduit 50 which receives oil from the crank case.
Figure 8 shows the driving shaft 46, the driving pinion 41, and the rotary packing 49.
The gas arrives through 52 to the ports 53 which communicate alternately with each of the cylinders during each suction period.
The slide valve has two segments 54 between each of the ports.
The oil supply 5! at suitable pressure prevents any lateral escape of gas, particularly during the compression period.
The lubrication of the rotary packing is ensured by the oil supply at 5|.
It is to be noted that this arrangement of the drive of the rotary slide valves by a member such as a chain fixed in an external casing is applicable to compressors having the slide valve on the cylinder. The same applies to the arrangement described above as to the fluid tightness of the slide valves.
1. In a compressor having an inlet and outlet, a cylinder and a cylinder head, said cylinder head including a hollowed portion disposed at one side thereof and in communication with said inlet and with the bore of the cylinder, a rotary suction valve mounted for rotation in said hollowed portion and controlling the communication between the compressor inlet and said cylinder bore, that improvement comprising a piston provided with an arcuate recess at one side of the piston head to conform to the hollowed portion of the cylinder head containing said rotary suction valve, said rotary valve formed as a tubular member, a portion of said tubular member being extended into said cylinder bore in the path of said piston on the side thereof in which said hollowed portion is provided and a delivery valve mounted in said cylinder which controls the communication between said cylinder bore and said compressor outlet, said delivery valve constituted by a fixed circularly perforated valve element in said cylinder head, the perforation opening to said cylinder bore and said outlet, an annular magnetized element embedded in said valve element, and a non-magnetic movable metal ring provided with an opposing spring to seat the ring by the force of magnetic attraction.
2. A compressor as in claim 1 provided with an automatic safety valve for evacuating gas which has penetrated into the cylinder, said safety valve connected to the hollow portion of the cylinder head.
3. A compressor as in claim 1 wherein said r0- tary suction valve is provided with an extending stem and pinion, and a driving chain is fitted over said stem and pinion to drive said valve in synchronism with the operation of said compressor.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,319,787 Moran Oct. 28, 1919' 1,398,354 Wright Nov. 29, 1921 1,475,826 Hoflman Nov. 27,1923 1,513,911 Keller et a1. Nov. 4, 1924 1,516,516 Bernat Nov. 25, 1924 1,932,636 Oohtman et al Oct. 31, 1933 1,967,734 Baker July 24, 1934 2,412,725 Fitch Dec. 17, 1946 2,444,963 Taylor July 13, 1948 FOREIGN PATENTS Number Country Date 455,102 Great Britain Oct. 14, 1936