US1878326A - Air compressor of the multicylinder reciprocating type - Google Patents

Description

se t; 20; 1932.

H. R. RICARDO AIR COMPRESSOR OF THE MULTICYLINDER RECiI-ROCATING TYPE 2 Sheets-Sheet 1 Filed April 13, 1932.

Sept. 20, 1932. H. R. RICARDO 1,878,325

I AIR COMPRESSOR OF THE MULTICYLIND ER RECIPROCATING TYPE Filed April 13, 1932 2 Sheets-Sheet 2 Patented Se t '20, 1932 UNITED STA TESI-PATEN HARRY Rnnrrr RICARDO, on tonn'on, ENGLAND AIR oonrrnnsson on THE monrrovnrnnnn nnclrnoonrme TYPE Application filed April 13, 1932, Serial No. 605,099, and in GreatiBritain Ap rll 28, 1931.

This invention relates .to of the multi-cylinder reciprocating type in which inlet and delivery ports in each cylin-,

- der are controlled .by one or more sleeve valves, and has for its object to provide improved means for unloading such compres- To this end in an air compressor of the above type according to the present invention, there is combined with a cylinder group comprising two or more cylinders the movements of the istons in which have such phase-relations ip that the sum of the volumes of'the compression spaces of such cylinders remains constant or only varies slightlye throughout the cycle of operations, unloadin mechanism comprising one or more va ves (hereinafter termed unloadingvalves) whereby the workin spaces of the cylinders in such group can e brought into direct communication with one another, and a nonreturn valve in the delivery passage leading from each cylinder or in a common delivery passage leadmgfrom two or more cyllnders' constituting the group or part of the group.

' It will thus be seen that when the unloading and forwards between these cylinders but valve or valves are opened to bring-the compression spaces of the cylinders of a group into communication, air will be caused by the pistons in such cylinders to flow backwards no air will be delivered,-whi1e the non-return valve or valves will close the delivery passage flow,the non-'return valve or valves will close or assages from the cylinders toprevent bac ow of air'into the cylinders ,from the delivery passage. 1 a

' Preferably the action -ofthe non-return valve-or valves is such that whereas such,

.valve or valves will be maintained continu ously 'open'during normal operatron of the compressor n spite of .cyclic variations in automatically when delivery of air by the compressor c e'ases,'for example when the unloadlng valves are opened. "Thus repeated openingand closing of the non-return valve or valves during normal operation of the compressor is'prevented. 4 e unloading valves may be of various forms butconveniently the unloading mech air compressors livery passages from the cylinders which lie on the side of the non-return valve or valves adjacent to the cylinders.

The means for opening the unloading valves may vary but in one arrangement these valves are adapted to be opened by one or more pistons each disposed within a cylinder and adapted to be acted upon by fluid pressure derived from thereceiver or the like to which the compressor delivers air or gas. A single piston may control all the unloading valves for the cylinders constituting each group, or a separate piston may act on each valve, for example in the case of oppet valves by a direct connection between t evalve stem and piston. In anycase a relay valve may so be provided which normally admits atmospermit flow of air under pressure thereto from the receiver so as to open the unloading valves when the pressure in the receiver reaches or exceeds a predetermined value whereby the unloading valves are automatically opened whenever the ressure inthe receiver exceeds a redeter'mmed value and flare automaticallyc osed when this pressure drops belowsllch predetermined value. Alternatively the arrangementmay be such that the unloading valves are automatically opened when thepressu're in the receiver exceeds one predetermined value but vare not 1.

sleeve valve E and these parts.

automatically closed again until the pressure has dropped below'some other and lower predetermined value, thus tending toprevent Figure 1 is a sectional side elevation of a two-cylinder compressor accordingto this invention, j r

Figure 2 is aplan partly in section of the engine shown in Figure 1, and

FigureB is a section on the line 33 of Figure 2.

In the construction illustrated the compressor comprises a crank case A on which is mounted a cylinder block B containing two cylinders having cylinder liners B and surrounded by a water jacket B having an inlet passage B and an outletpassage B.

Formed in the wall of each cylinder liner B is a series of slot-like inlet ports C communicating with an induction belt C the part C otwhich lying between the cylinders iscomlnon to both cylinders. Extending into the upper end ofeach cylinder is a plug-like cylinder head D and an annular space D is 16a between .the lower end of each plug-like cylinder head and the. upper end of its associated liner 13 such space constituting the.

delivery port from the cylinder.

Disposed within each cylinder liner is a sleeve valveE the upper end of which hes around and is closed by the plug-like cylinder head 1), packing; rings. E being provided respectively in grooves in the cylinder head D and in the upper end of the cylinder liner B to prevent escape of fluid between the Each sleeve valve is provided on the one hand with a series of slot-like inlet ports E adapted to cooperate with the slot-like inlet ports C in the cylinder liner surrounding it and on the other hand with a ring of delivery ports E adapted to cooperate with the delivery port D A piston F coupled by a connecting rod F to a crank shaft F mounted in bearings in the crank case A reciprocates directly within each sleeve, the cranks to which the two pistons F are coupled being angularly displaced by 180. A combined oscillating and reciprocating movement is imparted .to each sleeve by mechanism, known in itself,-com

E is such that the ports E come into communication with the ports C and the ports E come into communication with the delivery port D twice during each cycle of each sleeve valve E. Thus, assuming a valve E to be in the position shown for the valve in the lefthand cylinder of Figure 1, thatis to say the position in which the valve has just completed one of the two portions of its movement which are mainly'oscillatory and is about to begin that portion of its movement which is mainly reciprocating in an upward direction, this upward movement will first carry the ports E into comunication with the port D so that delivery can take place through the ports E and D during the last part of the travel of the piston in the upward direction. At the end of the upward movement of the piston,

the continued upward movement of the sleeve will carry the ports E above the port D The movement of the sleeve now begins to be mainly oscillatory and this movement will cause the ports E to be moved across the upper ends of the ports G as the piston descends so that air can be drawn in through the ports E C. At or towards the end of the downward movement of the piston the ports E will have been carried completely across and out of register with the ports C and the movement of the sleeve will begin to be mainly reciprocating in a downward direction so that as the piston again ascends the ports E will move downwards into registerwith the port D during the end portion of the upward stroke of the piston and will again be carried out of register with these ports when the piston reaches its upper dead centre. The. movement of the sleeve will now be mainly oscillatory again and will cause the portsE to -move across the lower ends of the ports C duringthe subsequent suction stroke of the through the ports E and C. It will therefore be seen that although the valve E is only operative at half crankshaft speed yet the delivery ports and suction ports are each opened twice during each valve cycle so as to connect the working chamber of each cylinder to the induction belt during each suction and to the delivery .chamber during each delivery stroke.

The delivery ports D communicate with annular delivery chambers H and these two chambers H communicate with one another and with a common delivery passage H as shown in Figure 2. Formed in each plug-like cylinder head D is a port D whichis normally piston so that'air can again be drawn in.

with a delivery pipe H through a non-return valve H- of the poppet type which is acted upon by a light spring H tending to maintain it always closed and is controlled by a dashpot,device-comprisi ng a piston'H at one end of the valve stem having a small leaka e passage indicated at H and disposed'within a cylinder H filled with oil. The arrange ment is such'that the valve H will be opened automatically by the pressure of air-delivered .by the compressor and the dash-pot device H, H will prevent this valve closing under;

H the action of its spring during cyclic varia- "each valveD is a collar J from which extend trunnions J which are connected by llnks J to a pivot pin J which passes through an intermediate point inalever K .one end of which is pivoted to a bracket K on the cylinder head, while its other end bears on the upper end of a piston L which is common to both levers K.

The piston L is arranged within a cylinder L having an opening, 2 at its lower end, a

' light helical spring L acting on the lower end of the piston and serving always to maintain its upper end in contact with the. ends of the leversK. The cylinder L is located within a chamber'M partially filled with oil so that I reduced diameter so as to the opening L is always below oil level and this. chamber communicates through a passage M with a valve whereby the chamber. M can be brought into communication either with the atmosphere or with the pressure in the delivery pipe H from the compressor.

This valve comprises a cylinder N the'lower end of which is connected by a pipe N to the delivery pipe H Arranged within the cylv lnder'N is a piston-N hav1ng afportion N of provide an annular chamber N which communicates through a assage N in the piston with the atmosp ere and, when the valve is in the position shown in Figure 3 also communicates with the passage M sothat the chamber M and hence the underside of the piston L is subject only to atmospheric pressure. The piston N carries a weight N at its upper end which normally tends to maintain it in the position indicated in Figure 3, but when the pressure in the delivery pipe H exceeds a predetermined value, this pressure will raise the piston N so that 1ts lower end uncovers the passage M whereupon air under pressure from the delivery pipe N will be delivered to the chamber M' so that this pressure will act on the underside of the piston L and thus raise this piston and thereby act through the levers K to lift both the valves D The operation of the compressor is asfollows. During normal operation air will be drawn during each suction stroke of each piS- ton through the inlet orts E and C lIl' its. associated cylinder, an will be delivered during each delivery stroke through the ports E and D into the-chambers H and thence through the common delivery passage H and the valve H into-the delivery pipe H If, now, the pressure in the pipe H exceeds a predetermined value, this pressure will act through the pipe N on the piston valve N 2 so as to raise this piston valve and thereby admit air under pressure through the passage M to the chamber M. This air will act through the opening L .on the piston L so as I 4 to raise this piston and thereby act through the levers K to open both the unloading valves 1) against the action of their sprlngs 13*. Thus the compression spaces of the two cylinders will be brought, through the passa es H and the common delivery passage into communication with one another and since the cranks associated with the two p1stons F are angularly displaced by 180, it will be seen that with the two valves D open, air will simply be caused to travel backwards andforwards between the compression spaces of the cylinders and no air will be dellvered through the valve H andpipe H The valve H will therefore close under the action of its spring so as to prevent back flow of air from the delivery p1pe H into the common delivery passage H If the air pressure in the delivery pipe H drops, owing for example to the consumptlon of air, the piston valve N :will again move into the position indicated. in Figure 3 so as to bring the chamber M- again into communication with the atmosphere. The piston ,L will now descend under the action of the levers K due to the force of the valve springs 'D whereupon delivery of air by the compressorwill again begin, the valve H will be opened and the compressor will continue 7 in operation until the pressure in the pipe H again exceeds the predetermined valuewhen v the compressor will again automatically be unloaded as described above.

It is to beunderstood that although. in 1 the construction illustrated means are provided for unloading, the compressor automatically when the compression pressurein the delivery pipe exceeds a predetermined value, the invention 'isnot limited to such an,

arrangement but that unloading mechanism accor ing-to this invention may begoperated either automatically or at will. Further, the

invention may be applied to multi-cylinder reciprocating air. compressors having more than two cyllnders and 1n such cases the un.

loading may beetfected-bybrin ing the com- .125

pression spaces of all the cylin ersofflthe air compressor intocommunlcatlon or by brlnging thecompression' spaces-of two ormor'e groups of cylinders into communication, the

groups being selected so that the sum of the volumes of the compression spaces of the cyl:

inders in each group remains substantially constant throughout the operation of the com pressor.

' What I claim as my invention and desire to secure by Letters Patent isout the cycle of operations, one or more valves whereby the working spaces of the cylinders in each group can be brought into continuous direct communication with one another, and a non-return valve in thedelivery passing leading from each cylinder.

2. A compressor for gas of the multi-cylinder reciprocating type including in combination at least two cylinders having inlet and outlet ports therein, sleeve valves controlling these ports, pistons in the cylinders the movements of which have such phase-relationship that the sum of the-volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders can be brought into continuous direct communication with one another, and a non-return valve in the delivery passage leading from each cylinder.

3. A compressor for gas of the multi-cylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports therein, each group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pistons in the cylinders, the movements of the pistons in each group havingsuch phase-relationship that the sum of the volumes of the compression spaces of the cylinders in each group re.-

out the cycle of operations, one or more valves whereby the working spaces of the cylinders in each group can be brought into continuous directcommunication, with one another, and

open during normal operation of the com-- der reciprocating type including in combination at least two cylinders havlng inlet and a a non-return valve in the delivery passage leading from each cylinder, the non-return valve being so constructed and arranged that whereas it will be maintained continuously pressor in spite of cyclic flow variations it a will close automatically when delivery of fluid ceases.

4. A compressor for gas of the multi-cylinoutlet ports therein, sleeve valves controlling these ports, pistons in the cylinders the movements of which have such phase-relationship that the sum of the volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders can be brought into continuous direct communication with one another, and a non-return valve 'in the delivery passage leading from each cylinder, the non-return valve being so constructed and arranged that whereas it will be maintained continuously open during normal operation of the compressor in spite of cyclic flow variations it will close automatically when delivery of fluid ceases.

5. A compressor for gas of the multi-cylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports therein, each group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pistons in the cylinders, the movements of the pistons in each group having such phase-relationship that the sum of the volumes of the compression spaces of the cylinders in each group remains within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders in each group can be brought into continuous direct communication with one another, a non-return valve in the delivery passage leading from'each cylinder, and a dashpot so controlling the non-return valve that .whereas it will be maintained continuously open during normal operation of the compressor in out the cycle of operations, one or more valves mains within small limits the same through-c whereby the working spaces of the cylinders can be brought into continuous direct communication with. one another, anon-return valve in the delivery passage leading from each cylinder, and a dashpot so controlling the non-return valve that whereas it will be bination at least one group of cylinders having inlet and outlet ports therein, each group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pistons in the cylinders, the movements of the pistons in eachv group having such phase-relagroup remains within small limits the same throughout the cycle of operations, a springcontrolled poppet valve in each cylinder headadapted to move when opening in a direction away from the cylinder, the poppet valves in the heads of the cylinders consti tuting each group communicating with a common passage through which, when these poppet valves are opened, the working chambers of all the cylinders in each group are brought into direct communication, a delivery passage leading from the common passage and a non-' chamber, and a non-return valve 1n each of return valve in this delivery passage.

8. A compressor for gas of the multi-cylinder reciprocating type including in combination at least two cylinders having inlet and outlet ports therein',.sleeve valves controlling these ports, pistons inthe cylinders the movements of which havev such phase-relationship that the sum of the volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, a spring-controlled poppetvalve in each cylinder head adapted to move when opening in a direction away from the cylinder, poppet valves in the heads of the two cylinders com municating with a common passage through which, when the poppet valves are open, the working chambers of the two cylinders are brought into direct communication, a delivery passage leading from the common passageand a non-return valve in the delivery passage.

' 9. A compressor for gas of the multi-cylinder reciprocating type including in combination at least two cylinders having inlet and outlet ports therein, Sleeve valves controlling these ports, pistons in the cylinders the movements of whichha've such phase-relationship that the sum of the volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, a spring-controlled poppetvalve in each cylinder head adapted to move when opening in a direction away from the c linder, the poppet valves in the heads o the cylinders communicating with a common passage through which, when the poppet valves are open, the working chambers of the two cylinders are brought into direct communication, a delivery passage leading from the common passage and a non-return valve in the delivery passage, and-*a dashpot control-. 1n

the non-return valve so that whereas it 'wil be maintained continuously open durmg normal operation of the compressor in spite of cyclic flow variations it will close automatically when delivery of fluid ceases.

10. A compressor for gas of the multi-cylinderreciprocating type including in combinationat least one group of cylinders having ports communicating with one another through a common delivery chamber, each v cylinder group including at least twocylinders, sleeve valves controllin the inlet and outlet ports, pistons in the cy inders in each;

group the movements of which have such phase-relationship that the sum of the volumes of the compression'spaces of the cylinders in each group remains within small limcation with the common delivery chamber, at 5 least one delivery passage'leadingfrom this the said delivery passages.

11. A compressor for gas of'the multicylinder reciprocating type including in combination two cylinders having inlet ports and. outlet Ports which communicate with a common de 1 very chamber, sleeve valves .con-

trolling the inlet and outlet ports, pistons in the cyllnders the movem ntsjof which have such phase-relationship t at-the sum of the volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders can be brought into continuous direct communication with the common de livery chamber, a delivery passage leading from such chamber, and a non-return valve in the delivery passage.

12. A compressor for gas of the 'multi-w cylinder reciprocating type including in combination two cylinders having inlet 'ports and outlet ports which communicate with" a common delivery. chamber, sleeve valves controlling the inlet and outlet ports, pistons in the cylinders the movements of which have such phase-relationship that the sum of the cylinders remains within small limits the same throughout the c cle of operations, one or more valves where y the working spaces of the cylinders can be brought into continuous direct communication with the common delivery chamber, a delivery passage leading from such chamber, a non-return valve in the delivery passage, and a dashpot that whereas this valve will be maintained continuously open during normal operation of the compressor in spite of cyclic flOW'VfiIlations it will close automatically when delivery of fluid ceases.

volumes of the compression spaces'of the 1 device controlling the non-return valve so 13. A compressor-for the m'ulti-cylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports therein, the group including at least two cylinders, sleeve valves controlling the inlet, and outlet ports, pistons in the cylinders in each groupthe moveinlet ports and outlet ports therein, the outlet p5 ments of which have such phase-relationship sion spaces of the cylinders in each group remains'within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders in each group can be brought into continuous direct communication with one another, a non-return valve in the delivery passage leading from each cylinder, and

' means for automatically opening the unloading valves for bringing the spaces of the cylinders in each group 'into continuous direct communication comprising at least one control cylinder, a piston in each control cyl-' inder, an operative connection between this piston and an unloading valve and means for delivering to each cylinder fluid under pressure from the receiver to, which the compressor delivers gas.

14. A compressor for gas of the multicylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports thereln, each group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pistons .in the cylinders in each group the movements of which have such phase-relationship' that the sum of the volumes of the compression spaces of the cylinders in each group remains within small limits the same throughout the cycle ofoperations, a springcontrolled poppet valve in each cylinder head adapted to move when opening in a direction away from the cylinder, the poppet valves in the heads of the cylinders constituting each group communicating with a common passage through which, when these poppet valves are opened, the working chambers of all the cylinders in each group are brought into direct communication, a delivery passage leading from each common passage, a non-return valve in the delivery passage and means for opening the poppet valves com-- rising at least one control cylinder, a piston I in each control cylinder an operative convalve, and means for delivering fluid 'under pressure to each control cylinder from the nection between this piston and a poppet receiver to which the compressor delivers gas.

15. A compressor for gas of the multicylinder reciprocating type including in combination at least two c linders having inlet and outlet portstherein, sleeve valves controlling these ports, pistons in the cylinders the movements ofwhich have such phaserelationship that the sum of the volumes of the compression spaces of the cylinders remains within 1 small limits the same throughout the cycle of operations, aspringcontrolled poppet valve in each cylinder head adapted to move when opening in a direction away from the cylinder, the ports controlled by the poppet valves in the heads of the two cylinders communicating with a common passage through which, when the bers of the two cylinders are brought into direct communication, a delivery passage leading from the common passage a nonreturn valve in the delivery passage, and means for openingthe poppet valves comprising at least one control cylinder, a piston in each control-cylinder, an operative connection between this piston and a poppet valve and means for delivering fluid under pressure to each control cylinder from the receiver to which the compressor delivers gas.

16. A compressor'for gas of the multicylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports therein, the group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pistons in the cylinders in each group the movements of which have such phase-relationship that the sum of the volumes of the compression spaces of the cylinders .in each group remains within small limits the same throughout the cycle of operations, one or more valves whereby the working spaces of the cylinders in each group can be brought into continuous direct communication with one another, a non-return valve in the delivery passage leading from each cylinder, means for automatically opening the unloading valves for'b-ringing the compression spaces of the cylinders in each group into continuous direct communication comprising at least one control cylinder, apiston ineach control .cylinder, and an operative connection between this piston and an. unloading valve, and means for delivering to each control cylinder fluid under pressure from the receiver to which the compressor delivers gas comprising a valve which normally admits atmospheric pressure only to the said control cylinder but when the receiver reaches a predetermmed value acts automatically to cut oflt' the control cylinder from atmospheric pressure and permit flow of as thereto from the receiver.

1 A compressor for gas of vthe multi cylinder reciprocating type including in combination at least one group of cylinders having inlet and outlet ports therein, each group including at least two cylinders, sleeve valves controlling the inlet and outlet ports, pisressure in the tons in the cylinders in each group the movements ofwhich have such phase-relationship that the sum of the volumes of the compression spaces of the cylinders in each group v remains within small limits the same throughout the cycle of operations, a spring-controlled poppet valve n each cylinder head adapted to move when opening in a direction away from the cylinder, the poppet valves in theheads of the cylinders constituting eachgroup communicating with a common passage through which, when. these poppet valves are opened, the Working chambers of all the cylinders in each group are brought into direct communication, a delivery pas. sage leading from such common passage '3.

non-return valvein the delivery passage,

means for opening the poppet valves comprising at least one control cylinder, a piston in each control cylinder, an operative connection between this piston and a poppet valve and means for delivering fluid under pressure to each control cylinder from the receiver to which the compressor delivers gas, and means for controlling the flow of fluid under pressure from the receiver in each control cylinder, comprising a valve which normally admits atmospheric pressure only to the said control cylinder but when the pressure in the receiver reaches a prede- *termined value acts automatically to cut off the control cylinder from atmospheric p-ressure and permit flow of gas thereto from the recelver. i Y

' 18. A compressor for gas of the multi-cylinder reciprocating type including in com bina-tion at least two cylinders having inlet and outlet ports therein, sleeve valves controlling these ports, pistons in the cylinders the movements of which have such phaserelationship that the sum of the volumes of the compression spaces of the cylinders remains within small limits the same throughout the cycle of operations, a spring-controlled poppet valve in each cylinder head adapted to move when opening in a direction away from the cylmder, the poppet valves in the heads of the two cylinders communicating with a common passage through which, when the poppet valves are opened, the working chambers ofthe two cylinders 40 are brought into direct communication, a delivery passage leading from the common passage a non-return valve inthe delivery passage, means for opening the poppet valves comprising at least one control cylinder, a piston in each control cylinder and operative connection between this piston and a po pet valve and means for delivering flllld' under pressure to each control cylinder from the receiver to which the compressor deliv- 6 ers gas, and means for controlling the flow of fluid under pressure from the receiver in each control cylinder, comprising a valve which normally admits atmospheric pressure only to the said control cylinder but when the pressure in the receiver reaches a predetermined value acts automatically to cut ofi the control cylinder from atmospheric pressure and permit flow of gas thereto from the receiver.

I m In testimony whereof I have signed my name to this specification. HARRY RALPH RICARDO.

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