Reciprocating machine

Claim 2

Reciprocating machine comprising at least one chamber wherein is fitted a piston to compress a fluid, at least one chamber wherein is provided a piston driven by the expansion of the said fluid, these two pistons being mounted on one and the same shaft fitted in order to provide an alternating motion to each of the pistons in their respective chamber, an enclosure, provided in between the two chambers and connected to the latter by connection pipes, in which the compressed fluid is delivered and from which is withdrawn the fluid to be expanded, means for raising the temperature of the fluid in the enclosure and means for authorizing the admission and the exhaust of the fluid in each one of the chambers, the reciprocating machine being characterised in that the piston used for pressurising the fluid in the said chamber is double acting in order to provide a two stage compressor, connection pipes being provided to interconnect the two compressor stages as well as the second stage thereof to the said enclosure, the said reciprocating machine comprising a reserve of fluid compressed to a pressure exceeding that which may be reached during the running of the reciprocating machine by the fluid comprised in the pipe connection of the reciprocating machine connecting the second stage of the compressor to the said enclosure, means to connect this reserve of pressurized fluid to the pipe connection connecting the second stage of the compressor to the enclosure, means to connect this reserve of pressurized fluid to the pipe connection connecting the first stage of the compressor to the second stage of the latter as well as means to connect simultaneously with the said reserve of fluid and with the pipe connections connecting respectively the second stage to the enclosure, the first and second compressor stages, the latter means being controlled by the pressurised fluid admitted into these two pipe connections in order to allow or cut off the flow of the pressurized fluid originating from the said reserve into the pipe connection connecting the first stage of the compressor to the second stage of the latter.

Claim 3

A reciprocating machine as claimed in claim 1, characterised in that the means connecting the reserve of pressurised fluid to the pipe connection connecting the second stage of the compressor to the said enclosure comprise a normally closed, electromagnetically controlled, unidirectional valve coupled with the electric starter of the reciprocating machine, so that the valve shall be open for a set time during the running in of the motor and shall allow fluid to flow from the reserve to the connection pipe.

Claim 4

A reciprocating machine as claimed in claim 2, characterised in that the said means comprise a pressure reducer mounted downstream of the said unidirectional valve and having for its object to reduce the pressure of the fluid, originating from the reserve of fluid, to a pressure equal to that which it is possible to attain during the running of the reciprocating machine by the fluid contained in the pipe connectiOn connecting the second compressor stage to the said enclosure.

Claim 5

A reciprocating machine as claimed in claim 2, characterised in that a gauge and a stop valve are provided between the said reserve of pressurised fluid and the said unidirectional valve.

Claim 6

A reciprocating machine as claimed in claim 1, characterised in that the means assuring the communication of the reserve of compressed fluid with the pipe connection connecting the first stage of the compressor to the second stage of the latter comprise a distributor wherein are mounted differential pistons subject to the pressure ruling in the pipe connection connecting the first stage of the compressor to the second stage thereof and to the pressure ruling in the pipe connection connecting the second compressor stage to the said enclosure, this distributor being fitted to admit or cut off the flow of the fluid originating from the said fluid reserve to the pipe connection connecting the first to the second compressor stage when the pressures ruling in the said two pipe connections vary one with reference to the other.

Claim 7

A reciprocating machine as claimed in claim 5, characterised in that means are provided to cooperate with the piston of the said distributor subject to the pressure ruling in the pipe connection connecting the first to the second compressor stage in order to permit modifying the ratio existing between a set pressure ruling in such pipe connection and the corresponding pressure ruling in the pipe connection connecting the second compressor stage to the said enclosure, particularly in order to allow for the wear of the compressor.

Claim 8

A reciprocating machine as claimed in claim 6, characterised in that the means cooperating with the said piston comprise a spring the adjustable strain of which may be changed by means of a screw.

Claim 9

A reciprocating machine as claimed in claim 6, characterised in that the said means comprise a push rod resting on an element cooperating with the piston of the distributor subject to the pressure ruling in the pipe connection connecting the first to the second compressor stage and controlled by an aneroid case, the push rod being fitted to increase its pressure, because of the action of the aneroid case on the said piston by means of the said element when the atmospheric pressure drops.

Claim 10

A reciprocating machine as claimed in claim 5, characterised in that the means connecting the reserve of pressurised fluid to the pipe connection connecting the first and second compressor stages comprise a unidirectional valve, controlled by the said distributor and connected to the reserve of pressurised fluid, downstream of the closing valve and upstream of the unidirectional valve and of the pipe connection connecting the first to the second stage of the compressor, such valve being fitted to permit the flow of the fluid originating from the reserve to the latter pipe connection when the equilibrium between the pressures ruling in the said two pipe connections, determined by the compressor characteristics is broken by a rise of the pressure ruling in the pipe connection connecting the second compressor stage to the enclosure.

Claim 11

A reciprocating machine as claimed in claim 9, characterized in that a microvalve is inserted between the distributor and the said unidirectional valve in order to reduce the strain of the latter when controlling the said unidirectional valve, the microvalve being connected to the pipe connection connecting the unidirectional valve to the reserve of pressurised fluid, a pressure reducing valve being provided on this branch and connected to the unidirectional valve, the pistons of the latter being fitted in such a manner that the low pressure fluid, acting on the opening of the microvalve, by the action of the distributor may overcome the pressure of the reserve fluid and ensure the opening of the unidirectional valve in order to permit the flow of the reserve fluid from the reserve to the pipe connection connecting the first to the second comPressor stage.

Claim 12

A reciprocating machine as claimed in claim 5, characterised in that the distributor is associated with an adjustable sequential valve mounted downstream of the distributor with reference to the pipe connection connecting the second compressor stage to the said enclosure in order to prevent the differential pistons continuously moving within the distributor to permit and stop the flow of the fluid originating from reserve to the pipe connection connecting the two compressor stages, when the pressures ruling in the said two pipe connections are within their equilibrium range determined by the compressor characteristics, such sequential valve being mounted inbetween the distributor chamber connected to the pipe connecting which connects the second compressor stage to the said enclosure and such pipe connection.

Claim 13

A reciprocating machine as claimed in claim 5, characterised in that in the pipe connection connecting the two stages of the compressor, there is provided between the said unidirectional valve and the compressor, a second unidirectional valve fitted to cut off the flow of the fluid between the latter and the compressor when the pressure ruling between such two unidirectional valves as well as between such second unidirectional valve and the compressor exceeds a set pressure.

Claim 14

A reciprocating machine as claimed in claim 5, characterised in that the said distributor comprises a cylinder wherein are assembled two pistons able to move one with reference to the other, a first piston being subjected to the action of the fluid within the pipe connection connecting the first to the second compressor stage, while the second piston is subjected to the action of the fluid within the pipe connection connecting the second compressor stage to the said enclosure, the second piston being provided on the one hand with a peripherical recess providing a leak-proof chamber in communication through an opening provided in the cylinder with the pipe connection connecting the second compressor stage to the said enclosure and, on the other hand, with an axial recess communicating with the said chamber and wherein is housed an element of the first piston having a cross-section corresponding to that of the recess and provided with tightness means, the first piston being provided opposite the said element with a central stem providing the control stem of the distributor permitting or preventing the flow of the fluid from the reserve to the pipe connection connecting the first to the second compressor stage, the two pistons being further fitted in order to determine in the said cylinder four chambers isolated in a leak-proof manner from one another and laid out in the following manner, a first chamber comprised inbetween the actual first piston and the cylinder walls and partly surrounding the said control stem, this first chamber communicating, through an opening provided in the cylinder, with the pipe connection connecting the first to the second compressor stage, a second chamber comprised inbetween the first and the second piston and partially surrounding the said first piston element, such second chamber being connected to atmosphere through an opening provided in the cylinder, a third chamber provided by the peripheral recess produced in the second piston and communicating with the pipe connection connecting the second stage of the compressor to the enclosure, a fourth chamber communicating with atmosphere through an opening provided in the cylinder, wherein is fitted a spring supported by the second piston, the portion of the second piston comprised between the said second and third chambers being provided with studs of decreasing lengths and their axes running parallel to that of the piston around which the studs are uniformly laid out inside channels wherein the studs are able to slide in a leak-proof manner, each of these studs comprising a peripherical stop positioned inside the third chamber and extending through the second chamber so as to be able to rest on the first piston, stops being provided for the first and the second piston in the first and the second chamber respectively, the said spring being selected in such a manner that it forces the second piston against its stop for the minimum set pressure allowed in the first chamber and shall experience maximum compression for the maximum determined pressure allowed in such first chamber, the stroke of the spring being substantially equal to the difference in lengths of the longest and the shortest of the said studs.

Claim 15

A reciprocating machine as claimed in claim 13, characterised in that the strain of the said spring is adjustable, an adjustable tension spring being also provided to cooperate with the first piston.

Claim 16

A reciprocating machine as claimed in claim 1, characterised in that the pipe connection connecting the second compressor stage and the said enclosure communicates with a duct connecting the reserve of pressurised fluid to a electromagnetically controlled unidirectional valve, upstream of the latter with reference to the fluid reserve in order to refill the latter with pressurised fluid.

Claim 17

A reciprocating machine as claimed in claim 15, characterised in that a unidirectional valve is provided in the duct connecting the said pipe connection and the duct connecting the reserve and the said valve, such valve normally closed being fitted to open at a set pressure ruling inside the pipe connection connecting the second compressor stage and the enclosure, such set pressure being slightly below the pressure ruling in the latter pipe connection during normal running of the reciprocating machine, in order to permit the flow of the pressurised fluid originating from the said pipe connection to the fluid reserve, a non return check-valve being provided between the valve and the reserve and fitted in such a manner that even when the valve is open, pressurised fluid originating from the pipe connection is only able to enter the said reserve when the pressure of the fluid contained in the latter is below the pressure ruling in the pipe connection connecting the second compressor stage to the enclosure.

Claim 18

A reciprocating machine as claimed in claim 16, characterised in that a throttle is provided in the said duct in order to throttle the flow of the fluid to the reserve when the valve and the nonreturn check valve permit such flow.

Claim 19

A reciprocating machine as claimed in claim 1, characterised in that a by-pass is provided in the pipe connection connecting the compressor to the enclosure upstream of the latter, directing fluid originating from the compressor to the means allowing the admission of the fluid to the chamber wherein the expansion of the fluid takes place in order to cool the said means.

Claim 20

A reciprocating machine as claimed in claim 1, characterised in that a heat exchanger is provided in the pipe connection connecting the compressor to the said enclosure, this heat exchanger, used for preheating the fluid flowing from the compressor to the enclosure, being connected to the exhaust of the chamber wherein the expansion of the fluid takes place.

Claim 21

A reciprocating machine as claimed in claim 19, characterised in that it comprises means allowing to balance, during variations of the speed of the reciprocating machine, the pressures ruling in the said enclosure and in the pipe connection connecting the second compressor stage to the said enclosure.

Claim 22

A reciprocating machine as claimed in claim 20, characterised in that the means permitting to balance the said pressures comprise a cylinder in which is fitted a double acting piston detemining two chambers in the said cylinder, a valve provided with a double acting plunger determining four chambers inside the valve along th axis of the plunger, a duct assuring the communication of the said enclosure with a first chamber of the cylinder and a first terminal chamber of the valve, ducts being provided to assure the communication of the second end chamber of the valve with the duct connecting the Second compressor stage to the enclosure upstream of the heat exchanger, the second cylinder chamber with the internal chamber of the valve nearest the second end chamber of the valve and the second chamber of cylinder with the internal chamber of the valve nearest the first end chamber of the said valve, such normally closed valve being fitted so as to open when the pressure rises sharply in the enclosure in order to connect the two internal chambers of the valve.

Claim 23

A reciprocating machine as claimed in claim 21, characterised in that a non-return check valve and a throttle are provided in the duct connecting the second chamber of the cylinder and the internal chamber of the valve nearest the first terminal chamber of the latter in order to adjust the flow of the fluid from the valve to the cylinder.

Claim 24

A reciprocating machine as claimed in claim 1, characterised in that it is mounted in a closed circuit so as to provide a so-called ''''hot-air'''' reciprocating machine, the exhaust of the chamber wherein the fluid expands being connected to the entry of the first compressor stage, a cooler being mounted in the duct connecting the said exhaust to the compressor.

Claim 25

A reciprocating machine as claimed in claim 1, characterised in that the enclosure in which the temperature of compressed fluid is increased comprises a safety valve which is regulated so as to open at a determined pressure higher than the normal working pressure of the motor and lower than the breaking pressure of the enclosure, said valve being either open to atmosphere or connected to motor exhaust pipe.

Claim 26

A reciprocating machine as claimed in claim 1, characterised in that it comprises means to vary for a given rotation speed of the motor the admission time in the chamber where the fluid is expanded, in terms of the resisting torque.

Claim 27

A reciprocating machine as claimed in claim 1, characterised in that it comprises means to vary for a given rotation speed of the motor, the exhaust time in the chamber where the fluid is expanded in terms of the resisting torque.

Claim 28

A reciprocating machine as claimed in claim 26, characterised in that it comprises means to simultaneously vary the admission time and the exhaust time in the chamber where the fluid is expanded for a given rotation speed of the motor in terms of the resisting torque, said means being arranged so that when the admission time is increased, the exhaust time is reduced and vice versa.

Claim 29

A reciprocating machine as claimed in claim 25, characterised in that said means allowing to vary either the admission time or the exhaust time in the chamber where the fluid is expanded are formed by two cams mounted on a shaft rotated by the motor and actuating through a moving equipment of Caprotti type, the admission and exhaust valves, said moving equipment comprising a rocker-lever pivoting around a fixed axis and the ends of which each support a follower cooperating with one of said cams, one of said cams being locked on said shaft while the other cam is free mounted on the latter, a sliding means being provided on the shaft to control the angular movement of the moving cam with respect to the cam locked on the shaft, the latter having a threaded portion forming an endless screw with very elongated pitch cooperating with the sliding means and causing when the latter longitudinally moves in parallel to the shaft axis, the rotation of the moving cam around the latter, by means of at least one rod parallel to the axis of said shaft, said rod being fixed to the moving cam and being able to freely slide in an aperture provided in the sliding means, movements of the latter being controlled by a rod system connected to the motor accelerator.

Claim 30

A reciprocating machine as claimed in claim 27, characterised in that said means allowing to simultaneously vary the admission time and exhaust time comprise two sets of two cams mounted on said shaft which is driven by the motor, each set controlling through a moving equipment one of the Admission or exhaust valves, each set of cams comprising a cam locked on said shaft and a cam freely mounted on the latter, the moving cam of each of cam sets being controlled by a sliding means, said sliding means cooperating, to cause the rotation of moving cams, with said threaded shaft portion forming an endless screw with very elongated pitch, both sliding means being simultaneously controlled by a rod system connected to the motor accelerator.