EP3523537A1

EP3523537A1 - Semi-hermetic coolant compressor

Info

Publication number: EP3523537A1
Application number: EP16778057.6A
Authority: EP
Inventors: Rainer GROSSE-KRACHT; Hermann Renz; Eduardo Martin; Jens MANNEWITZ
Original assignee: Bitzer Kuehlmaschinenbau GmbH and Co KG
Current assignee: Bitzer Kuehlmaschinenbau GmbH and Co KG
Priority date: 2016-10-07
Filing date: 2016-10-07
Publication date: 2019-08-14
Anticipated expiration: 2036-10-07
Also published as: AU2016425930A1; BR112019006964A2; EP3523537B1; EP4276311A2; ES2981313T3; CN109715945A; RU2019112862A; CN113294311A; CN113294311B; WO2018065071A1; EP4276311A3; AU2016425930B2; DK3523537T3; RU2745598C2; RU2019112862A3; CN109715945B; US20190234392A1

Abstract

The invention relates to a semi-hermetic coolant compressor, comprising a reciprocating compressor, an electric motor, a complete housing which has a motor housing section for the electric motor and a compressor housing section for the reciprocating compressor, a suction-side coolant path which leads from a suction connection on the complete housing to an inlet chamber of the reciprocating compressor, and a pressure-side coolant path which leads from an outlet chamber of the reciprocating compressor to a pressure connection on the complete housing. The aim of the invention is to improve such a coolant compressor such that the coolant compressor functions more efficiently. This is achieved in that the electric motor is designed as a synchronous motor, the rotor of which is equipped with permanent magnets for the synchronous operation of the electric motor and a squirrel cage for starting up the electric motor in the asynchronous operation.

Description

HALF-HERMETIC REFRIGERANT COMPRESSOR

The invention relates to a semi-hermetic refrigerant compressor,

comprising a reciprocating compressor and an electric motor, an overall housing having a motor housing portion for the electric motor and a compressor housing portion for the reciprocating compressor, one leading from a suction port on the overall housing to an inlet chamber of the reciprocating compressor suction side refrigerant path and one of an outlet chamber of the reciprocating compressor to a pressure port on the overall housing leading pressure-side refrigerant path, wherein in the

Compressor housing portion at least one cylinder of the reciprocating compressor is provided, which has a movable in a cylinder housing in the compressor housing section piston, a cylinder bore final valve plate and a valve plate cross and forming part of the compressor housing section cylinder head.

Such semi-hermetic refrigerant compressors are known from the prior art.

A semi-hermetic refrigerant compressor has the outer housing as the overall housing, wherein in particular the electric motor is arranged in the refrigerant atmosphere. A semi-hermetic refrigerant compressor is not provided with a reciprocating compressor and the electric motor together completely enclosing the outer casing, but the at least one cylinder housing forming compressor housing is itself the outer casing.

These have the problem of operating them more energy efficiently. This object is achieved in a semi-hermetic refrigerant compressor of the type described above according to the invention that the

Electric motor is designed as a synchronous motor, are arranged in the rotor permanent magnets for the synchronous operation of the electric motor and a short-circuit cage for the start of the electric motor in the asynchronous operation.

The advantage of the solution according to the invention is the fact that such an electric motor for driving a semi-hermetic refrigerant compressor higher energy efficiency, especially at full load and at partial load has. Furthermore, the advantage of such an electric motor can be seen in the fact that the delivery volume is constant by the synchronous operation in the high load range.

With regard to the design of the permanent magnets so far no further details have been made.

Thus, an advantageous solution provides that the permanent magnets extend parallel to a rotor axis of the rotor.

Furthermore, it is preferably provided that the permanent magnets are formed as a plate body whose flat sides extend in a longitudinal direction and a transversely to the longitudinal direction transverse direction.

Conveniently, the permanent magnets are so in the rotor

arranged so that they are parallel to each other with their longitudinal direction

Rotor axis extend.

Furthermore, the permanent magnets are preferably arranged in the rotor such that they extend with their transverse directions along outer edges of a geometric polygon symmetrical to the rotor axis. With regard to the magnetization of the permanent magnets so far no further details have been made.

Thus, an advantageous solution that the permanent magnets formed as a plate body on their opposite flat sides, one of which faces the rotor axis and the other of the rotor axis facing away, have a different magnetic polarity, thereby easily planar magnetic poles in the rotor be available for synchronous operation of the electric motor.

In principle, the electric motor can be cooled in various ways.

An advantageous solution provides that the suction-side refrigerant path passes through the motor housing for cooling the electric motor.

In addition, as an alternative or in addition to the features of the semi-hermetic refrigerant compressor described so far, a further solution according to the invention provides that the refrigerant compressor is provided with an externally controllable or controlled mechanical power control unit.

Such an externally controlled power control unit provides the

Possibility without a frequency converter for the electric motor the

In particular, it provides the ability to reduce the mechanical load on the semi-hermetic refrigerant compressor by means of the mechanical power control unit, which is inexpensive and efficient, and moreover, offers the possibility of reducing the mechanical loads on the reciprocating compressor.

In particular, it is provided that the mechanical power control unit for reducing the power in at least one cylinder connects the outlet-side refrigerant path with the inlet-side refrigerant path. This creates the opportunity to operate the at least one cylinder so that it does not contribute to the compressor capacity.

This solution has the advantage that the mechanical loading of the components of the reciprocating compressor, then when a power reduction occurs, is low, since the refrigerant at a pressure level that is close to the inlet side, flows back from the outlet side to the inlet side with no large pressure fluctuations or even Pressure peaks and temperature peaks occur in the reciprocating compressor, in particular the

Reduce power reduction efficiency.

With regard to the arrangement of the mechanical power control unit, a wide variety of possible solutions are conceivable.

Thus, an advantageous solution provides that the mechanical power control unit is arranged on the cylinder head, whereby there is the advantage that with it the mechanical power control unit in a simple manner with

at least one of the cylinders can interact.

It is particularly favorable if the mechanical power control unit is at least partially integrated in the at least one cylinder head.

In order to be able to cooperate as optimally as possible with at least one cylinder, it is preferably provided that the power control unit for power reduction connects an exhaust chamber in the cylinder head with an inlet chamber in the cylinder head by means of a connecting channel.

Thus, a direct interaction of the power control unit with the at least one cylinder head associated with the cylinder is possible, so that thereby a compact design of the refrigerant compressor in such a built-in power control unit can be realized. It is particularly expedient if the connecting channel is arranged integrated in the cylinder head, so that thereby also the space required for the interaction of the power control unit with the inlet chamber and the outlet chamber can be optimized.

In particular, it is provided that the outlet chamber in the cylinder head is arranged directly adjacent to at least one outlet opening for the respective cylinder in the valve plate and thus in particular the

Outlet chamber also directly adjacent to the valve plate and the outlet opening, in particular with the exhaust valve adjacent.

Furthermore, it is preferably provided that the inlet chamber in the cylinder head is arranged directly adjacent to an inlet opening for the respective cylinder in the valve plate, so that the inlet chamber is directly adjacent to the valve plate and the inlet opening.

With regard to the way in which the mechanical power control unit opens or closes the connection channel between the outlet chamber and the inlet chamber, the most diverse possibilities are conceivable.

For example, it would be conceivable to use conventional slide designs.

A particularly advantageous solution provides that the mechanical power control unit for closing the connection channel has a closure piston.

Such a closure piston makes it possible, in particular with the shortest possible reaction time, to open or close the connection channel.

For reliable sealing of the closure piston is preferably sealed with a piston ring in a guide bore, in particular in the cylinder head, out. In particular, it is provided that the closure piston for closing the connection channel can be placed on a sealing seat, which runs around the connecting channel, so that when connecting the closure piston on the seal seat of the connecting channel is interrupted, while the connection channel is opened again when lifting the closure piston of the compression seat ,

In order to permanently achieve reliable sealing, it is preferably provided that a sealing region of the sealing piston which can be placed on the sealing seat is made of a metal which has a lower hardness than a metal from which the sealing seat is made, or vice versa.

The seal seat can be arranged in different ways.

A particularly advantageous and compact solution provides that the

Seal seat in a wall portion of the cylinder head is arranged, which separates the inlet chamber from the outlet chamber.

In this case, the seal seat either as part of the wall section

be formed or the seal seat is formed by an inserted into the wall portion of the cylinder head component.

Preferably, the seal seat is arranged so that it is arranged in a wall section extending above the valve plate and above the inlet chamber and thus, in particular, the seal seat at the same time constitutes an inlet opening for the inlet chamber opposite the valve plate. Furthermore, it is also preferably provided that the seal seat simultaneously represents an outlet opening for the outlet chamber, so that an immediate transition from the outlet chamber into the inlet chamber is realized by the seal seat.

For a spatially compact arrangement, it has proved to be particularly advantageous if the seal seat is arranged on a side of the inlet chamber opposite the valve plate.

A quick change of the closure piston between the closed position and the open position is preferably possible if, starting from the seal seat, the stroke of the closure piston is in the range of one quarter to one half of the mean diameter of the connection channel.

With regard to the assignment of the mechanical power control unit to individual cylinders, no further details have been given in connection with the previous explanation of the individual embodiments.

Thus, a solution provides that the mechanical power control unit is assigned to a cylinder and that, if necessary, a plurality of cylinders, a plurality of mechanical power control units are provided, wherein not necessarily a mechanical power control unit must be assigned to each cylinder.

A favorable solution provides that a cylinder head has an inlet chamber and an outlet chamber for a cylinder bank comprising at least two cylinders.

In this case, several cylinders are thus combined to form a cylinder bank. Advantageously, it is provided in such a solution that the respective mechanical power control unit of a cylinder bank,

in particular with at least two cylinders, is assigned.

In a refrigerant compressor with a plurality of cylinder banks, for example N-cylinder banks, it is preferably provided that at least

N-l cylinder banks associated with a mechanical power control unit.

However, in order to optimally reduce the performance of the refrigerant compressor, it is preferably provided that each cylinder bank a

mechanical power control unit is assigned.

In order to avoid a backflow of refrigerant under high pressure and thus a pressure drop at the outlet connection element in the event of a power reduction, a check valve is provided in the compressor housing section following the refrigerant paths that can be influenced by the mechanical power control unit.

Furthermore, it is preferably provided that the check valve has an outlet opening provided in the valve plate and a valve element cooperating with the valve plate, so that the valve plate can also be used for arranging and forming the check valve.

In particular, it is provided that the valve element is held on the valve plate, so that the valve plate is used not only for the formation of the inlet and outlet valves, but also for holding the valve element of the check valve.

With regard to the operation of the closure piston no further details have been made in connection with the previous explanation of the individual embodiments. Thus, an advantageous solution that the closure piston is acted upon in the direction of its cooperating with the sealing seat position by a compression spring, so that the compression spring ensures that the closure piston, for example, in the non-operating state of the refrigerant compressor, closes the connecting channel due to the action of the compression spring ,

Further, it is preferably provided that the closure piston can be actuated by a pressure chamber, which is acted upon by either suction pressure or by high pressure depending on the external control of the power control unit, wherein upon actuation of the pressure chamber by suction pressure of the closure piston moves into its open position and at a

Actuation of the pressure chamber by high pressure of the closing piston is acted upon in addition to the action of the compression spring in the direction of its closed position.

In particular, a volume of the pressure chamber is so small that, in the open position of the closure piston, it is less than a third, better still less than a quarter, even better less than one-fifth, more advantageously less than one-sixth and particularly advantageously less than one-seventh and even more advantageous smaller than one eighth of the maximum volume of the pressure chamber in the closed position of the closure piston.

This dimensioning of the pressure chamber allows to quickly change between the closed position and the open position, since the pressure must be changed only in a small volume between suction pressure and high pressure.

For each pressurization of the pressure chamber with high pressure or

Suction pressure is preferably provided by the power control unit comprising a drive unit, with which the pressurization of the

Locking piston is controllable. In order to carry out the power control of the refrigerant compressor, a power controller is preferably provided, which controls the at least one power control unit in accordance with a required compressor output.

The power control is in particular in connection with a higher-level system control and receives information from the system controller about the required compressor capacity.

In accordance with this information about the required compressor delivery rate, the power controller then controls the at least one or more power control units in such a way that the refrigerant compressor provides the required compressor delivery rate, but does not provide an unnecessarily high compressor delivery rate.

For this purpose, the refrigerant compressor is designed so that its maximum compressor capacity sufficient for the maximum required by the plant control compressor capacity and lower compressor delivery rates are achieved by power reduction by means of at least one power control unit 142.

In addition, a start-up control unit is preferably provided for the refrigerant compressor, in particular, the refrigerant compressor is provided with a start-up control unit which controls a start of the electric motor, which starts in the inventive solution as an asynchronous motor, until it has reached the synchronous speed, and then as a synchronous motor continues.

The start-up control unit can in different ways control the operation of the refrigerant compressor in order to start the electric motor in a suitable manner. In particular, the start-up control unit operates in such a way that it operates the electric motor for starting up with a starting current-reducing winding connection.

This could for example be realized with a switch from a star connection for starting in a triangular circuit after starting.

Thus, an advantageous solution that the startup control unit for

Start of the electric motor first energized a first partial winding and subsequently a second partial winding in a stator of the electric motor.

The starting of the electric motor with a first partial winding has the advantage that this makes it possible to reduce the starting current and thus to avoid, for example, a heavy load on the electrical supply network due to an excessive starting current.

Alternatively or additionally, the start-up control unit is designed so that it controls the power control when starting the electric motor so that the reciprocating compressor works when starting the electric motor only with reduced compressor capacity.

It is particularly favorable for the starting of the electric motor when the starting control controls the power control in such a way that the reciprocating compressor with the smallest possible when starting the electric motor

Compressor capacity works.

In this case, the smallest possible compressor delivery rate can be a compressor delivery rate at which one and more cylinders still work. A particularly favorable embodiment provides that the reciprocating compressor is so power controllable that at the smallest possible

Compressor flow rate is such that none of the cylinder compresses more refrigerant, so that thereby the torque required for the start of the reciprocating compressor is minimal.

In addition, provides an advantageous solution that the startup control, the power control controls such that after reaching the synchronous operation of the electric motor, the compressor delivery rate is gradually increased, for example, with the inclusion of another cylinder or another cylinder bank or possibly successive connection of other cylinders or more cylinder banks.

Regarding the operating conditions of the reciprocating compressor were in

Connection with the solution according to the invention made no further details.

In principle, the reciprocating compressor according to the invention can work with all refrigerants customary for semi-hermetic refrigerant compressors.

However, the solution according to the invention provides particular advantages for the operation of the reciprocating compressor, in particular for the damage-free operation of the reciprocating compressor when the reciprocating compressor operates with a suction pressure in the range of 10 bar to 50 bar.

Furthermore, the solution according to the invention is also in terms of

mechanical load of the reciprocating compressor then particularly advantageous when reciprocating compressor works with a high pressure in the range of 40 bar to 160 bar. In particular, the refrigerant compressor according to the invention can be used particularly advantageously when the reciprocating compressor works with carbon dioxide as a refrigerant and is designed especially for operation with carbon dioxide as a refrigerant.

Further features and advantages of the invention are the subject of the following description and the drawings of some

Embodiments.

In the drawing show:

Fig. 1 is a side view of an embodiment of a refrigerant compressor according to the invention;

FIG. 2 shows a plan view in the direction of the arrow A in FIG. 1 of the refrigerant compressor according to the invention; FIG.

Fig. 3 is a front view of the embodiment of the invention

Refrigerant compressor;

Fig. 4 is a half-sided offset section along line 4-4 in Fig. 2;

5 shows a longitudinal section through the refrigerant compressor according to the invention;

Fig. 6 is a section along line 6-6 in Fig. 7;

Fig. 7 is a section along line 7-7 in Fig. 6 at a closed

Connecting channel between inlet chamber and outlet chamber;

8 is a section similar to FIG. 7 with open connection channel

between the outlet chamber and the inlet chamber; FIG. 9 shows a section along line 9-9 in FIG. 5 through a rotor of the electric motor; FIG.

10 is a schematic representation of a startup of the electric motor, and

Fig. 11 is a section similar to Fig. 7 by a second embodiment.

An embodiment of a semi-hermetic refrigerant compressor according to the invention, shown in FIGS. 1 to 5, comprises an overall housing 10, in which a reciprocating compressor 12 and an electric motor 14 are arranged.

Preferably, the overall housing 10 includes a compressor housing portion 22, which constitutes an outer housing of the reciprocating compressor 12, and a motor housing portion 24, which constitutes an outer housing of the electric motor 14.

The overall housing 10 is preferably formed by a one-piece housing body 26 which extends in the direction parallel to a later explained in detail central axis 28 and on the compressor housing section 22 end side by means of a bearing cap 32 is closed and in the engine section 24 end with a cover 34 is closed.

In the compressor housing portion 22, a generally designated 42 compressor shaft extends coaxially to the central axis 28 between a arranged on the bearing cap 32 first shaft bearing 44 to a disposed between the reciprocating compressor 12 and the electric motor 14 second shaft bearing 46, wherein the second shaft bearing 46 at an in the housing body 26 formed in the middle wall 48 is held, which is a between the bearing cap 32 and the middle wall 48 lying drive space 52 defined by which the compressor shaft 42 extends through and in which eccentric 54 and 56 of the compressor shaft 42 are arranged, wherein on each of the eccentric 54 and 56, two connecting rods 62i and 62 ₂ , respectively 64i and 64 _2, are arranged, wherein the connecting rods 62i and 64i, the pistons drive 66i and 68i and the connecting rods 62 ₂ and 64 _2, the piston 66 ₂ and 68. ₂

The pistons 66 and 68 are guided in cylinder bores 72 and 74, which are formed by molded into the compressor housing section 22, in particular integrally molded, the cylinder housing 76, 78.

Each cylinder housing 76, 78 with the cylinder bore 72, 74 and the guided in this piston 66, 68 respectively forms a cylinder 82, 84th

The two first cylinders 82i and 84i formed in the compressor housing section 22 form a first cylinder bank 86i, while the two cylinders 82 ₂ and 84 _{2 formed} in the compressor housing section 22 form a second cylinder bank 86 ₂ .

In each of the cylinder banks 86i and 86 ₂ , the respective cylinder bores 72i and 74i and 72 ₂ and 74 _{2 are closed} by a common valve plate 88i and 88 ₂ , which tightly rests on the respective cylinder housings 76i and 78i and 76 ₂ and 78 ₂ , respectively and thus by the respective valve plate 88i and 88 ₂ and the respective piston 66i and 68i or 66 ₂ and 68 ₂ and the cylinder bores 72i and 74i or 72 ₂ and 74 ₂ bounding compression space limit.

The valve plates 88i and 88 ₂ are then in turn covered by cylinder heads 92i and 92 ₂ , respectively. In each of the cylinder heads 92i and 92 ₂ , as shown in Figs. 6 to 8, respectively, an inlet chamber 94 and an outlet chamber 96 are arranged, which are the two cylinders 82 and 84 of the respective cylinder bank 86 assigned.

Specifically, the inlet chamber 94 overlies inlet ports 102 and 104 of the cylinder 82 and inlet ports 106 and 108 of the cylinder 84.

Further, the discharge chamber 96 is located above the discharge ports 112 and 114 of the cylinder 82 and the exhaust ports 116 and 118 of the cylinder 84 provided with the exhaust valves 113, 115, 117, 119 seated on the valve plate 88, and is particularly adjacent directly this one.

As shown in FIGS. 6-8, each cylinder head 92 includes an outer body 122 which engages over the respective valve plate 88 and encloses the inlet chamber 94 and the outlet chamber 96, which in turn are separated by a separator 124 extending within the outer body 122 the separating body 124 rises from the respective valve plate 88 and extends across the inlet chamber 94 and extends across it.

Thus, the outlet chamber 96 is located in the region of the valve plate 88 laterally adjacent to the inlet chamber 94 and extends between the outer body 122 and the separator 124 at least partially over the inlet chamber 94th

For controlling the power, that is, for controlling the compressor delivery rate of the refrigerant compressor, each cylinder head 92 is associated with a mechanical power control unit 142 actively driven by a power controller 138, with which a communication passage 144 between the discharge chamber 96 and the inlet chamber 94 is closed or opened can be, wherein the cylinders 82, 84 associated with the cylinder head 92 with closed connection channel 144 (FIG. 7) compress the full-capacity refrigerant and no refrigerant when the connection channel is open since the refrigerant flows back from the outlet chamber 96 into the inlet chamber 94.

In this case, the connecting channel 144 extends through an insert part 146 inserted into the separating body 124, which forms a sealing seat 148 which faces the outlet chamber 96 and which adjoins a part of the outlet chamber 96 surrounding the sealing seat 148 and adjoining it.

Furthermore, the seal seat 148 faces a closure piston 152, which can be placed on the seal seat 148, for example, with a metallically formed sealing area 154 in order to seal the connecting channel 144 tightly and which can be lifted away from the seal seat 148 in such a way that the sealing area 154 is at a distance of the

Seal seat 148 is and thus refrigerant can flow from the outlet chamber 96 in the inlet chamber 94.

Preferably, the closure piston 152 is coaxial with the insert 146 with the seal seat 148 and sealed by a piston ring 153 guided in a guide bore 156 which is formed by a formed on the outer body 122 guide sleeve body 158 of the cylinder head 92.

Preferably, the closure piston 152 itself or at least the

Seal region 154 made of a metal, for example, a non-ferrous metal, which has a lower hardness than the metal of the seal seat 148, which is made for example of steel, in particular hardened steel. In order to allow rapid movement of the closure piston 152, in particular, a stroke of the closure piston 152 between a closed position and an open position is in the range between a quarter and a half of a mean pressure gauge of the connection channel 144.

The closure piston 152 delimits a pressure chamber 162 which is arranged on a side of the closure piston 152 facing away from the sealing region 154 and is closed by a closure member 164 on a side opposite the closure piston 152.

In particular, the volume of the pressure chamber 162 is so small that, in the open position of the closure piston, it is less than one-third, better still less than a quarter, even better less than one-fifth, advantageously less than one-sixth and even more advantageously less than one-eighth of the maximum Volume of the pressure chamber 162 in the closed position of the closure piston 152nd

Further, in the pressure chamber 162, a compression spring 166 is still arranged, which is supported on the one hand on the end body 164 and on the other hand, the closure piston 152 in the direction of its on the seal seat 148th

seated closing position acted upon.

Depending on the pressurization of the pressure chamber 162, the closure piston 152 can be moved into its open position shown in FIG. 8 or into its closed position shown in FIG. 7.

For this purpose, the closure piston 152 is penetrated by a throttle channel 172 which extends from the pressure chamber 162 through the closure piston 152 to an orifice 154, which is arranged radially outside the sealing region 154 on a side facing the seal seat 148, but in that they are radial outside of the sealing element 154 is located in the closed position of the closure piston 152 an inlet of pressurized in the outlet chamber 96 and the sealing seat flowing around the refrigerant allowed and throttled this the pressure chamber 162 feeds.

In addition, into the pressure chamber 162, for example, by the end body 164, a discharge channel 176, which is connected by a solenoid valve as a whole designated 182 with a pressure relief passage 184, which is in communication with the inlet chamber 94.

For example, the solenoid valve 182 is configured to include a valve body 186 for interrupting or establishing communication between the pressure relief passage 184 and the relief passage 176.

Once the connection between the discharge channel 176 and the pressure relief channel 184 has been established, the suction pressure prevails in the pressure chamber 162, while the closure piston 152 is acted upon by the pressure in the outlet chamber 96 on its side facing the outlet chamber 96 and thus moved into its open position.

However, if the connection between the pressure relief passage 184 and the discharge passage 176 is interrupted by the valve body 186, the compression spring 166 pushes the closure piston 152 on the seal seat 148 and additionally flows through the throttle passage 172 high pressure in the pressure chamber 162, so that in the pressure chamber 162nd High pressure builds up, in addition to the action of the compression spring 166, the closure piston 152 with the

Seal member 154 presses on the seal seat 148.

In particular, the closure piston 152 is formed such that it extends radially beyond the seal seat 148, so that even with the closure piston 152 in the closed position, the piston surface located radially outside the seal seat 148 and acted upon by high pressure causes the closure piston 152 is moved against the force of the compression spring 166 in the open position shown in Fig. 5, provided that the valve body 186 of the solenoid valve 182 connects between the discharge channel 176 and the pressure relief passage 184 produces what causes that in the pressure chamber 162 sets a suction pressure.

The supply of refrigerant under suction is effected via a feed passage 202 formed in the compressor housing section 22 leading to an inlet opening 204 leading to the valve plate 88, through which suction pressure refrigerant flows to a passage opening 206 in the valve plate 88 and through this into the inlet chamber 94 passes.

In addition, as shown in FIGS. 7 and 8, the discharge chamber 96 leads to an outlet port 212 disposed in the valve plate 88, through which the refrigerant under pressure in the discharge chamber 96 transfers into an exhaust passage 214 provided in the compressor casing section 22 and flows to an outlet port 216 can.

In particular, the outlet opening 212 of the valve plate 88 is associated with a check valve 222, which is held on the valve plate 88 and a valve element 224 is disposed on an outlet channel 214 facing side of the valve plate 88 and ensures that in the case of the open position of the closure piston 152 and thus in the case of an overflow of the refrigerant from the discharge chamber 96 into the inlet chamber 94, the pressure in the outlet channel 214 does not drop, but is maintained by the closing check valve 222.

Preferably, the check valve 222 together with a this

associated catch element 226 held by means of a holding element 226 on the valve plate 88 and seals against the valve plate 88 from. The refrigerant compressor according to the invention is as semi-hermetic

Compressor is formed so that under suction pressure refrigerant is supplied by means disposed on the end cap 34 inlet connection member 232 an engine compartment 234 and the electric motor 14 flows in the direction of the middle wall 48 and from the engine compartment 234 into the supply passage 202, so that by the supplied suction side refrigerant a cooling of the electric motor 14 in the engine compartment 234 takes place.

The electric motor 14 in turn comprises a fixedly held in the motor housing portion 24 stator 252 with a stator winding 254, which has, for example, two partial windings 256 and 258, the

Magnetization of a laminated stator core 262 serve.

The stator 252 encloses a rotor designated as a whole by 272, in whose rotor core 274, as shown in FIG. 9, on the one hand a short-circuit cage 276 is arranged, which comprises short-circuit bars 278 which run parallel to a rotor axis 282 and which are electrically conducting in the circumferential direction connected to each other.

Furthermore, plate-shaped permanent magnets 292 are inserted into the laminated core 274, whose flat sides 294 extend on the one hand with a longitudinal direction 296 parallel to the rotor axis 282 and extend transversely to the rotor axis 282 with a transverse direction 298 such that the transverse directions 298 extend about the rotor axis 282 as the axis of symmetry running around

forming geometric polygon.

The permanent magnets 292 are further configured such that in a circumferential direction 302 about the rotor axis 282 successive permanent magnets 292 each have an alternating polarity on their sides facing the rotor axis 282, so that overall the rotor 272 by means of the permanent magnets 292 in the direction of rotation alternating magnetic Pole has. An electric motor 14 provided with such a rotor 272 operates as a synchronous motor in normal operation due to the permanent magnets 292 provided in the rotor 272, whereby due to the permanent magnets 292 such a synchronous motor has an advantageous energy efficiency and higher refrigerant delivery rate.

The rotating field generated by the stator 252 to run due to a supply of the stator winding 254 at a defined frequency, for example, due to the fact that the stator winding 254 are fed by an AC power supply.

In order to enable a start-up at a rotating with a constant frequency rotating field of the stator 252, the rotor 272 is provided with the short-circuit cage 276, which creates the possibility that the electric motor 14 initially starts as an asynchronous motor until it reaches the rotational speed of the rotating field of stator development has reached and then rotates as a synchronous motor due to the conditional by the permanent magnet 292 magnetic poles.

Thus, a refrigerant compressor can be operated with such an electric motor powered by a conventional AC mains, since this starts as an asynchronous motor.

But it is also possible to operate such a refrigerant compressor with a frequency converter.

To facilitate the startup of the electric motor 14 is also the

Possibility to use a start-up control 312 assigned to the refrigerant compressor - as shown in FIG. 10 initially only one of the partial windings 256 or 258 to energize to reduce the starting current and then after a short start-up phase of the electric motor 14 as

Asynchronous the other part of the windings 258, 256 to switch. In the case of the use of the refrigerant compressor according to the invention for large pressure differences, for example as a compressor for CO ₂ , the start-up control 312 intervenes in the intended power control 138 for the active control of the power control units 142 and causes at least one cylinder bank 86, preferably, both cylinder banks 86i and 86 _{2 are} deactivated so that upon deactivating at least one cylinder bank 86, the torque required by the piston compressor 12 is reduced, and upon deactivating both cylinder banks 86i and 86 _2, the torque which is H ubkol benverdichter 12 is required, is low, since no compaction of refrigerant takes place, so that on the one hand, the starting current of the electric motor 14 is kept low and this d ieser on the other hand then very fast l from its operation as an asynchronous motor in the operation as a synchronous motor passes in which vol le torque is available, so either sliding Cylinder banks 86i and 86 ₂ can be activated in a timely or successive manner (FIG. 10).

In a second embodiment, shown in FIG. 11, those parts which are identical to those of the first embodiment are denoted by the same reference numerals, so that they are fully contained in FIG

Embodiments of the first embodiment can be made reference.

In contrast to the first embodiment, the catch element 226 'of the check valve 222' is formed in the compressor housing portion 22, for example, by a recess seitl I of the outlet channel 214, the union possible way of the valve member 224 'between its closed, on the valve plate 88 auflie entending Stel development and the maximum open position is limited. Such a catch element 226 'can generally be provided in all compressor housing sections 22 of all refrigerant compressors of the same module, regardless of whether they are provided with a check valve 222' or not, so that a simple retrofitting of the refrigerant compressor with a check valve 222 'and in particular with at least a mechanical power control unit 142 according to the invention together with such a check valve 222 'is possible.

Claims

P A T E N T A N S P R E C H E

A semi-hermetic refrigerant compressor comprising a reciprocating compressor (12) and an electric motor (14), an overall housing (10) having a motor housing portion (24) for the electric motor and a compressor housing portion (22) for the reciprocating compressor (12), one from a suction port (12). 232) on the overall housing (10) to an inlet chamber (94) of the reciprocating compressor (12) leading suction refrigerant path and one of an outlet chamber (96) of the reciprocating compressor (12) to a pressure port (216) on the overall housing (10) leading pressure side refrigerant path in which in the compressor housing portion (22) at least one cylinder (82, 84) of the reciprocating compressor (12) is provided, which in a in the compressor housing section (22) formed in the cylinder bore (72, 74) movable piston (66, 68), a Cylinder bore (72, 74) final valve plate (88) and the valve plate (88) cross and a part of the

Compressor housing section (22) has the cylinder head (92),

The electric motor (14) is designed as a synchronous motor, in the rotor (272) of which

Permanent magnets (292) for the synchronous operation of the electric motor (14) and a short circuit cage (276) for starting the electric motor (14) are arranged in the asynchronous operation.

Refrigeration compressor according to claim 1, characterized in that the permanent magnets (292) extend parallel to a rotor axis (282) of the rotor (272).

Refrigeration compressor according to claim 2, characterized in that the permanent magnets (292) are formed as a plate body, the flat sides (294) extending in a longitudinal direction (296) and a transverse to the longitudinal direction transverse direction (298).

4. Refrigerant compressor according to one of the preceding claims, characterized in that the permanent magnets (292) extend in each case with its longitudinal direction (296) parallel to the rotor axis (282).

5. Refrigerant compressor according to one of the preceding claims,

characterized in that the permanent magnets (292) extend with their transverse directions (298) along outer edges of a geometric polygon symmetrical to the rotor axis (282).

6. refrigerant compressor according to one of the preceding claims,

characterized in that the plate magnets formed as a permanent magnet (292) on their opposite flat sides (294), of which one of the rotor axis (282) facing away and the other of the rotor axis (282) faces away, a

have different magnetic polarity (N, S).

7. Refrigerant compressor according to one of the preceding claims,

characterized in that the suction-side refrigerant path passes through the motor housing (24) for cooling the electric motor (14).

8. A refrigerant compressor according to the preamble of claim 1 or any one of the preceding claims, characterized in that the refrigerant compressor is provided with an externally controlled mechanical power control unit (142).

9. refrigerant compressor according to the preamble of claim 1 or any one of the preceding claims, characterized in that the mechanical power control unit (142) for reducing the power at at least one cylinder (82, 84) connects the outlet side refrigerant path with the inlet side refrigerant path.

10. refrigerant compressor according to claim 8 or 9, characterized in that the mechanical power control unit (142) on the at least one cylinder head (92) is arranged.

11. A refrigerant compressor according to claim 10, characterized in that the mechanical power control unit (142) is at least partially integrated in the at least one cylinder head (92).

12. A refrigerant compressor according to any one of claims 8 to 11, characterized in that the mechanical power control unit (142) for output reduction, an outlet chamber (96) in the cylinder head (92) with an inlet chamber (94) in the cylinder head (92) by means of a connection channel (144). combines.

13. Refrigerant compressor according to claim 12, characterized in that the connecting channel (144) is arranged integrated in the cylinder head (92).

14. Refrigerant compressor according to one of the preceding claims,

characterized in that the exhaust chamber (96) is disposed in the cylinder head (92) immediately adjacent to at least one exhaust port (112, 114, 116, 118) for the respective cylinder (82, 84) in the valve plate (88).

15. Refrigerant compressor according to one of the preceding claims,

characterized in that the inlet chamber (94) is disposed in the cylinder head immediately adjacent an inlet port (102, 104, 106, 108) for the respective cylinder (82, 84) of the valve plate (88).

16. Refrigerant compressor according to one of claims 8 to 15, characterized in that the mechanical power control unit (142) for closing the connecting channel (144) has a closure piston (152).

17. A refrigerant compressor according to claim 16, characterized in that the closure piston (152) for closing the connecting channel (144) on a sealing seat (148) can be placed, the

Connecting channel (144) extends around.

18. A refrigerant compressor according to claim 16 or 17, characterized in that a sealing region (154) of the closure piston (152) is made of a metal having a lower hardness than a metal from which the seal seat (148) is made.

19. A refrigerant compressor according to claim 17 or 18, characterized in that the seal seat (148) in a wall portion (124) of the cylinder head (92) is arranged, which separates the inlet chamber (94) from the outlet chamber (96).

20. A refrigerant compressor according to any one of claims 17 to 19, characterized in that the seal seat (148) in a over the valve plate (88) and over the inlet chamber (94) extending wall portion (124) is arranged.

21. Refrigerant compressor according to one of claims 17 to 20, characterized in that the sealing seat (148) on one of the valve plate (88) opposite side of the inlet chamber (94) is arranged.

22. A refrigerant compressor according to any one of claims 17 to 21, characterized in that starting from the seal seat (148) is a stroke of the closure piston (152) in the range of one quarter to half of a mean diameter of the connecting channel (144).

23. Refrigerant compressor according to one of the preceding claims,

characterized in that a cylinder head (92) has an inlet chamber (94) and an outlet chamber (96) for a cylinder bank (86) comprising at least two cylinders (82, 84).

24. Refrigerant compressor according to one of the preceding claims,

characterized in that the respective mechanical power control unit (142) is associated with a cylinder bank (86).

25. Refrigerant compressor according to one of the preceding claims,

characterized in that at N-cylinder banks (86) of the refrigerant compressor at least N-l-cylinder banks (86) a

mechanical power control unit (142) is assigned.

26. Refrigerant compressor according to one of claims 23 to 25, characterized in that each cylinder bank (86) is associated with a mechanical power control unit (142).

27. Refrigerant compressor according to one of the preceding claims,

characterized in that a check valve (222) is provided in the compressor housing section (22) following the refrigerant paths that can be influenced by the mechanical power control unit (142).

28. A refrigerant compressor according to claim 27, characterized in that the check valve (222) has an outlet opening (212) provided in the valve plate (88) and a valve element (224) cooperating with the valve plate (88).

29. Refrigerant compressor according to claim 28, characterized in that the valve element (224) on the valve plate (88) is held.

30. Refrigerant compressor according to one of claims 16 to 29, characterized in that the closure piston (152) in the direction of its with the seal seat (148) cooperating position by a compression spring (166) is acted upon.

31. Refrigerant compressor according to one of claims 16 to 30, characterized in that the closure piston (152) by a pressure chamber (162) is actuated, which can be acted upon by either suction pressure or by high pressure depending on the external control of the power control unit (142).

32. Refrigerant compressor according to claim 31, characterized in that the pressure chamber (162) in the open position of the closure piston (152) has a volume which is smaller than a third, better smaller than a quarter of the maximum volume of the pressure chamber (162) in the closed position.

33. Refrigerant compressor according to one of claims 8 to 32, characterized in that one of the power control unit (142) comprising drive unit (182) is provided, with which the pressurization of the closure piston (152) is controllable.

34. Refrigerant compressor according to one of claims 8 to 33, characterized in that a power control (138) is provided, which controls the at least one mechanical power control unit (142) corresponding to a required compressor capacity.

35. Refrigerant compressor according to one of the preceding claims, characterized in that a start-up control unit (312) is provided, which controls a start-up of the electric motor (14).

36. Refrigerant compressor according to claim 35, characterized in that the start-up control unit (312) operates the electric motor (14) for starting with a starting-current-reducing winding connection.

37. Refrigerant compressor according to claim 35 or 36, characterized in that the start-up control unit (312) for starting the

Electric motor (14) first a first partial winding (256) and subsequently a second partial winding (258) in a stator (252) of the electric motor (14) energized.

38. Refrigerant compressor according to one of claims 35 to 37, characterized in that the start-up control unit (312) controls the power control (138) when starting the electric motor (14) so that the reciprocating compressor (12) when starting the electric motor (14) only with reduced compressor capacity works.

39. Refrigerant compressor according to claim 38, characterized in that the start-up control unit (312) controls the power control (138) such that the reciprocating compressor (12) when starting the electric motor (14) operates with the smallest possible compressor capacity.

40. Refrigerant compressor according to one of the preceding claims, characterized in that the reciprocating compressor (12) operates with a suction pressure in the range of 10 bar to 50 bar.

41. Refrigerant compressor according to one of the preceding claims, characterized in that the reciprocating compressor (12) operates at a high pressure in the range of 40 bar to 160 bar.

42. Refrigerant compressor according to one of the preceding claims, characterized in that the reciprocating compressor (12) operates with carbon dioxide as refrigerant and is designed in particular for operation with carbon dioxide as a refrigerant.