EP3067645A1

EP3067645A1 - Optimized multi-purpose refigeration circuit

Info

Publication number: EP3067645A1
Application number: EP16160032.5A
Authority: EP
Inventors: Mauro Mantovan
Original assignee: Hiref SpA
Current assignee: Hiref SpA
Priority date: 2015-03-12
Filing date: 2016-03-11
Publication date: 2016-09-14

Abstract

A multi-purpose refrigeration circuit (1) having a plurality of utilities (U; U1, U2, U3), each of which is suited to request an operating temperature that is different from the one of the other utilities (U; U1, U2, U3), a compressor (2), a plurality of branches (R; R1, R2, R3), and one or more solenoid valves (S; S1, S2, S3), each of which is installed downstream of the compressor (2) and along a respective branch (R1; R2; R3); and one or more non-return valves (V; V1, V2, V3), each of which is installed in series and/or in parallel to a respective solenoid valve (S1; S2; S3).

Main figure: figure 1

Description

The present patent application concerns a refrigeration circuit, in particular a refrigeration circuit for a multi-purpose machine.
It is known that a multi-purpose refrigeration machine comprises a refrigeration circuit in which the refrigerant fluid flows, a compressor for circulation of the refrigerant fluid, and a plurality of utilities which are adapted to request hot or cold independently from one other (for example one utility can request hot domestic water while another utility can request cold air).
The multi-purpose refrigeration circuit comprises, in turn, a plurality of valves, each of which is adapted to regulate forward movement of the exchanger fluid inside the refrigeration circuit so as to obtain temperature levels that can be distributed to the different utilities.
Piston servo-controlled solenoid valves are commonly used inside a refrigeration circuit of this type. The operation of said valves does not depend solely on the magnetic field produced by passage of the current in a coil; a minimum inlet pressure is also necessary such as to move a piston and keep it raised from a main opening. The opening/closing of the main valve seat is controlled by the piston, while opening/closing of the pilot hole is controlled by the mobile core of the coil. These valves cannot operate with a zero pressure differential.
If installed in multi-purpose refrigeration circuits and in branches downstream of a compressor, the solenoid valves of known type have the drawback that the opening/closing command may not be definitive either because the design conditions of the solenoid valve do not fully occur or because downstream of the solenoid valve a higher pressure occurs than the pressure upstream (with flow direction opposite to the design direction). Therefore, the solenoid valve of known type may not remain perfectly sealed, due to fluttering of the shutter. In these operating conditions the solenoid valves can be subject to temperatures around 100°C and the fluttering of the shutter on the seal made of thermoplastic material results in the long term in a deterioration of the seal, with consequent leakage of refrigerant fluid. In the most extreme cases, the leakage of the refrigerant fluid can cause breakage of the compressor.
The object of the present invention is to provide a refrigeration circuit that overcomes the drawbacks described above.
The object of the present invention is to provide a refrigeration circuit as claimed in the attached claims.
The invention will now be described with reference to the accompanying drawing, which illustrates a non-limiting embodiment example thereof, in which:

figure 1 illustrates a diagram of a refrigeration circuit according to the present invention.

In figure 1, the number 1 indicates as a whole a multi-purpose refrigeration circuit comprising, in turn, a compressor 2, a plurality of utilities U and a plurality of branches R.
The compressor 2 is adapted to ensure the flow of refrigerant fluid F inside the circuit 1, while the utilities U are adapted to work at temperatures differing from one another. In particular a utility R1 is adapted to request hot, while the other utility is adapted to request cold; for example, to obtain hot water and cold air.
The circuit 1 further comprises a plurality of solenoid valves S. According to the example illustrated in figure 1, the circuit 1 comprises three solenoid valves S1, S2 and S3, each of which is installed along a respective branch R1, R2 and R3. The branches R1, R2 and R3 are installed downstream, with respect to the direction of forward movement of the refrigerant fluid, of the compressor 2. The branches R1, R2 and R3 are connected directly to the delivery of the compressor 2. Each solenoid valve S1, S2 and S3 is connected directly to the delivery of the compressor; in other words, each solenoid valve S1, S2 and S3 is connected by means of a respective branch directly to the delivery of the compressor 2, without the interposition of other hydraulic elements.
Advantageously, thanks to the presence of the solenoid valves S1, S2, S3 directly downstream of the compressor 2 it is possible to regulate, in an extremely efficient and substantially instantaneous manner, the flow rate of the refrigerant fluid to be sent to the different utilities R1, R2 and R3, as required. However, as will be illustrated better below, the solenoid valves S1, S2, S3 positioned directly downstream of the compressor 2 are subject to thermal and pressure stress resulting in fluttering which causes a high level of wear on the solenoid valves S1, S2, S3.
In order to prevent this type of fluttering and guarantee long life of the solenoid valves S1, S2, S3, the circuit 1 further comprises a plurality of by-pass branches B each of which is connected in parallel to a respective branch R. According to the illustration of figure 1, the circuit 1 comprises three by-pass branches B1, B2 and B3. The by-pass branch B1 is in parallel to the branch R1, the by-pass branch B2 is in parallel to the branch R2 and the by-pass branch B3 is in parallel to the branch R3.
The refrigeration circuit 1 further comprises a plurality of non-return valves V, each of which is associated with a respective solenoid valve S. According to the illustration of figure 1, the circuit 1 comprises three non-return valves V1, V2, and V3. The valve V1 is installed along the by-pass branch B1 in parallel to the solenoid valve S1 and can be flowed through by a flow in an opposite direction with respect to the direction in which the solenoid valve S1 is flowed through.
The valve V2 is installed along the by-pass branch B2 in parallel to the solenoid valve S2 and can be flowed through by a flow in an opposite direction with respect to the direction in which the solenoid valve S2 is flowed through.
The valve V3 is installed along the by-pass branch B3 in parallel to the solenoid valve S3 and can be flowed through by a flow in an opposite direction with respect to the direction in which the solenoid valve S3 is flowed through.
The circuit 1 further comprises, in a known way and illustrated schematically: a liquid receiver LR, an expansion valve VE and a liquid separator LS.
According to an embodiment not illustrated, the multi-purpose refrigeration circuit comprises one or more non-return valves, each of which is installed in series downstream of a respective solenoid valve S; in which the flow-through direction of each non-return valve is equal to the flow-through direction of the respective solenoid valve.
According to an embodiment not illustrated, the multipurpose refrigeration circuit comprises a plurality of solenoid valves and a plurality of non-return valves, in which one or more non-return valves are installed in series to the respective solenoid valves while the other non-return valves are installed in parallel to the respective solenoid valves. According to an embodiment not illustrated, the refrigeration circuit further comprises an electromechanical control system or a control system with microprocessor to regulate the opening of each solenoid valve S, according to the requirements of each utility U.
In use, if a pressure difference occurs in the refrigerant fluid between the position upstream and downstream of a solenoid valve S, the respective non-return valve V prevents the refrigerant flow pushing against the shutter of the solenoid valve. If the non-return valve V is installed in series to the solenoid valve S, the refrigerant fluid is stopped directly by the non-return valve V. If there is a by-pass branch B, the flow is diverted into the by-pass branch B and substantially returned to the inlet of the solenoid valve S, thus avoiding undue use of said solenoid valve S.
The refrigeration circuit 1 of the type described above allows the flow of refrigerant fluid at different temperatures to be guided into different portions to meet the requirements of the different utilities U, significantly reducing wear on the components of the refrigeration circuit 1. The refrigeration circuit 1 of the type described above can be used without distinction with all types of refrigerant fluids commonly used.

Claims

A multi-purpose refrigeration circuit (1) comprising a plurality of utilities (U; U1, U2, U3), each of which is adapted to request an operating temperature that is different from the one of the other utilities (U; U1, U2, U3), a compressor (2), a plurality of branches (R; R1, R2, R3), and one or more solenoid valves (S; S1, S2, S3), each of which is installed downstream of the compressor (2) and along a respective branch (R1; R2; R3); the refrigeration circuit (1) being characterized in that it comprises one or more non-return valves (V; V1, V2, V3), which are associated with said solenoid valves (S; S1, S2, S3); each one of said non-return valves (V; V1, V2, V3) being installed in series and/or in parallel to a respective solenoid valve (S1; S2; S3).
A refrigeration circuit (1) according to claim 1 and comprising one or more bypass branches (B; B1, B2, B3), each of which is arranged in parallel to a respective solenoid valve (S1; S2; S3); wherein each non-return valve (V1; V2; V3) is installed along a respective bypass branch (B1; B2; B3); wherein each non-return valve (V1; V2; V3) can be flowed through in a direction that is opposite to the direction in which the respective solenoid valve (S1; S2; S3) is flowed through.
A refrigeration circuit (1) according to claim 1, wherein a non-return valve (V1; V2; V3) is installed in series to and downstream of a respective solenoid valve (S1; S2; S3); wherein said non-return valve is suited to be flowed through by a fluid in the same direction in which the respective solenoid valve (S1; S2; S3) is flowed through.
A refrigeration circuit (1) according to one of the preceding claims and comprising a control unit (C), which is connected to each solenoid valve (S1; S2; S3); wherein the control unit (C) determines the opening or closing of each solenoid valve (S1; S2; S3) relative to the requests of each utility (U).
A refrigeration circuit (1) according to claim 3, wherein the control unit (C) comprises an electromechanical system and/or a microprocessor.
A refrigeration circuit (1) according to claim 1, wherein each solenoid valve (S1; S2; S3) is directly connected to the delivery of the compressor (2).