EP0147855B1

EP0147855B1 - Refrigerating system

Info

Publication number: EP0147855B1
Application number: EP84116379A
Authority: EP
Inventors: Youichi Nakamura
Original assignee: Saginomiya Seisakusho Inc
Current assignee: Saginomiya Seisakusho Inc
Priority date: 1983-12-28
Filing date: 1984-12-27
Publication date: 1989-10-11
Also published as: DE3480113D1; JPS60140072A; EP0147855A2; EP0147855A3

Description

The present invention relates to a refrigerating system according to the precharacterizing portion of claim 1.
Improvement in power efficiency of the refrigerator is achieved by balancing the cooling medium pressure before and after the compressor when the compressor is stopped and by blocking the flow of condensed medium into the evaporator while at the same time keeping the high pressure of the condensed medium in the condensor, in order to reduce the restarting load.
For this purpose, it has been the common practice to provide a solenoid valve between the condensor and the capillary tube, which is operated by the compressor operation signal in such a way that it is opened during operation of the compressor and closed while in halt. With refrigerators which are usually used continuously for many hours, however, it is desirable to eliminate use of the solenoid valve even if the power consumption of the solenoid valve is small. It has also been pointed out that the solenoid valve operation can be noisy depending on the location of the refrigerator.
In recent years, therefore, a technology has been developed that employs a pressure valve in place of the solenoid valve.
With the DE-A-3314140 a refrigeration system is being disclosed comprising:

a condenser and an evaporator connected in series with each other, first throttle means provided in said series connection between said condenser and said evaporator,
a rotary compressor having a delivery side and a suction side, said delivery side being connected to said condenser, said suction side being connected to said evaporator,
a check valve provided between said evaporator and said suction side of said rotary compressor,
a differential pressure valve provided between said first throttle means and said evaporator, a pressure introducing tube communicating the suction side of said rotary compressor with said differential pressure valve, and
a second throttle means provided between said evaporator and said differential pressure valve.

The function of said differential pressure valve depends essentially from the reliability and the resilience of said foldable skin which, however, cannot be guaranteed.
It is therefor an object of the invention to propose a differential pressure valve for a refrigeration system which does reliably function and can rapidly be actuated.
This object will be solved by the subject matter of claim 1. Further advantageous embodiments are characterized within the sub-claims.
A preferred embodiment of the invention will be described below by means of the drawings. It is shown:

Fig. 1 a length cross section of a preferred embodiment of a difFerential pressure valve of the invention and
Fig. 2 an explanatory drawing of a refrigeration system using the differential pressure valve according to Fig. 1.

The differential pressure valve V1, as shown in Fig. 1, has a primary port 2 and a secondary port 3 formed in its body 1. Between these ports is formed a valve seat 4 with which a ball 5 comes into or out of contact. The ball 5 is provided on the secondary port side. At the top of the valve body 1 is mounted a diaphragm 8 which is held at its periphery by upper and lower covers 6, 7. A pressure chamber is formed in the upper cover 6 and is communicated with the pressure introducing tube F. A valve rod 9 is abutted against the underside of the diaphragm 8 and a spring 10 is installed between the rod 9 and the lower cover 7. The primary port 2 is connected with a pipe E1 coming from the capillary tube C and the secondary port 3 with a pipe E2 leading to an evaporator D described below.
In the above construction, during the operation of a rotary compressor A, the pressure loss of said evaporator D and the force of spring 10 combines to cause the ball 5 to open, thus performing the cooling operation. When the compressor is stopped, said differential pressure valve V1 closes because of pressure increase on the suction side caused by back flow from said rotary compressor A and because of the pressure drop at the input of said evaporator D or secondary port 3 caused by the absence of the evaporator's pressure loss.
In this construction the differential pressure valve is actuated by a small pressure difference between the pressure on the rotary compressor suction side and the relatively low pressure at the entrance of the evaporator. Therefore, once the operation starts, the pressure at the entrance of the evaporator becomes higher than the pressure on the suction side of the compressor whatever the external atmospheric condition may be. This enables the valve to be opened by a small spring load. That is, the differential pressure valve can be actuated by a slight pressure increase at the suction of the rotary compressor caused by the back flow of high pressure liquid. Thus, it is possible to prevent the back flow of high pressure liquid to the evaporator by rapidly actuating the differential pressure valve when the rotary compressor stops.
In the technique employed in the previous application, a capillary tube is provided as a throttle before the differential pressure valve. The cooling medium after passing through the throttle is reduced in pressure and can absorb heat, and therefore there is an energy loss in the pipe section leading to the refrigerating box.
To avoid this, it is desirable to install inside the refrigerating box the pipe section after the throttle including the valve. However, this is difficult due to space limitation.
To overcome the above drawback, the present invention has throttles before and after the differential pressure valve, with all these installed outside the refrigerating box, to perform the pressure reduction in two stages, thereby preventing energy loss while maintaining response speed of the differential pressure valve when the compressor operation stops.
Fig. 2 shows an embodiment of the present invention. A rotary compressor A, a condenser B, a capillary tube C, a differential pressure valve V1, a second capillary tube C', an evaporator D, and a check V2 are provided. More specifically, said condenser B and said evaporator D are connected in series with each other. A first capillary tube C is provided in said series connection between said condenser B and evaporator D. Said rotary compressor A has a delivery side and a suction side. Said delivery side is connected to the condenser B whereas said suction side is connected to the evaporator D. Between said evaporator D and the suction side is provided the check valve V2.
Said differential pressure valve V1 is provided between the first capillary tube C and the evaporator D and has a valve section Vs and the control section Cs. Said second capillary tube C' is provided between the differential pressure tube V1 and the evaporator D. There is further provided a pressure introducing tube F communicating the suction side of the rotary compressor with the control section Cs of the differential pressure valve V1.
Said valve section Vs of the differential pressure valve V1 includes a valve body 1 having a primary port 2 and a secondary port 3. Said primary port 2 communicates. with the first capillary tube C whereas said secondary port 3 communicates with the second capillary tube C'. Further, said primary port 2 defines a valve seat 4 within the valve body 1. Said valve body 1 has a bore l' formed therein communicating with the first primary port 2 and the second primary port 3. A ball is housed within said bore 1' and adapted to rest on said valve seat 4. Said valve body 1 is formed with an annular groove 1" around said bore 1' at an axial end thereof.
Said control section Cs includes a housing H, a diaphragm 8 provided within said housing H to divide the same into a first chamber R1 and a second chamber R2 and a valve rod 9 extending within said second chamber longitudinally movably. Said valve rod 9 has a ring member 9' attached to the first end thereof to abut against the diaphragm 8. In other words, said diaphragm 8 is held at its periphery by upper and lower covers 6 and 7. Said first chamber R1 of the control section Cs communicates with the pressure introducing tube F. Said lower cover 7 has an opening to communicate said second chamber with the secondary port 3. Said valve body 1 is attached to the lower cover 7 such that said annular groove 1" and said bore 1' communicates with the second chamber R2. Thus, the valve rod 9 is allowed to extend out of the control section Cs into the bore 1' to actuate the ball 5 at a second end thereof for closure of the primary port 2. There is further provided a coil spring 10 within said annular groove 1" between the body 1 and the ring member 9'.
A star-shaped leaf spring 23 having radially extending portions is provided between the coil spring 10 and the ring member 9'. Said radially bent portions are bent to extend within said annular groove 1" and expand radially outward to contact the valve body 1 within the annular groove 1".
Since the pressure in the secondary port which is opposed, through the diaphragm 8, by the pressure increase at the suction side caused by back flow from the rotary compressor A, is intermediate between the pressure at the first stage throttle C and that at the second stage throttle C', the differential pressure valve can be quickly actuated. Also the capillary tube C' as a second stage throttle to achieve a desired pressure reduction can be installed inside the refrigerating box thus eliminating energy loss.
Since this invention has the above construction, the differential pressure valve can rapidly be actuated when the rotary compressor is stopped, thereby reducing the restarting load and eliminating energy loss during operation.

Claims

1. Referigerating system comprising

(a) a condenser (b) and an evaporator (D) connected in series with each other,

(b) first throttle means (C) provided in said series connection between said condenser (B) and said evaporator (D),

(c) a rotary compressor (A) having a delivery side and a suction side, said delivery side being connected to said condenser (B), said suction side being connected to said evaporator (D),

(d) a check valve (V₂) provided between said evaporator (D) and said suction side of said rotary compressor (A),

(e) a differential pressure valve (V,) provided between said first throttle means (C) and said evaporator (D),

(f) a pressure introducing tube (F) communicating the suction side of said rotary compressor (A) with said differential pressure valve (V_I), and

(g) a second throttle means (C') provided between said evaporator (D) and said differential pressure valve (V_i), characterized in

(h) that said differential valve (V₁) has a valve section (V_s) and a control section (C_s),

(i) that said valve section (V_s) of said differential pressure valve (V₁) includes a valve body (1) having a primary port (2) therein communicating with said first throttle means (C) and defining a valve seat (4) within said valve body (1) and a secondary port (3), and a ball (5) housed within said valve body (1) and adapted to rest on said valve seat (4),

(j) that said control section (C_s) includes a housing (H/6, 7), a diaphragm (8) provided within said housing (H/6, 7) to divide the same into a first chamber (R_i) and a second chamber (R₂), and a valve rod (9) extending within said second chamber (R₂) longitudinally movably and abutting against said diaphragm (8) at a first end thereof,

(k) said first chamber (R₁) of said control section (C_s) communicates with said pressure introducing tube (F),

(I) said second chamber (R₂) of said control section (C_s) has an opening (1') to communicate said same second chamber (R₂) with the secondary port (3) and to allow said valve rod (9) to extend out of said control section (C_s) into said valve section (V_s) to actuate at a second end thereof said ball (5) for closure of said primary port (2),

(m) that said valve rod (9) has a ring member (9') attached to said first end thereof and abutting against said diaphragm (8) at its first end,

(n) that a resilient means (10) is provided for maintaining the abutment of said valve rod (9) against said diaphragm (8), and

(o) that a leaf spring (23) is provided held between said resilient means (10) and said ring member (9') within said second chamber (R₂) of said valve body (1), said leaf spring (23) having radially extending portions bent to extend within said valve body (1) and to expand outwardly to contact said valve body (1).

2. Refrigeration system according to claim 1, characterized in that said valve body (1) is formed with a bore (1') in communication with said primary port (2) and said secondary port (3).

3. Refrigeration system according to claim 1 or 2, characterized in that said valve boy (1) has an annular groove (1") around said bore (1') at an axial end thereof.

4. Refrigeration system according to one or more of the claims 1 to 3, characterized in that said resilient means (10) includes a coil spring (10) installed within said annular groove (1") between said valve body (1) and said ring member (9').

5. Refrigeration system according to claims 3 or 4, characterized in that said leaf spring (23) is star-shaped and that said radially extending portions bent to extend within said annular groove (1") and to expand outwardly to contact said valve body (1) within said annular groove (1").