JPH03175243A - Delayed-open type solenoid valve - Google Patents

Abstract

PURPOSE:To restrain and ease the abrupt inflow of refrigerant without using a special controller by a method wherein a pilot type refrigerant on-off valve is provided on a pipe upstream an expander in a refrigerating circuit and its main valve is brought in action after the refrigerant pressure on the outlet side is increased to some extent. CONSTITUTION:Where flow resistances of a leakage flow path 2a, bypass flow path 1f and pressure equalizing pipe 2b and A, B and C, those flow paths are designed so that a relationship of A > B > C is established, and where the refrigerant flow resistance of an expansion valve is D, D >= B. When the difference between pressures in a back pressure chamber 1e and a low pressure chamber 4c decreases gradually and becomes less than the compression force of a valve spring 6, a differential pressure valve 5 closes the pressure equalizing pipe 2b. As a result, the pressure in the back pressure chamber 1e sharply drops because the refrigerant is fed into the back pressure chamber 1e only from the leakage flow path 2a and the refrigerant rapidly flows out through the bypass flow path 1f. Therefore, a main valve disc 2 is pushed up by the refrigerant pressure in a valve chamber 1a against the compression force of the valve spring 6, and the refrigerant is directly supplied from an upstream flow path 1b to a downstream flow path 1d.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a pilot system for controlling the supply of refrigerant in a refrigeration circuit, particularly a refrigeration circuit equipped with a plurality of evaporative heat exchangers that are used independently. Regarding mold opening/closing valves.

[Conventional technology]

In refrigeration equipment such as prefabricated refrigerated warehouses that include a plurality of independent refrigerator compartments or freezer compartments, a refrigerant compressor is constantly operated to supply refrigerant only to the necessary refrigerator compartments. In such a case, an on-off valve for controlling the supply of refrigerant is usually installed in front of each evaporative heat exchanger, particularly just before the expander.

Conventionally, when a manual stop valve or the like was used as such an on-off valve, the valve was opened gradually to prevent the refrigerant stagnant in the piping on the upstream side of the valve from rushing into the expander. . However, if an attempt is made to use a solenoid valve, such as a solenoid pilot valve, for remote control, the valve cannot be opened rapidly, causing refrigerant to rush into the valve. In addition, compressors have recently become larger, and solenoid control valves are now installed together with heat exchangers, expansion valves, etc. in the freezing chamber, so liquefaction can occur in the piping on the inlet side of the solenoid control valve. The refrigerant flowing into the refrigerant flows in at the same time as the electromagnetic control valve opens, collides with the expander, e.g., the expansion valve, and generates an impact noise, which not only vibrates the refrigerant piping, but also sometimes destroys the expansion valve, etc. There were other problems.

In order to alleviate the intrusion of liquid refrigerant at the start of operation of the freezer compartment, a small diameter sub solenoid valve is installed in parallel with the main solenoid valve for controlling the supply of refrigerant, and the sub solenoid valve is opened first. The idea is to control the main solenoid valve to open after an appropriate delay time. However, connecting solenoid valves in parallel with piping complicates the piping work, increases equipment costs, increases the chance of contamination with dirt, etc., and has the disadvantage of making failures more likely.

[Problem to be solved by the invention]

Therefore, the present invention provides a slow-acting, delayed-opening solenoid valve that can be used for refrigerant supply control and does not have the above-mentioned drawbacks, and can suppress and alleviate the rush of refrigerant without using a special control device. This is what we are trying to provide.

[Means for Solving the Problems] A delayed-opening solenoid valve as an object of the present invention is a pilot-type on-off valve for controlling refrigerant that is provided upstream of an expander in a refrigeration circuit via a pipe line, and comprises: A controlled flow path in which a leakage flow path, a back pressure chamber, and a bypass flow path that can be shut off by a pilot valve are connected in series is provided between the upstream path and the downstream path,
A main valve that opens when the resultant force of the back pressure chamber pressure and the pressing force of the valve spring is lower than the upstream passage pressure is provided between the upstream passage and the downstream passage in parallel with the control passage, and the downstream passage pressure is A control delay flow path, in which a differential pressure valve and a pressure equalization flow path are connected in series, is connected between the upstream passage and the back pressure chamber, and the pressure equalization flow path is closed when the resultant force of the pressure force of the valve spring exceeds the back pressure chamber pressure. The flow resistance of the refrigerant of the leakage flow path, the bypass flow path, the pressure equalization flow path, and the expansion device is set to A, B, C, respectively.
When D, it is characterized in that A>B>C and D≧B.

[For production]

The delayed opening type solenoid valve of the present invention has a refrigerant supply pipe from a compressor connected to the upstream side, and an expansion valve and an evaporation heat exchanger connected to the downstream side via a connecting pipe. and installed in the freezing room. In such refrigeration equipment, when the compressor is operated to operate another freezer compartment and the delayed opening solenoid valve is closed, the refrigerant in the piping upstream of the valve is liquefied. Furthermore, most of the refrigerant in the system after the coupling pipe on the downstream side of the valve is suctioned and recovered by the compressor, leaving only low-pressure gas. Therefore, the upstream refrigerant fills the back pressure chamber, and the differential pressure valve is open, allowing the refrigerant to freely flow through the pressure equalization channel.

When the pilot valve is first opened in this condition, the refrigerant in the back pressure chamber partially vaporizes and flows into the downstream piping through the bypass flow path, and the refrigerant flows into the back pressure chamber through the leakage flow path and the pressure equalization flow path. Since the back pressure is supplied, the pressure inside the back pressure chamber does not immediately become low F. Therefore, the refrigerant on the upstream side flows into the downstream piping while partially vaporizing at a flow rate limited by the flow resistance of the bypass flow path, but the amount of inflow is small and collides with the expansion valve, causing impact noise and vibration. It never occurs. Since the flow resistance of the expansion valve is not smaller than the flow resistance of the bypass flow path, the pressure in the downstream pipe of the delayed opening type solenoid valve leading to the expansion valve gradually increases.

In this way, when the resultant force of the downstream passage pressure and the pressing force of the valve spring exceeds the back pressure chamber pressure, the differential pressure valve closes and the flow in the pressure equalizing passage is stopped. In this case, the refrigerant will only flow into the back pressure chamber through the leakage path with high flow resistance, so the pressure in the back pressure chamber will drop rapidly and the main valve will open, and the liquid refrigerant in the upstream pipe will flow through the main valve. It will flow directly towards the expansion valve through the air. Since the downstream passage pressure also increases further, the main valve body maintains a stable open state.

In addition, when the pilot valve is closed from this state, the flow of refrigerant from the back pressure chamber is stopped, so the pressure in the back pressure chamber is quickly equalized with the upstream passage pressure, and the main valve body closes and expands. Co-supply of refrigerant to the valve is stopped.

〔Example] An example of the delayed opening type solenoid valve of the present invention is shown in FIG.

In the figure, l is the valve body, and an upstream passage 1b is provided in communication with the side surface of the valve chamber 1a, and a valve seat IC is provided in the bottom surface of the valve chamber 1a, which communicates with the downstream passage 1d. .

A piston-shaped main valve body 2 is slidably fitted into the valve chamber 1a, and a back pressure chamber 1e is separated from the valve chamber 1a behind the main valve body 2. The main valve body 2 is provided with a leakage passage 2a and a pressure equalization passage 2b that communicate the valve chamber 1a side and the back pressure chamber le side.

Attached to the upper part of the valve body 1 are a head body 4a and a cap body 4b, which form a low pressure chamber 4c that communicates with the downstream passage 1d through a communication pipe 3. A differential pressure valve 5 is provided which operates based on the differential pressure with the low pressure chamber 4c. Furthermore, this differential pressure valve 5 is always urged toward the main valve body 2 by a valve spring 6, and the back pressure chamber 1e and the low pressure chamber 4c are
When the differential pressure is small, the opening on the back pressure chamber Ie side of the pressure equalizing flow path 2b is pressed, and therefore the main valve body 2 is also pressed against the valve seat 1c. Note that 5a is a stopper made of an elastic material.

On the other hand, on the side of the valve body 1, there is a back pressure chamber 1e and a downstream passage 1d.
An electromagnetic pilot valve 7 is provided that can open and close a bypass flow path If communicating with the above. Note that 7a is a ball-shaped pilot valve body, 7b is a plunger, and 7c is an electromagnetic coil.

FIG. 3 shows a circuit configuration when the delayed opening solenoid valve (1) of the present invention constructed as described above is combined with an expansion valve E and an evaporative heat exchanger H of a refrigeration circuit.

In the delayed opening type solenoid valve V of the present invention, the leakage flow path 2a,
When the refrigerant flow resistances of the bypass flow path If and the pressure equalization flow path 2b are respectively A, B, and C, A>B>C.
The expansion valve E
The selection is made so that D≧B, where D is the flow resistance of the refrigerant. In a refrigeration circuit equipped with such a circuit configuration for refrigerant control, when a control signal is not input to the delayed opening solenoid valve (■), the refrigerant is controlled by filling from the upstream passage 1b to the inlet of the pilot valve 7. The refrigerant remaining in the valve V and in the downstream passage 1d is suctioned and recovered through the expansion valve E and becomes a low-pressure gas.

Here, when a control signal for the delayed opening type solenoid valve V is input from the terminal R, the pilot valve 7 opens as shown in FIG. It flows out into the downstream passage 1d while changing, but the pressure equalizing passage 2b
Since it remains open, liquid refrigerant is replenished into the back pressure chamber Le, and the pressure inside the back pressure chamber 1e does not drop much. On the other hand, since the flow resistance of the expansion valve E is greater than the flow resistance B of the bypass flow path 1f, the pressure in the downstream passage ld and therefore the pressure in the low pressure chamber 4c also gradually rises at the same time.

In this way, when the difference between the pressure in the back pressure chamber Le and the pressure in the low pressure chamber 4c gradually decreases and becomes smaller than the pressing force of the valve spring 6, the differential pressure valve 5 closes the pressure equalization flow path 2b. Then, refrigerant is supplied into the back pressure chamber Le only through the leakage flow path 2a,
Since the refrigerant rapidly flows out through the bypass flow path 1f, the pressure in the back pressure chamber Le suddenly drops. As a result, the main valve body 2 is pushed up by the pressure of the refrigerant in the valve chamber 1a against the pressing force of the valve spring 6, and the liquid refrigerant is directly supplied from the upstream passage 1b to the downstream passage 1d.

As described above, the delayed opening type solenoid valve of the present invention can alleviate the impact caused by the rush of liquid refrigerant by temporarily suppressing the amount of refrigerant supplied to the expansion valve using the refrigerant pressure. .

Furthermore, when the pilot valve 7 is closed from this state, the pressure inside the back pressure chamber 1e starts to rise due to the inflow of refrigerant from the leakage passage 2a, so the force pushing up the main valve body 2 weakens, and the pressure on the valve spring 6 is reduced. The main valve body 2 is seated on the valve seat 1c due to the pressure. Then, the pressure in the low pressure chamber 4c further decreases together with the pressure in the downstream passage, and as a result, the differential pressure valve 5 opens, and even if the pressing force of the valve spring 6 no longer works, the main valve body 2 is able to absorb the difference between the pressure in the upstream passage and the pressure in the downstream passage. The valve seat IC is pressed against the valve seat IC by the pressure, and the closed state is maintained.

[Effects of the Invention] The delayed opening type solenoid valve of the present invention is a pilot type solenoid valve in which the main valve is operated after the refrigerant pressure on the outlet side has increased to a certain extent, and in particular uses a rhythm control device. Since it is unnecessary and the circuit configuration is not complicated, the assembly of the refrigeration equipment and piping work are not only easy, efficient and economical, but also the refrigeration equipment is highly reliable and less likely to break down. There are advantages that can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of the delayed-opening solenoid valve of the present invention, showing its state when not in use, and FIG. 2 similarly showing its state during a delay period when starting its operation. FIG. 3 is a circuit diagram of an evaporative heat exchanger unit constructed using the delayed opening solenoid valve of the present invention. I... Valve body, la... Valve chamber, 1b... Upstream passage, 1C... Valve seat, 1d... Downstream passage, 1e...
Back pressure chamber, 1r... bypass flow path, 2... main valve body, 2
a...Leakage flow path, 2b...Pressure equalization flow path, 3...Connection pipe, 4a...Head body, 4b...Cap body, 4C...Low pressure chamber, 5...Differential pressure valve , 5a... Stopper, 6... Valve spring, 7... Pilot valve, 7a... Pilot valve body, 7b... Plunger, 7c... Electromagnetic coil, E
...Expansion valve, H...evaporation heat exchanger, R...terminal, ■...delayed opening type solenoid valve.

Claims (1)

[Claims] This is a pilot-type on-off valve for controlling refrigerant that is installed upstream of the expander in the refrigeration circuit via a pipe, and the leakage flow path, back pressure chamber, and bypass flow path that can be shut off by a pilot valve are connected in series in order. A control flow path is provided between the upstream passage and the downstream passage, and a main valve that opens when the resultant force of the back pressure chamber pressure and the pressing force of the valve spring is lower than the upstream passage pressure is connected between the upstream passage and the downstream passage. A differential pressure valve is provided in parallel with the control flow path between the passage and the pressure equalization flow path and is connected in series with the differential pressure valve that closes when the resultant force of the pressure in the downstream passage and the pressing force of the valve spring exceeds the pressure in the back pressure chamber. A controlled delay flow path is provided between the upstream passage and the back pressure chamber in parallel with the leakage flow path, and the leakage flow path, the bypass flow path, the pressure equalization flow path, and the flow of the refrigerant of the expander are controlled. When the resistances are A, B, C, and D, A>B>C and D≧
A delayed opening solenoid valve characterized by B.