JPS5821960Y2 - Supercooling control valve - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a subcooling control valve that controls the degree of subcooling of refrigerant on the outlet side of a condenser in a refrigeration system and supplies an appropriate amount of refrigerant to an evaporator.

The industrial field in which it is used is general refrigeration and cooling equipment, which is continuously used under conditions where the ambient temperature fluctuates widely, such as in summer and winter.

For example, it is applied to air-cooled package air conditioners, chillers, etc.

The supercooling control valve detects the degree of supercooling of the refrigerant on the condenser outlet side of the refrigeration cycle, and compares it with the set degree of supercooling to supply an appropriate amount of refrigerant to the evaporator, and adiabatically expands the high-pressure refrigerant through the throttle hole. This is a valve that acts to reduce pressure, and the refrigerant pressure P' of the temperature sensing part that detects the temperature on the condenser outlet side is introduced into the chamber above the diaphragm of the power element chamber at the head of the valve body, and the condenser outlet pressure (- Next side pressure) Pl is introduced into the diaphragm lower chamber, and the set tension P3 of the supercooling degree setting spring provided in the secondary side chamber is applied to the diaphragm, and the pressure difference P'P1 acting on the diaphragm effective area A and , spring tension P
3 to open and close the valve.

Therefore, in a valve having this structure, the refrigerant sealed in the temperature sensing section is a refrigerant that has a higher relative pressure than the device refrigerant at the same temperature.

As an example, US Pat. No. 3,367,130 discloses a device in which R-143a or R-502 is encapsulated as a temperature-sensing refrigerant in place of the device refrigerant R-22.

To explain with the diagram in Figure 2, which compares the condensing pressure and temperature characteristic curves (PT curves) of R-143a and R-22,
Curve A shows the P-T curve of R-22, and curve opening ' shows R-22's P-T curve.
The P-T curve of R-143a is shown, and the curve opening is the set tension P3 of the spring from the pressure value P' of the P//T curve of R-143a.
This figure shows a valve opening point characteristic curve expressed as P'-p3 after subtracting P'-p3.

Comparing A and A, the temperature difference (degree of supercooling) for the same pressure is almost the same in the range of high condensing pressure and the range of low condensing pressure, and the valve operates at the same degree of supercooling.

This is the P-
This is because the slope of the T curve (dp/dt) and the slope of the P'-T curve (dp/dt) of the sealed refrigerant R-143a are almost the same.

Figure 3 is a diagram comparing the PT curves of R-502 and R-22, where A is the PT curve of R-22, C' is the PT curve of R-502, and C is the valve opening point. Comparing the characteristic curves A and 8, the degree of supercooling is small in the range of high condensing pressure, and the degree of supercooling is large in the range of low condensing pressure.

This is based on the slope dp/dt of the PT curve of the device refrigerant.
The slope dp/dt of the P'-T curve of the sealed refrigerant is small (d
p/〉dp'/dt).

t When these supercooling control valves are used in water-cooled refrigeration equipment, the condensing pressure hardly changes throughout the year, so the degree of supercooling does not change and a stable flow rate can be controlled. Most air-conditioning systems are air-cooled, and in these air-cooled refrigeration systems, the condensing pressure changes significantly depending on fluctuations in the surrounding outside air temperature, and the condensing pressure in summer can reach several times that in winter, and the The flow rate relative to the degree of supercooling is excessive in summer compared to winter, and conversely, in winter when the ambient temperature is low and condensing pressure is low, the flow rate is low and the cooling capacity is reduced. The problem arose that it had to be done.

As is clear from the above explanation, the slope d of the P′-T curve of the sealed refrigerant is
It is understood that by setting V<dp;/dt, it is possible to compensate for changes in flow rate due to changes in condensing pressure due to changes in ambient t temperature.

Therefore, the present invention has developed the characteristics of the slope dp/ of the P'-T curve of the refrigerant enclosed in the temperature sensitive section, t is dp/, and t dp/dt with respect to the slope dp/ of the P-T curve of the device refrigerant R-22. The technical challenge is to make this possible.

In order to solve the above technical problems, the technical measures taken by the present invention are as follows.

The refrigerant enclosed in the temperature sensing part of the supercooling control valve is monopromotofluoromethane (R-13B1).

The above technical means works as follows.

Figure 4 shows the P-T curve and valve opening point characteristic curve of R-13B1 and R-22. Curve A shows the P-T curve of R-22.
-T curve, curve 2' shows the PT curve of R-13B1, and curve 2 shows the valve opening point characteristic curve.

The sealed refrigerant pressure P' of the temperature sensing part is introduced into the upper chamber of the diaphragm, the condenser outlet pressure P1 is introduced into the lower chamber of the diaphragm, and the pressure difference (P'P1) acting on the diaphragm effective area A and the secondary side chamber are The opening and closing of the valve is controlled by opposing the set tension P3 of the provided supercooling degree setting spring, but as shown in Fig. 4, dp
, ;/dt > dp/dt When the condensing pressure is low, the valve starts to open at a small degree of supercooling, and when the condensing pressure is high, the valve starts to open at a large degree of supercooling. In the operating state of the equipment and in the pressure range where the condensing pressure is high, the valve will not begin to open unless the degree of supercooling becomes large, but even if the valve opening is small, the difference in refrigerant pressure before and after the valve is large, so the flow rate cannot be secured. In the low pressure range, the degree of supercooling is small and the valve begins to open, so in the degree of supercooling in the low pressure range, which corresponds to the degree of supercooling at the beginning of the valve opening in the high pressure range, the degree of valve opening is sufficiently large, and the refrigerant before and after the valve is Since a flow rate can be ensured even if the pressure difference is small, a predetermined flow rate can be obtained even if the condensing pressure changes due to fluctuations in ambient temperature.

The present invention produces the following unique effects.

Hunting phenomenon during valve opening/closing operation is reduced.

This is based on the slope dp/dt of the PT curve of the device refrigerant.
Since the gradient dp;/dt of the refrigerant sealed in the temperature sensing part of the control valve is large, the refrigerant pressure with respect to temperature is higher than the pressure of the device refrigerant, and the pressure of the refrigerant sealed in the temperature sensing part is higher than that of the conventional temperature sensing part. The valve opening/closing operation is stabilized because the set tension P3 of the supercooling degree setting spring that counters the (P'-P)A load, which is the difference between the hot part sealed refrigerant pressure and the device refrigerant pressure multiplied by the effective area of the diaphragm, becomes larger. It turns out.

The illustrated embodiment will be described below to show a specific example of the technical means of the present invention.

Figure 1 shows a cross-sectional view of the supercooling control valve from →q.
The sealed gas pressure P' of the temperature sensing cylinder 1, which is installed between the condenser and the evaporator of the refrigeration system and detects the temperature of the condenser outlet side piping, is introduced into the upper surface of the diaphragm 6, and the condensation of the device refrigerant is introduced into the lower surface of the diaphragm. Pressure P and gold 1. Connecting rod9. Earth spring holder 1
3, the elastic force P3 of the adjustment spring 18 acts.

There is a screw 15 on the upper spring holder that adjusts the opening degree of the needle valve 10.
However, a small spring 11 is provided above the needle valve so as to be able to come into contact with and separate from the iron that extends integrally below the needle valve. The screw engagement of the spring receiver 14 is adjusted to set the elasticity P3 corresponding to a predetermined degree of supercooling.

When the combined force of the condensation pressure P1 of the refrigerant and the elasticity P3 of the spring 18 is balanced against the gas pressure P' at the surface of the diaphragm at a predetermined degree of supercooling of the device refrigerant, the needle valve just closes the valve hole. The position of the needle valve is adjusted using an adjustment screw 15 so that it is closed.

Therefore, when the degree of supercooling of the apparatus refrigerant becomes greater than the set value, P' is reduced in pressure and the valve 10 opens, and when the degree of supercooling decreases below the set value, the valve acts in the closing direction to maintain the degree of supercooling at the set value. It works like this.

In Figure 4, when looking at curves A and 2 in combination, the device refrigerant R
-22 saturation pressure 21 alarm G at 55℃ is R-13B
This corresponds to the saturation pressure of 147.5°C, and the valve begins to open when the degree of supercooling of R-22 is 7°5°.

This shows that when R-22 is at a temperature of 30°C, the valve starts to open at a degree of supercooling of 3 degrees.

Therefore, R-13B1 is used as the gas sealed in the thermosensor tube 1.
If you select R-22, the degree of supercooling that causes the valve to open in the high temperature range will be small in the low temperature range, and even if the pressure difference between the high and low pressures of the device refrigerant becomes small at low temperatures, the degree of supercooling that will cause the valve to open will be small. The required refrigerant flow rate can be obtained because the valve opens at a certain degree, and in the supertemperature range, the valve will not open unless the degree of supercooling becomes large, but even when the valve opening is small, the difference in refrigerant high and low pressures is large. This has the advantage that a predetermined flow rate can be obtained and a substantially constant flow rate of refrigerant can be supplied regardless of whether the temperature is high or low.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an example of a supercooling control valve, Figure 2 is an R-
A diagram comparing the PT curves of 143a and R-22. Figure 3 is a diagram comparing the P-T curves of R-502 and R-22, and Figure 4 is a diagram comparing the P-T curves of R-502 and R-22.
A line diagram that contrasts curves. This is what is shown. 1... Temperature sensing tube, 2... Capillary tube, 4... Upper lid, 5... Lower lid, 6...
...Diaphragm, 7...Okine, 8...
・Valve body, 9...Connecting rod, 10...Needle valve, 13...Upper spring holder, 14...
・Lower spring holder, 15...adjustment screw, 11...
...Small spring, 18...Adjustment spring.

Claims (1)

[Scope of utility model registration request] A supercooling control valve for a refrigeration system in which monochlorodifluoromethane (R-22) is used as the device refrigerant, and monopromotrifluoromethane (R-13B) is used as the refrigerant sealed in the temperature sensing part of the supercooling control valve.