JPS6029874B2 - Thermal response device for refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal response device for a refrigeration system that converts temperature changes into gas pressure changes and opens and closes valves via bellows.

The applicant of the present application has previously proposed, as such a thermal response device, a heat-sensitive part that senses the ambient temperature, a bellows that expands and contracts in response to the heat sensation in the heat-sensitive part, and an operation that toggles in response to the expansion and contraction of the bellows. We have proposed a device comprising a plate, and a valve mechanism and a contact mechanism that are moved and operated by the toggle action of the actuating plate.

This thermal response device detects the evaporator surface temperature or room temperature with a heat sensitive part in a general refrigeration system in which a medium compressor, a condenser, a pressure reduction mechanism, an evaporator, etc. are sequentially connected in a ring, and lowers the temperature below a predetermined temperature. When this occurs, the contact mechanism is used to stop the operation of the compressor and close the valve mechanism provided upstream of the pressure reducing mechanism to prevent cold butterflies from flowing into the evaporator. By the way, since frost forms on the surface of the evaporator, a defrost mechanism is required to remove this.

For example, in cases where the set temperature is relatively high, such as in the refrigerating compartment of a direct-cooled refrigerator-freezer, so-called cycle defrost is performed in which the defrost heater is turned on at the same time as the compressor stops operating. A changeover switch may be configured to alternately turn on and off the compressor and the defrost heater. However, when the set temperature is low, such as in a freezing room, normally only the compressor is started/stopped and the valve mechanism is opened/closed, and defrosting is forced manually or by a timer.

During this defrosting, not only the operation of the compressor must be stopped, but also the valve mechanism must be closed. However, in a thermally responsive device whose operating temperature is set low, there is a problem in that the valve mechanism opens during the process of defrosting. The present invention has been made in view of the above-mentioned points, and its purpose is to provide a refrigeration system that prevents the valve mechanism from opening until defrosting is completely completed even if the operating temperature is set low. An object of the present invention is to provide a thermal response device for equipment.

Hereinafter, the present invention will be explained by examples.

1 to 6 show an embodiment of a thermally responsive device, 1 is a heat sensitive part, and this heat sensitive part 1 is connected to a bellows 3 by a pipe 2.
It is connected to the.

The bellows 3 expands and contracts depending on the increase and decrease of internal gas pressure, and the expansion and contraction action is performed by the first actuating plate 4.
It is designed to give rotational motion to. That is, this first actuating plate 4 has side plates 5, 5' at side ends 4a, 4a'.
The upper protrusion 4b is pushed by the bellows 3 to rotate counterclockwise in FIG.
Since a clockwise rotational force is normally applied by the tension spring 8 suspended through the bellows 3 (FIG. 2), the bellows 3 returns to its original position when contracted. 9 is a screw for holding down a leaf spring 10 for preventing the screw 7 from rotating.

Further, the adjustment plate 6 is in pressure contact with the cam plate 11, and when the hollow rotating shaft 12 is rotated to rotate the cam plate 11, the adjustment plate 6 is displaced and the tension of the tension spring 8 is adjusted. It is becoming more and more common. 13 is a second operating plate;
The side ends 13a, 13a' are rotatably supported on the side plates 5, 5', and a magnet 14 is attached to the bottom surface of the tip.
A toggle plate spring 15 bent into a U-shape is attached between the V-shaped notch 13b and the tip of the first actuating plate 4 at the bottom.

In this case, as described above, the first actuating plate 4 and the second actuating plate 13
For example, when the first actuating plate 4 rotates counterclockwise in FIG.
moves clockwise and further bends, so when the first actuating plate 4 rotates to a certain angle, the second actuating plate 13 receives the elastic force of the leaf spring 15 and reverses clockwise. In this state, when the first actuating plate 4 is next rotated clockwise,
The second operating plate returns counterclockwise by the action of the leaf spring 15 similar to that described above. That is, the first actuating plate 4, the second actuating plate 13, and the leaf spring 15 constitute a toggle mechanism in which the first actuating plate 4 is an input part and the second actuating plate 13 is an output part. 16 is a screw for setting the stop position when the second actuating plate 13 rotates clockwise.

Reference numerals 17 and 18 are contacts constituting an electrical contact mechanism, and the movable contact 18 comes into contact with the fixed contact 17 when the electrically insulating push-up rod 20 rises.

This push-up bar 2 is adapted to be pushed up by its tip when the second actuating plate 13 is reversed clockwise in FIG. 21 is a piston made of magnetic material, and by moving up and down, the rod 2 at the lower end
The ball valve body 23, which is biased by the compression spring 22, is separated from the valve seat 24a of the valve case 24 by 1a.

The piston 21 is normally biased in a direction to move the ball valve body 23 away from the valve seat 24a by a compression spring 26 inscribed in a non-magnetic cap 25 placed over the top of the valve case 24. When the magnet 14 at the tip of the second actuating plate 13 comes into contact with the cap 25, the compression spring 2 receives the suction force of the magnet 14.
6, thereby raising the ball valve body 23 and closing the valve seat 24a. In other words, magnet 14, piston 21, compression spring 2
2, 26, the ball valve body 23, the valve case 24, etc. constitute a valve mechanism. 27 is an inlet, and 28 is an outlet.

3. A forced defrost operation shaft is slidably inserted into the hollow part of the rotary shaft 12, and an engagement piece 30a in the middle part operates a movable piece 31a of a microswitch 31 that functions as a forced defrost switch at one end. Each of the cams 30b is provided with a cam 30b.

This operating shaft 3 is biased in one direction by a leaf spring 32 fixed to the first actuating plate 4.
2, the end of the pond comes into contact with the first actuating plate 4 via the leaf spring 32. When the first actuating plate 4 is further pressed, the first actuating plate 4 rotates clockwise in FIGS. 1 and 2 against the tension spring 8, thereby compressing the bellows 3. . The second actuating plate 13 then rotates counterclockwise as the first actuating plate 4 rotates. 33 is formed into the shape of
The free ends of the opposing pieces 33a, 33a' are third actuating plates rotatably supported on the side plates 5, 5',
A tension spring 35 suspended between the connecting piece 33c of the third actuating plate 33 and the upright piece 6a of the extension of the adjusting plate 6 via the screw 34 normally applies a rotational force counterclockwise. An engaging roller 36 provided parallel to the connecting piece 33c is brought into elastic contact with a side surface of the engaging piece 30a of the operating shaft 30.

Therefore, when the operating shaft 30 is pressed as described above, the engagement piece 30a moves past the roller 36 and
comes to engage with the tapered engagement surface 30a' of the engagement piece 30a, and the operation shaft 301 is held at the same position. In the state shown above, the temperature of the heat sensitive part 1 is rising, the gas pressure inside the bellows 2 increases, the bellows 2 expands, and the first actuating plate 4 is pushed by the bellows 3. 1 and 2, the second actuating plate 13 is reversed clockwise, the magnet 14 is raised as shown in FIG. 24a is opened, and the movable contact 18 is pushed against the push-up rod 201 and comes into contact with the fixed contact 19.

When the temperature in the heat sensitive part 1 decreases, the internal gas pressure decreases and the bellows 3 contracts, and the first actuating plate 4 rotates clockwise in FIG. 1 due to the tensile force of the tension spring 8. As a result, the second actuating plate 13 returns counterclockwise, the magnet 14 contacts the cap 25, the piston 21 is attracted and raised, the valve seat 24a closes, and the movable contact 18 separates from the fixed contact 17.

The relationship between the above-mentioned reversal and return operation of the second operating plate 13 and the expansion and contraction operation of the bellows 3 can be adjusted by the cam plate 11.

That is, when the cam plate 11 is rotated, the tension spring 8
If the tension of changes, for example, increases the tension, then
When the gas pressure in the bellows 3 is higher than before, that is, when the temperature in the heat sensitive part 1 is high, the toggle mechanism operates to open and close the valve mechanism and the electrical contact mechanism. Conversely, if the tension of the tension spring 8 is weakened, the opening and closing described above will be performed at a low temperature. That is, the tension spring 8 to which the bellows 3 is applied
As the external pressure changes, the relationship between the gas pressure inside the bellows 3 and expansion/contraction is adjusted. Further, the adjustment screw 16 is
Among the results of adjustment by the cam plate 11, the temperature at which the second operating plate 13 returns counterclockwise as the temperature changes from high to low; that is, when the valve mechanism closes (the movable contact 18 moves away from the fixed contact 17). This is to fine-tune the temperature when leaving the room). Now, when the operation shaft 30 is pressed from the illustrated state, the tapered engagement surface 30a' of the engagement piece 30a of the operation shaft 30
'Since the roller 36 comes to engage, the operating shaft 30
A force in the thrust direction is applied to the bellows 3 by the tension spring 35, and this force is applied to the bellows 3 via the leaf spring 32 and the first operating plate 4.

At this time, in addition to this force, a force from the tension spring 8 is applied to the bellows 3, so in order to return the first actuating plate 4 to the illustrated state, it is necessary to return the first operating plate 4 to the state shown in the figure. Also, the temperature of the heat sensitive part 1 must be high and the gas pressure within the bellows 3 must be high. And heat sensitive part 1
When the temperature exceeds a predetermined value, the bellows 3 expands against the above force, and the first actuating plate 4 is rotated counterclockwise. As a result, the operating shaft 30 is also moved against the tension spring 35, so the engaging surface 30a' is disengaged from the roller 36, and the operating shaft 30 returns to the state shown. In connection with this, the microswitch 31, which was switched while the operating shaft 30 was held in the pressed state, also returns to its original state. This operation axis 3
The temperature at which the zero pressure state is released can be finely adjusted by adjusting the tension of the tension spring 35 by rotating the screw 34.

FIG. 7 shows an example of a medium circuit of a refrigeration system using the above-mentioned thermal response device, and FIG. 8 shows an example of its electric circuit.
In the refrigeration cycle consisting of 3, the valve machine side 4 of the thermal response device is inserted between the condenser 41 and the capillary tube 42, and the heat sensitive part 1 is installed near the evaporator 43, and the contact point of the thermal response device The mechanism and a forced defrost changeover switch 31' consisting of the microswitch 31 described above are connected as shown in the figure.

The changeover switch 31' has its movable contact 31 normally on the fixed contact 312 side, and the fixed contact 31 is closed during forced defrost.
Switch to the 3 side and connect the AC power supply 45 to the defrost heater 46.
It allows current to flow through. As described above, the valve mechanism 44 of the thermally responsive device is maintained in the closed state not only when the compressor 40 is stopped but also during forced defrost, thereby preventing the medium from flowing into the evaporator 43.

That is, when the operating shaft 30 is not pressed, the changeover switch 31' connects the compressor 40 to the power source 45 via the contact mechanism, so the heat sensitive section 1 of the thermal response device detects that the temperature of the evaporator 43 is at a predetermined level. When it senses that the value has increased to
The valve mechanism 44 is opened and the movable contact 18 is brought into contact with the fixed contact, the compressor 40 is operated, and cold soot is supplied to the evaporator 43.

As a result, when the temperature of the evaporator 43 falls to a predetermined value, the valve mechanism 44 closes and the operation of the compressor 40 is stopped. When the operating shaft 30 is pressed, the roller 36 is engaged with the engaging surface 30a' of the engaging piece 30a and the operating shaft is held in the pressed state, so that the valve mechanism 44 is closed and the movable contact 18 is separated from the fixed contact 17, the microswitch 31 is activated, the switch 31' is switched to the defrost heater 46 side, and defrosting of the evaporator 43 is started.

When the temperature near the evaporator 43 rises to a temperature corresponding to the end of defrosting, the internal pressure of the bellows 3 rises to an extent that overcomes the holding force of the operating shaft 30 by the spring 35 and the force of the spring 8, and the bellows 3 increases. Since it is extended, the operating shaft 30 is returned to its original position, and the first operating plate 4 is rotated clockwise. As a result, the changeover switch 31' is moved away from the defrost heater 46, the valve mechanism 44 is opened by the reversal of the second operating plate 3, and the movable contact 18 is brought into contact with the fixed contact 17, so that the defrost heater 46 is moved away from the changeover switch 31'. Simultaneously with the power supply being cut off, the operation of the compressor 40 is started, and cold soot is supplied to the evaporator 43 via the valve mechanism 44. FIG. 9 shows the opening/closing characteristics of the valve mechanism 44 and the ON/OFF of the compressor 40 by temperature sensing. In normal conditions when the defrost operating shaft 30 is not pressed, the valve mechanism 44 is opened and closed between the two lower lines. opening and closing,
The compressor 40 is turned on and off, and during forced defrost, the valve mechanism 44 is opened and the ON point of the compressor 40 is raised to the level of the upper line.

By rotating the cam plate 11 with the rotation of the rotating shaft 12 and changing the tension of the tension spring 8, the temperature at which the valve mechanism 44 is opened and closed and the compressor 40 is turned on and off can be changed as shown by the diagonal lines. In the above-described embodiments, the valve mechanism is related to a rise in temperature, but by configuring the valve mechanism as shown in FIG. 10, it is also possible to close the valve mechanism due to a rise in temperature. The configuration shown in FIG. 10 will be explained below.

Note that the same reference numerals as in FIGS. 1 to 6 indicate the same members, and explanations thereof will be omitted. It is a valve body made of a 50G magnetic material, and opens and closes between the inlet 27 and the outlet 28 by moving up and down. The valve body 50' is housed in the valve case 52 by a non-magnetic cap 51, and is normally closed by a compression spring 53 to close the valve seat 52a. 14 comes into contact with the cap 51, receives the attraction force of the magnet 14, rises against the force of the compression spring 53, and opens the valve seat 52a. As is clear from the above embodiments, the thermally responsive device according to the present invention selectively applies a certain contracting force to the bellows through the actuating plate that operates the valve mechanism and the contact mechanism, and changes the state of the bellows by thermosensitive. The valve mechanism is held in a state where it does not operate until the heat sensitivity in the valve reaches a predetermined temperature or higher, so if defrost is performed in this state, the valve mechanism can be maintained in a state where it does not operate until the defrost is completed. It becomes like this.

Therefore, it is possible to obtain a thermally responsive device that can be applied to, for example, a refrigeration system in which the valve mechanism opens during defrost.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a thermally responsive device according to an embodiment of the present invention, and FIG.
The figure is a cross-sectional view of a part of the plane different from that in Figure 1.
The figure is a partial plan view of the device with the bellows removed, FIG. 4 is a partially cut-away left side view of the same device, FIG. 5 is a partially cut-away right side view of the same device, and FIG. 6 is a partially cut-away right side view of the same device. 7 is a cold soot circuit diagram of a refrigeration system using the same device, FIG. 8 is an electric circuit diagram of the refrigeration system, FIG. 9 is a characteristic diagram of the refrigeration system, and FIG. 10 is a sectional view of another embodiment. 1... Heat sensitive part, 3... Bellows, 4... Operating plate, 17... Fixed contact, 18... Movable contact,
23... Valve body, 24a... Valve seat, 30...
...Defrost operation shaft, 30a...Engagement piece, 3
5...Tensile spring, 36...Loaf o No. 1〆Fig. 2 Fig. 4 Fig. 5 Fig. 6 and 7* Fig. 8 Fig. 9 Fig. ○

Claims (1)

[Claims] 1. A heat-sensitive part provided near the evaporator to sense the temperature of that part, a bellows that expands and contracts in response to heat sensitivity in the heat-sensitive part, and a first actuating plate that applies a first contraction force to the bellows. a second actuation plate that toggles in response to displacement of the first actuation plate due to expansion and contraction of the bellows; a valve mechanism and a contact mechanism that operate in conjunction with each other by the toggle action of the second actuation plate; In a thermal response device, the valve mechanism controls the opening and closing of the refrigerant flow path, and the contact mechanism controls the start and stop of the compressor. A thermally responsive device further comprising: means for applying force additively; and means for maintaining the state in which the contraction force is applied until the heat sensitivity at the heat-sensitive portion reaches a predetermined temperature or higher.