JP2023161664A - Frozen confectionery manufacturing apparatus - Google Patents

Abstract

To accurately adjust the temperature of a raw material cooled by an evaporator as compared with a case in which control is executed based only on a load when agitating a raw material.SOLUTION: A frozen confectionery manufacturing apparatus includes: a compressor for compressing a cooling medium; a condenser for condensing the cooling medium compressed by the compressor; an expansion valve for expanding the cooling medium condensed by the condenser; an evaporator for exchanging heat between the cooling medium expanded by the expansion valve and a raw material of frozen confectionery, cooling the raw material, and evaporating the cooling medium; a detection part for detecting evaporation pressure of the cooling medium in a gaseous state evaporated by the evaporator; and a control device for controlling a state of the cooling medium in the evaporator on the basis of a result of the detection by the detection part.SELECTED DRAWING: Figure 3

Description

The present invention relates to a frozen dessert manufacturing apparatus.

As a prior art, Patent Document 1 discloses a refrigerator in which a compressor, a radiator, an expansion valve, and an evaporator are connected in this order by refrigerant piping.

Japanese Patent Application Publication No. 2016-090103

In a frozen dessert manufacturing apparatus that cools raw materials for frozen desserts using an evaporator, for example, the load when stirring the raw materials for frozen desserts may be detected, and the state of the refrigerant in the evaporator may be controlled based on the detection result. However, the load when stirring the raw material changes slowly compared to the temperature of the raw material, and even if the state of the refrigerant in the evaporator is controlled based on the load when stirring the raw material, the evaporator It was difficult to accurately adjust the temperature of the material being cooled.
An object of the present invention is to more accurately adjust the temperature of the raw material cooled by the evaporator, compared to the case where control is performed only based on the load when stirring the raw material.

The present invention, which was completed with such an objective, comprises a compressor for compressing refrigerant, a condenser for condensing the refrigerant compressed by the compressor, and an expansion valve for expanding the refrigerant condensed by the condenser. , an evaporator that performs heat exchange between the refrigerant expanded by the expansion valve and the raw material for the frozen dessert to cool the raw material and evaporate the refrigerant; and evaporation of the gaseous refrigerant evaporated in the evaporator. The frozen dessert manufacturing apparatus includes a detection section that detects pressure, and a control device that controls the state (pressure) of refrigerant in the evaporator based on the detection result by the detection section.
Here, the control device may control the state of the refrigerant in the evaporator so that the evaporation pressure becomes a predetermined set pressure.
In addition, the control device adjusts the operating frequency of the compressor or the amount of high-temperature gaseous refrigerant discharged from the compressor supplied to the evaporator (hot gas amount), thereby controlling the amount of gas inside the evaporator. The state of the refrigerant may be controlled.
Further, carbon dioxide may be used as the refrigerant.

According to the present invention, the temperature of the raw material cooled by the evaporator can be adjusted more accurately than when control is performed based only on the load when stirring the raw material.

1 is a diagram illustrating an example of a schematic configuration of a frozen dessert manufacturing apparatus to which this embodiment is applied. (a) to (b) are diagrams showing an example of the configuration of a stirring device to which this embodiment is applied. FIG. 2 is a diagram showing an example of a schematic configuration of a control device. It is a flowchart which shows an example of the frequency change process performed by a compressor control part. It is a flowchart which shows an example of the opening degree change process of the hot gas valve performed by a hot gas control part.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a diagram showing an example of a schematic configuration of a frozen dessert manufacturing apparatus 1 to which this embodiment is applied.
The frozen dessert manufacturing apparatus 1 is used to manufacture frozen desserts such as ice cream and frozen desserts. The frozen dessert manufacturing apparatus 1 of this embodiment includes a stirring device 100 that stirs and cools a raw material mix that is a mixture of frozen dessert raw materials and air. Note that the configuration of the stirring device 100 will be described in detail later.

The frozen dessert manufacturing apparatus 1 includes a compressor 2, a condenser 3, an expansion valve 4, an evaporator 5, an accumulator 6, a heat exchanger 7, and a liquid receiver 8, as shown in FIG. The frozen dessert manufacturing apparatus 1 also has an annular refrigerant circuit 51 connecting a compressor 2, a condenser 3, an expansion valve 4, an evaporator 5, an accumulator 6, a heat exchanger 7, a liquid receiver 8, etc. .
The frozen dessert manufacturing apparatus 1 uses carbon dioxide refrigerant (hereinafter sometimes referred to as "CO ₂ refrigerant") as a refrigerant. CO ₂ refrigerant has a lower global warming potential than fluorocarbon refrigerants. By using CO ₂ refrigerant, the frozen dessert manufacturing apparatus 1 aims to reduce the environmental load more than an apparatus using other refrigerants.

Furthermore, the frozen dessert manufacturing apparatus 1 includes a branch line 52 that branches from the pipe between the compressor 2 and the condenser 3 in the refrigerant circuit 51 and has a terminal end connected to the evaporator 5 .
In addition, in the frozen dessert manufacturing apparatus 1, a high-temperature, high-pressure gaseous refrigerant (hereinafter sometimes referred to as "hot gas") compressed by the compressor 2 is supplied to the evaporator 5 on the branch path 52. A hot gas valve 9 is provided to adjust the amount of inflow (hot gas amount).
The frozen dessert manufacturing apparatus 1 also includes a well-known separator 11 that separates oil for lubricating the compressor 2 from the refrigerant flowing out from the compressor 2, and a well-known separator 11 that separates oil from the separator 11 into the compressor 2. A well-known return unit 12 is provided for return.
The frozen dessert manufacturing apparatus 1 also includes an oil supply device 20 that supplies oil into the refrigerant flowing into the compressor 2.

Furthermore, the frozen dessert manufacturing apparatus 1 includes an evaporation pressure sensor 31 that detects the pressure of the gaseous refrigerant in the accumulator 6, and a liquid level sensor 32 that detects the height of the liquid refrigerant in the evaporator 5. and a liquid receiver pressure sensor 33 that detects the pressure of the refrigerant in the liquid receiver 8.
Furthermore, the frozen dessert manufacturing apparatus 1 releases the refrigerant to the outside of the frozen dessert manufacturing apparatus 1 when the pressure of the refrigerant in the evaporator 5 and the accumulator 6 exceeds a predetermined upper limit as measured by the evaporation pressure sensor 31. A high pressure side that releases the refrigerant to the outside of the frozen dessert manufacturing apparatus 1 when the pressure of the refrigerant in the liquid receiver 8 measured by the low pressure side safety valve 35 and the liquid receiver pressure sensor 33 exceeds a predetermined upper limit value. A safety valve 36 is provided.
Further, the frozen dessert manufacturing apparatus 1 includes a control device 60 that controls each part of the frozen dessert manufacturing apparatus 1.
Below, the elements constituting the frozen dessert manufacturing apparatus 1 will be explained in more detail.

The compressor 2 sucks refrigerant through a suction section 2a, compresses it, and discharges it from a discharge section 2b. Thereby, the compressor 2 circulates the refrigerant within the refrigerant circuit 51. The compressor 2 has a motor 2c as a driving source, and the operating frequency is continuously adjusted by controlling the motor 2c by the control device 60. Examples of the compressor 2 include a so-called rotary compressor that compresses refrigerant by rotating a piston with a motor 2c, a so-called reciprocating compressor that compresses refrigerant by reciprocating a piston with a motor 2c, etc. , but is not particularly limited. In addition, the operating frequency of the compressor 2 means the number of times (number of rotations, number of reciprocations) that a moving body such as a piston driven by the motor 2c moves per unit time (for example, 1 second) in the compressor 2. do.

The condenser 3 condenses and liquefies the refrigerant compressed by the compressor 2 by exchanging heat with chiller water cooled to a predetermined temperature by a cooling device (not shown). In this embodiment, since CO ₂ refrigerant is used, which has a higher pressure in the gaseous state than fluorocarbon-based refrigerants, chilled water is used as chiller water in order to further cool the refrigerant discharged from the compressor 2. Use. The device that generates chilled water and the device that supplies chilled water to the condenser 3 may be located within the frozen dessert manufacturing device 1 or may be provided separately from the frozen dessert manufacturing device 1. FIG. 1 shows an example in which a device for generating chilled water and a device for supplying chilled water to a condenser 3 are provided separately from the frozen dessert manufacturing device 1.

The expansion valve 4 decompresses and expands the refrigerant condensed in the condenser 3. The expansion valve 4 of this embodiment is a so-called motor valve that includes a valve (not shown) that opens and closes a flow path through which a refrigerant flows, and a motor 4a that drives the valve to open and close. Based on the control by the control device 60, the motor 4a is driven and the valve is rotated, so that the rotation angle (hereinafter sometimes referred to as "opening degree") of the valve is adjusted, and the refrigerant is circulated. The possible flow area is changed. Note that when the valve opening is 0 degrees, the valve is fully closed and the flow path area is 0, and when the valve opening is at the maximum opening, the valve is fully open and the flow path area is 0. is the maximum. The opening degree of the valve is continuously adjusted between 0 degrees and the maximum opening degree. Thereby, the amount of refrigerant that passes through the expansion valve 4 and is supplied to the evaporator 5 is continuously adjusted.

The evaporator 5 is provided outside the stirring device 100 described above. The evaporator 5 evaporates the refrigerant expanded by the expansion valve 4 by exchanging heat with a frozen dessert raw material mix supplied to a cylinder inner tube 110 (described later) of the stirring device 100. In addition, in the stirring device 100, the raw material mix is cooled by the refrigerant in the evaporator 5, and a frozen dessert is manufactured.
The accumulator 6 separates the gaseous refrigerant evaporated in the evaporator 5 from the liquid refrigerant. Then, the accumulator 6 returns the separated liquid refrigerant to the evaporator 5 and prevents the liquid refrigerant from flowing into the compressor 2.

The heat exchanger 7 performs heat exchange between the refrigerant that has been evaporated in the evaporator 5 and passed through the accumulator 6 and the refrigerant that has been condensed in the condenser 3 and discharged from the receiver 8 . In addition, the heat exchanger 7 heats the refrigerant that has passed through the accumulator 6 with the high-temperature refrigerant discharged from the liquid receiver 8, and if liquid refrigerant remains in the refrigerant that has passed through the accumulator 6, The remaining liquid refrigerant is vaporized to prevent the liquid refrigerant from flowing into the compressor 2.
The liquid receiver 8 stores a portion of the liquid refrigerant condensed in the condenser 3 and supplies the stored refrigerant to the expansion valve 4 .

The hot gas valve 9 supplies the hot gas discharged from the compressor 2 to the evaporator 5 via the branch path 52. The hot gas valve 9 has a motor 9a that drives the valve to open and close. The opening degree of the hot gas valve 9 is continuously adjusted based on the control of the motor 9a by the control device 60. Thereby, the flow rate of hot gas supplied to the evaporator 5 is continuously adjusted by the hot gas valve 9.

The evaporation pressure sensor 31 is an example of a detection unit, and detects the pressure of the gaseous refrigerant in the evaporator 5 and the accumulator 6 by detecting the pressure in the pipe between the accumulator 6 and the low-pressure side safety valve 35. do.
The liquid receiver pressure sensor 33 detects the pressure of the gaseous refrigerant in which the liquid refrigerant in the liquid receiver 8 is vaporized by detecting the pressure in the pipe between the liquid receiver 8 and the high-pressure side safety valve 36. Detect.

The liquid level sensor 32 measures the height of the liquid refrigerant in the evaporator 5 in a space S2 between the cylinder inner cylinder 110 and the cylinder outer cylinder 120 (both shown in FIG. Detect the height of the refrigerant liquid level in (a) to (b)). The liquid level sensor 32 is not particularly limited as long as it can continuously detect the height of the refrigerant liquid level, but for example, a capacitive liquid level sensor can be used.
The detection result by the liquid level sensor 32 is output to the control device 60.

Next, the behavior of the refrigerant in the frozen dessert manufacturing apparatus 1 of this embodiment will be explained. In the frozen dessert manufacturing apparatus 1 of the present embodiment, the refrigerant is supplied to the compressor 2, the condenser 3, the liquid receiver 8, the separation heat exchanger 22 (described later), the heat exchanger 7, the expansion valve 4, the evaporator 5, and the accumulator. 6. A refrigeration cycle is constructed in which the water flows through the heat exchanger 7 in order and returns to the compressor 2.
Specifically, in the frozen dessert manufacturing apparatus 1, a high-temperature, high-pressure gaseous refrigerant compressed by the compressor 2 and discharged from the discharge portion 2b flows into the condenser 3. Then, in the condenser 3, the refrigerant exchanges heat with chiller water cooled to a predetermined temperature, is condensed and liquefied, and is discharged from the condenser 3. The high-pressure liquid refrigerant discharged from the condenser 3 passes through the receiver 8 , the separation heat exchanger 22 , and the heat exchanger 7 . Note that the refrigerant flowing from the receiver 8 to the heat exchanger 7 is used to heat the refrigerant flowing from the accumulator 6 to the compressor 2. Next, the high-pressure liquid refrigerant discharged from the heat exchanger 7 is depressurized by the expansion valve 4 and enters the evaporator 5 after becoming in a gas-liquid two-phase state. The refrigerant then undergoes heat exchange with the raw material mix in the evaporator 5, is evaporated, and is discharged from the evaporator 5. The low-pressure gaseous refrigerant discharged from the evaporator 5 passes through the accumulator 6 and the heat exchanger 7, and then is sucked into the compressor 2 through the suction section 2a and compressed again.

In addition, in the frozen dessert manufacturing apparatus 1, the high temperature and high pressure gaseous refrigerant (hot gas) compressed by the compressor 2 and discharged from the discharge part 2b passes through the branch path 52 and is supplied to the hot gas valve 9. . Then, when predetermined conditions are met, hot gas is directly supplied to the evaporator 5 by the hot gas valve 9.

(Agitator 100)
Next, the configuration of the stirring device 100 will be explained. FIGS. 2(a) to 2(b) are diagrams showing an example of the configuration of a stirring device 100 to which this embodiment is applied. FIG. 2(a) is a side view of the stirring device 100, and FIG. 2(b) is a sectional view taken along the line IIB-IIB in FIG. 2(a).
As shown in FIGS. 2(a) and 2(b), the stirring device 100 is provided with a cylindrical inner cylinder 110 to which a raw material mix for frozen dessert is supplied, and an outer side of the cylinder inner cylinder 110. and a cylindrical outer cylinder 120 into which a refrigerant is supplied to the space formed between the two. The stirring device 100 also includes a stirring section 130 that is provided in the inner space of the cylinder inner tube 110 and stirs the raw material mix supplied to the inner space of the cylinder inner tube 110.

In the frozen dessert manufacturing apparatus 1 of this embodiment, the above-mentioned evaporator 5 is configured by the cylinder inner tube 110 and the cylinder outer tube 120 of the stirring device 100.
Furthermore, in the stirring device 100 of this embodiment, the cylinder inner tube 110 and the cylinder outer tube 120 are arranged so that their central axes are substantially horizontal.

As described above, the raw material mix is supplied to the internal space S1 of the cylinder inner cylinder 110. Then, in the cylinder inner tube 110, the raw material mix is stirred and cooled in the space S1, thereby producing a frozen dessert as a finished product.
The cylinder inner cylinder 110 has a raw material supply port 111 provided at one end in the axial direction, through which the raw material mix is supplied toward the space S1, and a raw material supply port 111 provided at the other end in the axial direction, through which the manufactured frozen dessert is supplied. It has a frozen dessert outlet 112 which is discharged from the space S1. The raw material mix is stored in a raw material tank (not shown), and is supplied to the space S1 via the raw material supply port 111 by a raw material supply pump. Further, the frozen dessert manufactured in the space S1 is discharged from the space S1 to a frozen dessert tank (not shown) via the frozen dessert outlet 112 while keeping the pressure in the cylinder inner tube 110 constant by a discharge pump.

Further, the cylinder inner cylinder 110 has a raw material temperature sensor 114 that measures the temperature of the raw material mix supplied to the raw material supply port 111. Further, the cylinder inner tube 110 has a frozen dessert temperature sensor 115 that measures the temperature of the frozen dessert discharged from the frozen dessert outlet 112. The temperature measurement results by the raw material temperature sensor 114 and the frozen dessert temperature sensor 115 are output to the control device 60 (see FIG. 1).

As described above, the cylinder outer cylinder 120 is arranged outside the cylinder inner cylinder 110, and is expanded into the space S2 formed between the cylinder inner cylinder 110 and the outer peripheral surface thereof by the expansion valve 4 (see FIG. 1). A low temperature, low pressure liquid refrigerant is supplied. In the cylinder outer cylinder 120, the refrigerant is supplied such that, for example, the liquid level of the refrigerant is higher than the vertical upper part of the outer circumferential surface of the cylinder inner cylinder 110. Then, in the cylinder outer cylinder 120, heat exchange is performed between this refrigerant and the raw material mix supplied to the space S1 of the cylinder inner cylinder 110, and the refrigerant is evaporated.

Here, in the stirring device 100 of the present embodiment, the center axis of the cylinder inner tube 110 and the center axis of the cylinder outer tube 120 are arranged to be shifted from each other. Specifically, as shown in FIG. 2(b), the center axis of the cylinder inner tube 110 is arranged vertically shifted downward with respect to the center axis of the cylinder outer tube 120. This reduces the amount of refrigerant required to cool the cylinder inner cylinder 110 compared to, for example, the case where the central axis of the cylinder inner cylinder 110 and the central axis of the cylinder outer cylinder 120 coincide. It is possible to widen the evaporation area and perform efficient heat exchange.

The cylinder outer cylinder 120 has a refrigerant supply port 121 through which the low-temperature, low-pressure liquid refrigerant expanded by the expansion valve 4 is supplied toward the space S2, and a refrigerant discharge port through which the gaseous refrigerant evaporated by heat exchange is discharged. 122. The refrigerant discharged from the refrigerant outlet 122 flows into the accumulator 6 (see FIG. 1). Furthermore, the cylinder outer cylinder 120 has a hot gas supply port 123 through which high-temperature gaseous refrigerant (hot gas) is supplied toward the space S2 by the hot gas valve 9. Furthermore, the cylinder outer cylinder 120 has a refrigerant suction port 124 through which liquid refrigerant is sucked into the oil supply device 20 .

The refrigerant supply port 121 , the refrigerant discharge port 122 , the hot gas supply port 123 , and the refrigerant suction port 124 are provided on the outer peripheral surface of the cylinder outer tube 120 . In this example, the refrigerant supply port 121 is provided vertically below the outer peripheral surface of the cylinder outer tube 120. Furthermore, two refrigerant discharge ports 122 are provided vertically above the outer circumferential surface of the cylinder outer tube 120. Furthermore, the hot gas supply port 123 is provided in the center of the cylinder outer cylinder 120 on the outer peripheral surface of the cylinder outer cylinder 120. Furthermore, the refrigerant suction port 124 is provided vertically above the refrigerant supply port 121 and in the center of the cylinder outer cylinder 120 .

As described above, the stirring section 130 stirs the raw material mix supplied to the space S1 within the cylinder inner tube 110. The stirring section 130 includes a cylindrical support section 131 that extends along the axial direction in the space S1 within the cylinder inner tube 110, and a plurality of blades 132 provided on the outer peripheral surface of the support section 131. The stirring section 130 also includes a rotating shaft 133 that extends along the axial direction from one end and the other end of the support section 131 and is rotatably supported at both ends of the cylinder inner tube 110 via bearings 139. have. Further, the stirring section 130 includes a motor 135 that rotates the rotating shaft 133 at a predetermined rotation speed under the control of the control device 60, and an inverter 136 that detects the rotational load on the rotating shaft 133 caused by the motor 135. are doing.
Here, in the stirring device 100 of the present embodiment, the central axis of the stirring section 130 and the central axis of the cylinder inner tube 110 are arranged so as to substantially coincide with each other. In addition, in the stirring device 100, the stirring portion 130 is arranged approximately at the center of the cylinder inner tube 110.

In the agitating section 130, the rotating shaft 133 is rotationally driven by the motor 135, so that the supporting section 131 and the blade 132 rotate in the space S1 within the cylinder inner tube 110. Then, in the space S1, the raw material mix is stirred while the blade 132 scrapes off the deposits adhering to the inner wall surface of the cylinder inner tube 110.

(Oil supply device 20)
The oil supply device 20 supplies oil into the refrigerant flowing into the compressor 2. Here, since the refrigerant used in the frozen dessert manufacturing apparatus 1 is a CO ₂ refrigerant, in the temperature range when it exists in the space S2, the oil completely dissolves into the refrigerant, and the oil and refrigerant are separated. It has the characteristic of being difficult to separate. Moreover, if the amount of oil contained in the refrigerant in the space S2 is large, there is a possibility that heat exchange between the refrigerant containing a large amount of oil and the raw material mix in the cylinder inner tube 110 will be inhibited.
The oil supply device 20 is provided in the frozen dessert manufacturing device 1 in view of the above-mentioned matters, and pulls the refrigerant in the space S2 out of the cylinder outer cylinder 120 in a state in which oil is mixed therein, and also draws out the refrigerant and the oil. and the oil is supplied into the refrigerant flowing into the compressor 2.

The oil supply device 20 includes an ejector 21 that sucks the refrigerant from the space S2, and a separation heat exchanger 22 that separates the refrigerant (containing oil) sucked by the ejector 21 from oil and the refrigerant. have. The oil supply device 20 has a secondary branch path 54 that branches from the upstream side of the hot gas valve 9 in the branch path 52 and has a terminal end connected to the ejector 21 . The oil supply device 20 also includes a suction path 55 that connects the space S2 and the ejector 21 and allows the refrigerant in the space S2 to flow toward the ejector 21. The oil supply device 20 also has an inflow path 56 that connects the ejector 21 and the separation heat exchanger 22 and causes the refrigerant flowing out from the ejector 21 to flow into the separation heat exchanger 22. The oil supply device 20 also connects the separation heat exchanger 22 and a pipe 57 between the heat exchanger 7 and the compressor 2, and directs the refrigerant flowing out from the separation heat exchanger 22 to the pipe 57. It has an outflow path 58 for inflow.

The ejector 21 has a nozzle part 21a through which the refrigerant made high-pressure by the compressor 2 passes, and a suction part 21b that sucks the refrigerant in the space S2. In this ejector 21, the refrigerant made high-pressure by the compressor 2 flows in from the inlet of the nozzle portion 21a, is depressurized and expanded as the flow path area decreases, and flows out after increasing the flow velocity. On the other hand, the refrigerant in the cylinder outer cylinder 120 is sucked from the inlet of the suction part 21b due to the pressure difference between the inlet of the suction part 21b and the nozzle part 21a, and the refrigerant is made into high pressure by the compressor 2. The two refrigerants are mixed and flow out from the ejector 21. The behavior of the refrigerant in the ejector 21 utilizes the Venturi effect.

The refrigerant flowing out from the ejector 21 exchanges heat with the high-pressure liquid refrigerant that has been condensed in the condenser 3 in the separation heat exchanger 22, and is vaporized. As a result, the refrigerant and the oil are separated, and the separated oil flows into the pipe 57 disposed upstream of the compressor 2 via the outflow path 58. In this way, oil is extracted from the refrigerant in the space S2 and is injected into the gaseous refrigerant upstream of the compressor 2.

(Control device 60)
FIG. 3 is a diagram showing an example of a schematic configuration of the control device 60.
The control device 60 includes a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) (not shown), a RAM (Random Access Memory) (not shown), and the like. The ROM stores a basic program (operation system) executed by the CPU, various settings, and the like. The CPU uses RAM as a work area and executes application programs read from a storage unit (not shown) such as a ROM, semiconductor memory, or HDD (Hard Disk Drive). When the CPU executes the program, the functions of the control device 60 described below are realized.

Output signals from the above-mentioned evaporation pressure sensor 31, liquid level sensor 32, etc. are input to the control device 60.
The control device 60 includes a compressor control section 61 as an example of a control section that controls a frequency F, which is the operating frequency of the compressor 2, and a hot gas supply section as an example of a hot gas supply section that controls the opening degree of the hot gas valve 9. It includes a control section 62 and an expansion valve control section 63 that controls the opening degree of the expansion valve 4.

In the control device 60, the raw material supply pump is started to store the raw material mix in the cylinder inner tube 110, and the stirring device 100 is started. Thereafter, the compressor 2 is started at a predetermined frequency, and the hot gas valve 9 is opened to a predetermined opening degree. As a result, the temperature of the raw material mix in the cylinder inner tube 110 decreases and hardening begins. When the motor load of the stirring device 100 reaches a predetermined load setting value (hereinafter sometimes referred to as "pump start"), the raw material supply pump and the discharge pump start (hereinafter referred to as "storage"). (Sometimes referred to as "initial freezing").

In addition, in the control device 60, when manufacturing frozen desserts (hereinafter sometimes referred to as "manufacturing"), the compressor control section 61 controls the frequency F of the compressor 2, and the hot gas control section 62 controls the frequency F of the compressor 2. By controlling the opening degree of the hot gas valve 9, the temperature of the frozen dessert produced by the stirring device 100 is adjusted. Further, during manufacturing, the expansion valve control section 63 controls the opening degree of the expansion valve 4 to adjust the height of the liquid level of the liquid refrigerant in the evaporator 5.

In addition, the control device 60 closes the expansion valve 4 to drive the compressor 2 and collects the refrigerant liquefied in the condenser 3 into the receiver 8 so that no liquid refrigerant remains in the evaporator 5 at the end of production. For this purpose, each device is controlled while detecting the pressure of the refrigerant in the evaporator 5 and the accumulator 6 and the height of the liquid refrigerant in the evaporator 5. Hereinafter, the operation of the frozen dessert manufacturing apparatus 1 under this control may be referred to as "refrigerant recovery operation at the end of manufacturing". This is because if liquid refrigerant is present in the evaporator 5 when production is stopped, the pressure in the evaporator 5 and accumulator 6 will increase, and the refrigerant will be released from the low-pressure side safety valve 35, which is dangerous.

In addition, in the control device 60, when the frozen dessert is not being manufactured, the pressure in the evaporator 5 and the accumulator 6 is detected by the evaporation pressure sensor 31, and when the detected pressure reaches a predetermined upper limit pressure, the pressure in the compressor is The compressor 2 is activated at a predetermined frequency, and when the detected pressure drops to a predetermined lower limit pressure, the compressor 2 is controlled to be stopped. Hereinafter, the operation of the frozen dessert manufacturing apparatus 1 under this control may be referred to as "pressure holding operation during production stop". The control device 60 repeatedly starts and stops the compressor 2 under the above-mentioned control when the evaporation pressure increases when production is stopped.

Below, the control performed by the control device 60 during manufacturing, the control of refrigerant recovery operation at the end of manufacturing, and the control of pressure holding operation at the time of stopping manufacturing will be described in detail.
(Control during manufacturing)
In the frozen dessert manufacturing apparatus 1, when the operating frequency of the compressor 2 is increased, gaseous refrigerant flows into the compressor 2 from the evaporator 5 and the accumulator 6, thereby reducing the pressure of the refrigerant in the evaporator 5. Furthermore, when the operating frequency of the compressor 2 is reduced, gaseous refrigerant is prevented from flowing into the compressor 2 from the evaporator 5 and the accumulator 6, and the pressure of the refrigerant in the evaporator 5 increases.
Furthermore, in the evaporator 5, the refrigerant has a property that as the pressure increases, the temperature also increases, and as the pressure decreases, the temperature decreases.
In the frozen dessert manufacturing apparatus 1 of this embodiment, based on this relationship, the frequency of the compressor 2 is controlled based on the pressure of the refrigerant in the evaporator 5 and the accumulator 6 detected by the evaporation pressure sensor 31, and the frequency of the compressor 2 is controlled based on the pressure of the refrigerant in the evaporator 5 and the accumulator 6, By controlling the opening degree of the cooling valve 9, the temperature of the refrigerant is controlled within a predetermined range.

The compressor control unit 61 controls the frequency F of the compressor 2 based on the pressure P of the gaseous refrigerant in the accumulator 6 detected by the evaporation pressure sensor 31. In other words, the compressor control unit 61 controls the frequency F of the compressor 2 based on the pressure of the gaseous refrigerant evaporated in the evaporator 5. More specifically, the compressor control unit 61 increases the frequency F of the compressor 2 when the pressure P detected by the evaporation pressure sensor 31 becomes larger than a predetermined set evaporation pressure Px. Increase the rotation speed of the motor 2c. On the other hand, when the pressure P detected by the evaporation pressure sensor 31 becomes lower than the set evaporation pressure Px, the compressor control unit 61 lowers the rotational speed of the motor 2c in order to lower the frequency F of the compressor 2. .
However, the compressor control unit 61 rotates the compressor 2 within a predetermined frequency range.

The hot gas control unit 62 reduces the opening degree of the hot gas valve 9 when the pressure P detected by the evaporation pressure sensor 31 is equal to or higher than the set evaporation pressure Px.
On the other hand, the hot gas control unit 62 increases the opening degree of the hot gas valve 9 when the pressure P detected by the evaporation pressure sensor 31 is smaller than the set evaporation pressure Px. Thereafter, the hot gas control unit 62 maintains the opening degree of the hot gas valve 9 when the pressure P detected by the evaporation pressure sensor 31 becomes equal to the set evaporation pressure Px.

FIG. 4 is a flowchart illustrating an example of frequency change processing performed by the compressor control unit 61.
The compressor control unit 61 repeatedly executes the frequency change process at preset fixed time intervals (for example, 1 millisecond).
The compressor control unit 61 determines whether the pressure P detected by the evaporation pressure sensor 31 is equal to the set evaporation pressure Px (S401). If the pressure P is not equal to the set evaporation pressure Px (No in S401), the compressor control unit 61 determines whether the pressure P detected by the evaporation pressure sensor 31 is greater than the set evaporation pressure Px (S402). If the pressure P is greater than the set evaporation pressure Px (Yes in S402), the compressor control unit 61 increases the frequency F of the compressor 2 (S403). After that, the compressor control unit 61 performs the process of S401.

On the other hand, if the pressure P is not greater than the set evaporation pressure Px (No in S402), the compressor control unit 61 lowers the frequency F of the compressor 2 (S404). After that, the compressor control unit 61 performs the process of S401.
If the pressure P is equal to the set evaporation pressure Px (Yes in S401), the compressor control unit 61 maintains the frequency F of the compressor 2 (S405).

FIG. 5 is a flowchart showing an example of the opening degree changing process of the hot gas valve 9 performed by the hot gas control unit 62.
The hot gas control unit 62 repeatedly executes the opening degree changing process at preset constant time intervals (for example, 1 millisecond).
The hot gas control unit 62 determines whether the pressure P detected by the evaporation pressure sensor 31 is equal to the set evaporation pressure Px (S501). If the pressure P is not equal to the set evaporation pressure Px (No in S501), the hot gas control unit 62 determines whether the pressure P detected by the evaporation pressure sensor 31 is greater than the set evaporation pressure Px (S502). If the pressure P is higher than the set evaporation pressure Px (Yes in S502), the hot gas control unit 62 reduces the opening degree of the hot gas valve 9 (S503). After that, the hot gas control unit 62 performs the process of S501.

On the other hand, if the pressure P is not higher than the set evaporation pressure Px (No in S502), the hot gas control unit 62 increases the opening degree of the hot gas valve 9 (S504). After that, the hot gas control unit 62 performs the process of S501.
When the pressure P is equal to the set evaporation pressure Px (Yes in S501), the hot gas control unit 62 maintains the opening degree of the hot gas valve 9 (S505).

In this way, in the control device 60, the compressor control section 61 adjusts the frequency of the compressor 2, and the hot gas control section 62 adjusts the opening degree of the hot gas valve 9, so that the evaporator 5 The pressure of the evaporated gaseous refrigerant is controlled to be the set evaporation pressure Px. Since the refrigerant has a characteristic in the evaporator 5 that as the pressure increases, the temperature also increases, and as the pressure decreases, the temperature decreases. Therefore, the control device 60 controls the refrigerant pressure to a predetermined value. By controlling the refrigerant, the temperature of the refrigerant is controlled to a predetermined value. Thereby, the temperature of the frozen dessert produced by the stirring device 100 is controlled to a predetermined value.

The expansion valve control unit 63 controls the opening degree of the expansion valve 4 using the detected height h, which is the height of the liquid level of the liquid refrigerant in the evaporator 5 detected by the liquid level sensor 32. When the detected height h is higher than a predetermined set height hx, the expansion valve control unit 63 reduces the opening degree of the expansion valve 4 to reduce the amount of liquid refrigerant supplied to the evaporator 5. let On the other hand, when the detected height h is lower than the set height hx, the expansion valve control unit 63 increases the opening degree of the expansion valve 4 to increase the amount of liquid refrigerant supplied to the evaporator 5.

In this way, the expansion valve control unit 63 controls the opening degree of the expansion valve 4 so that the level of the liquid refrigerant reaches the predetermined set height hx. Note that the lower limit height hn is set to the height of the lowest surface of the evaporator 5 of the liquid refrigerant. The upper limit height hm is set to the upper limit height of the liquid refrigerant to the liquid level sensor.

In the frozen dessert manufacturing apparatus 1 configured as described above, when the liquid refrigerant in the evaporator 5 evaporates and the liquid level of the liquid refrigerant decreases, the expansion valve control section 63 controls the expansion valve 4. Increase the opening. The expansion valve 4 is a so-called motor valve, and since the degree of opening of the valve gradually increases, the amount of refrigerant that passes through the expansion valve 4 and is supplied to the evaporator 5 gradually increases.
Here, if there is a large amount of liquid refrigerant in the evaporator 5, cooling of the frozen dessert will be facilitated, and if there is little liquid refrigerant in the evaporator 5, cooling of the frozen dessert will be difficult to be promoted. Let us consider a case where the expansion valve 4 is a solenoid valve that completely closes the refrigerant flow path when it is off and fully opens the refrigerant flow path when it is turned on. When the expansion valve 4 is a solenoid valve, a large amount of liquid refrigerant flows into the evaporator 5 at once when it is turned on and the flow path is fully open from an off state in which the refrigerant flow path is fully closed. On the other hand, when the solenoid valve is turned on and the refrigerant flow path is fully open, when it is turned off and the flow path is fully closed, liquid refrigerant no longer flows into the evaporator 5. As a result, the amount of liquid refrigerant flowing into the evaporator 5 fluctuates rapidly due to switching between on and off of the solenoid valve, and the temperature of the frozen dessert tends to fluctuate greatly.
On the other hand, in the frozen dessert manufacturing apparatus 1 according to the present embodiment, the opening degree of the expansion valve 4 gradually changes, so the amount of liquid refrigerant flowing into the evaporator 5 gradually changes. As a result, fluctuations in the temperature of the frozen dessert are also small.

(Refrigerant recovery operation at the end of production)
At the end of production, the refrigerant present in the evaporator 5 is collected into the receiver 8.
When the user performs a predetermined operation to end the manufacturing during manufacturing (for example, when a stop button is pressed), the control device 60 closes the expansion valve 4 and stops the raw material supply pump and the discharge pump. Further, the control device 60 causes the compressor 2 to continue operating at a predetermined frequency. Further, the control device 60 causes the stirring device 100 to continue operating at a predetermined constant frequency.
Then, the control device 60 closes the hot gas valve 9 when the detected height h detected by the liquid level sensor 32 decreases to a predetermined height.
Further, when the pressure of the refrigerant in the evaporator 5 and accumulator 6 detected by the evaporation pressure sensor 31 drops to a predetermined pressure, the control device 60 stops the compressor 2 and turns on the stirring device 100. make it stop.

At the end of production, the evaporator 5 does not evaporate the refrigerant and the heat of evaporation is not consumed, so if the refrigerant remains in the evaporator 5, the temperature of the remaining refrigerant increases. Here, if a large amount of refrigerant exists in the evaporator 5, the pressure of the refrigerant tends to increase as the temperature rises. On the other hand, in the frozen dessert manufacturing apparatus 1 of the present embodiment, a part of the refrigerant present in the evaporator 5 is recovered into the receiver 8 at the end of manufacturing, thereby making it difficult for the pressure of the refrigerant to increase.

Further, at the end of manufacturing, the control device 60 does not stop supplying chiller water to the condenser 3, but continues to supply chiller water during manufacturing. As a result, the refrigerant collected in the liquid receiver 8 is cooled by the condenser 3 and the temperature of the liquid receiver 8 is maintained at a low temperature, so that the pressure of the refrigerant in the liquid receiver 8 is unlikely to increase.
Note that after stopping the production of frozen desserts, the hot gas control unit 62 increases the opening degree of the hot gas valve 9 to be larger than 0 until the raw material mix in the cylinder inner tube 110 is melted, and the hot gas is controlled by the stirring device. 100 may be supplied.

(Pressure holding operation when production is stopped)
After the refrigerant recovery is completed, the compressor control unit 61 controls the compressor 2 based on the pressure P of the gaseous refrigerant in the accumulator 6 detected by the evaporation pressure sensor 31. More specifically, as described above, the compressor control unit 61 stops the rotation of the motor 2c after the refrigerant recovery is completed. Then, the compressor control unit 61 rotates the motor 2c when the pressure P detected by the evaporation pressure sensor 31 becomes higher than a predetermined upper limit pressure Py. Then, the compressor control unit 61 stops the rotation of the motor 2c when the pressure P detected by the evaporation pressure sensor 31 becomes equal to or lower than a predetermined lower limit pressure Pm.
The compressor control unit 61 continues to perform the above control while the production of frozen desserts is stopped.

By the way, when production is stopped, the refrigerant present in the evaporator 5 and accumulator 6 is recovered to the liquid receiver 8 as described above, but it is difficult to recover all the refrigerant, and some refrigerant remains in the evaporator 5 and accumulator 6. There are cases where Since the refrigerant used in the frozen dessert manufacturing apparatus 1 is a CO ₂ refrigerant, even if a part of the refrigerant is recovered into the liquid receiver 8, the time elapsed after the production of frozen desserts was stopped and the production of frozen desserts The pressure of the refrigerant tends to increase due to an increase in the ambient temperature of the device 1 or the like.
Furthermore, when manufacturing is stopped, so-called CIP (Cleaning In Place) cleaning may be performed in which sterile water heated to a predetermined temperature is supplied to the space S1 of the cylinder inner cylinder 110 to clean it. Since the temperature of the sterilized water used for CIP cleaning is as high as about 85° C., if refrigerant remains in the evaporator 5, the pressure of the refrigerant may rise rapidly.
If the pressure of the refrigerant becomes excessively high, there is a risk that the refrigerant will be released to the outside of the frozen dessert manufacturing apparatus 1 via the low-pressure side safety valve 35.

In contrast, in the present embodiment, when the pressure P detected by the evaporation pressure sensor 31 becomes larger than the predetermined upper limit pressure Py, the compressor 2 is operated, so that the evaporator 5 and the accumulator 6 are operated. The refrigerant present in the liquid is collected into the liquid receiver 8. As a result, the pressure of the refrigerant in the evaporator 5 and the accumulator 6 is reduced, and an increase in the pressure of the refrigerant is suppressed. As a result, the refrigerant is prevented from being discharged to the outside of the frozen dessert manufacturing apparatus 1 via the low-pressure side safety valve 35.
Moreover, when the pressure P detected by the evaporation pressure sensor 31 becomes lower than the predetermined lower limit pressure Pm, the operation of the compressor 2 is stopped, thereby suppressing power consumption during production stoppage.

As explained above, in the frozen dessert manufacturing apparatus 1, the evaporation pressure sensor 31 detects the evaporation pressure of the gaseous refrigerant evaporated in the evaporator 5, and the control device 60 detects the evaporation pressure based on the detection result by the evaporation pressure sensor 31. to control the state (pressure) of the refrigerant in the evaporator 5. As described above, in the evaporator 5, the temperature of the refrigerant increases as the pressure increases, and the temperature decreases as the pressure decreases. As a result, the control device 60 controls the state (pressure) of the refrigerant in the evaporator 5 based on the evaporation pressure of the refrigerant, so that, for example, the refrigerant evaporates based only on the rotational load of the rotation shaft 133 detected by the inverter 136. Compared to the case where the state of the refrigerant in the container 5 is controlled, it becomes possible to accurately adjust the temperature of the raw material mix or frozen dessert cooled by the refrigerant in the evaporator 5.

In addition, the control device 60 controls the amount of water evaporated in the evaporator 5 by having the compressor control unit 61 adjust the frequency of the compressor 2 and the hot gas control unit 62 adjusting the opening degree of the hot gas valve 9. The pressure of the gaseous refrigerant is controlled to be the set evaporation pressure Px. This makes it possible to control the temperature of the refrigerant in the evaporator 5 within a predetermined range, and adjust the temperature of the raw material mix or frozen dessert cooled by the refrigerant in the evaporator 5 to a predetermined range. becomes possible.

In addition, in the embodiment described above, CO ₂ refrigerant is used as the refrigerant, but the refrigerant is not limited to this. As the refrigerant, in addition to the CO ₂ refrigerant, for example, a known fluorocarbon refrigerant may be used.

Furthermore, in the embodiment described above, the frozen dessert manufacturing apparatus 1 includes both the stirring device 100 and the refrigeration cycle that cools the raw material mix etc. stirred by the stirring device 100. may be provided in a device different from the frozen dessert manufacturing device 1.

1... Frozen dessert manufacturing device, 2... Compressor, 3... Condenser, 4... Expansion valve, 5... Evaporator, 6... Accumulator, 7... Heat exchanger, 8... Liquid receiver, 9... Valve for hot gas, 11 ... Separator, 12 ... Return section, 51 ... Refrigerant circuit, 52 ... Branch path, 60 ... Control device, 61 ... Compressor control section, 62 ... Hot gas control section, 63 ... Expansion valve control section, 100 ... Stirring device, 110... Cylinder inner cylinder, 120... Cylinder outer cylinder, 130... Stirring section

Claims (4)

a compressor that compresses refrigerant;
a condenser that condenses the refrigerant compressed by the compressor;
an expansion valve that expands the refrigerant condensed in the condenser;
an evaporator that performs heat exchange between the refrigerant expanded by the expansion valve and the raw material of the frozen dessert to cool the raw material and evaporate the refrigerant;
a detection unit that detects the evaporation pressure of the gaseous refrigerant evaporated in the evaporator;
A frozen dessert manufacturing apparatus comprising: a control device that controls a state of refrigerant in the evaporator based on a detection result by the detection section. The frozen dessert manufacturing apparatus according to claim 1, wherein the control device controls the state of the refrigerant in the evaporator so that the evaporation pressure becomes a predetermined set pressure. The control device controls the state of the refrigerant in the evaporator by adjusting the operating frequency of the compressor or the amount of high-temperature gaseous refrigerant discharged from the compressor supplied to the evaporator. The frozen dessert manufacturing apparatus according to claim 1, characterized in that: The frozen dessert manufacturing apparatus according to any one of claims 1 to 3, characterized in that carbon dioxide is used as a refrigerant.