JPH02213680A - Refrigerating transport vehicle - Google Patents

Abstract

PURPOSE:To stabilize the temperature in a refrigerator by detecting the temperature of brine circulating in the refrigerator by a brine temperature sensor, and so controlling ON, OFF a compressor of a refrigerant circuit that the brine temperature becomes constant. CONSTITUTION:In a refrigerating transport vehicle, refrigerant pressurized by a compressor 5 is fed to an evaporator 2 via a condenser 3 to cool a brine coil 1 in a refrigerator 11 via a brine circuit provided together at the evaporator 2 to reduce the temperature in a refrigerator to a low temperature. The temperature of the brine itself is detected by a brine temperature sensor 21, compared with a bring set temperature to control ON, OFF the compressor 5. The refrigerant heated to high temperature under high pressure to be evaporated by the compressor 5 is fed to a hot gas solenoid valve 24 and a condense switching solenoid valve 27. lf the coil 1 is frosted to lower its cooling efficiency, the valve 24 is opened, the valve 27 is closed to guide the refrigerant heated to the high temperature under high pressure to be evaporated to the coil 1 to be defrosted.

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a refrigeration mechanism for a refrigerated transport vehicle that enables the transport of frozen foods, seafood, dairy products, etc. that need to be transported at low temperatures. be.

(b) Prior Art Although refrigerated transport vehicles have been known for a long time,
In this case, the vaporized refrigerant is compressed by a compressor, evaporated at high temperature and high pressure, and discharged. Heat is radiated while the high temperature and high pressure heated vapor passes through a condenser to liquefy the low temperature and high pressure heated vapor, and the liquefied refrigerant is It was expanded using an engraved valve just before the evaporator in the freezer, turned into low-temperature, low-pressure vapor, and the heat removed during this process directly cooled the freezer.

(c) Problems to be solved by the invention As mentioned above, when refrigerant is directly supplied to the inside of a refrigerated transport vehicle by an evaporator through which the refrigerant passes, a sensor is applied to the cooling air blown from a fan installed in the evaporator. Since the temperature inside the refrigerator was detected and the rotation of the compressor was controlled based on this information, delicate temperature control was not possible, and the temperature inside the refrigerator could not be maintained constant within a narrow range. There wasn't.

In order to solve this problem, the present invention does not directly cool the inside of the warehouse with a refrigerant, but instead configures a brine circulation path as a low-temperature transfer material, and cools the brine with the cooling temperature of the evaporator. The brine coil fan provided on the brine coil is rotated to generate cooling air and send it into the refrigerator by guiding the air to the brine coil placed inside the refrigerator.

In this way, in a cooling system using brine, the sensor for automatic temperature control inside the refrigerator is used as a brine temperature sensor that directly detects the brine temperature and automatically sets the brine temperature. In comparison, it is controlled by turning the compressor ON and OFF to further stabilize the temperature inside the refrigerator.

In addition, in the refrigeration circuit using the brine circuit and the brine coil, the high-temperature, high-pressure heated and vaporized refrigerant discharged from the compressor is used as a defrost heat source to remove frost adhering to the brine coil 1 located inside the refrigerator. It was used as a heat source.

(d) Means for Solving the Problems The objects of the present invention are as described above. Next, the configuration for achieving the objects will be explained.

The refrigerant heated and vaporized at high temperature and high pressure by the compressor 5 is sent to the evaporator 2, and the brine coil 1 in the freezer 11 is cooled by the brine circuit installed in parallel with the evaporator 2. The temperature of the brine circulating in the refrigerant circuit 11 is detected by the brine temperature sensor 21, the brine set temperature is automatically determined, and the compressor 5 of the refrigerant circuit is ON-OFF controlled so that the brine temperature is constant. It is.

In addition, the frost adhesion state in the freezer 11 is detected by a slight differential pressure switch 23 installed on the brine coil, and the refrigerant in the high temperature, high pressure heated steam state discharged from the compressor 5 is released by opening the hot gas solenoid valve 24. The frost is guided to the brine coil 1 to defrost the frost adhering to the brine coil 1.

(E) Embodiment The object and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

Fig. 1 is a side view of the refrigerated transport vehicle of the present invention, Fig. 2 is a perspective plan view thereof, Fig. 3 is a refrigeration circuit diagram of the refrigerated transport vehicle of the present invention, and Fig. 4 shows a control sensor and a control operating section. Block diagram, Figure 5 is a diagram showing the change in the outlet air temperature in the case of the outlet air temperature control method, Figure 6 is a diagram showing the change in the outlet air temperature in the case of the brine temperature control method, and Figure 7 is the refrigeration A diagram showing the process of change in temperature of each part at the start, and FIGS. 8 to 16 are diagrams showing a temperature control flowchart of the refrigeration mechanism.

The arrangement of each part of the refrigeration mechanism in the refrigeration transport vehicle will be explained with reference to FIGS. 1 and 2.

A freezer 11 is arranged on a frame at the rear of the driver's cab 12.

In the space between the driver's cab 12 and the freezer 11, an internal cooling device A, which is a main part of the present invention, is arranged.

Inside the driver's cab 12, a controller H incorporating electronic equipment for automatic temperature control is placed behind the driver's seat, and a display and operation panel D for the refrigeration mechanism is located in front of the driver's seat.
is located.

Further, a humidifier outdoor device C is arranged on the right side of the frame on the bottom surface of the freezer II.

The humidifier external device C includes a water tank, a humidifier compressor, and the like.

Further, on the lower right side of the freezer 11, a condenser unit B is arranged as an outdoor unit of the internal refrigeration system.

Further, an accumulator E is arranged at the lower part of the internal cooling device A, and a relay box F is arranged at the front part thereof.

Next, referring to FIG. 3, the refrigeration mechanism of the refrigerated transport vehicle of the present invention will be explained.

The refrigeration mechanism is divided into a device inside the freezer 11 and a device outside the freezer 11.

An evaporator 2 and a brine cooling mechanism are arranged in the refrigerator, and a humidifier 7 of the humidifier is also arranged.

First, let me explain about the cooling system using refrigerant.

The refrigerant is supplied to a compressor 5 driven by an engine 4.
It is heated and vaporized at high temperature and high pressure.

In the circuit for driving the compressor 5 by the engine 4, a clutch mechanism 35 is provided at the V-pulley, and the temperature inside the freezer 11 can be adjusted by connecting and disconnecting the clutch mechanism 35.

The main part of the claim ( ) of the present invention is that the brine temperature sensor 2
1 detects the temperature of the brine itself in the brine circuit,
This challenge value is compared with the brine set temperature Tb to control the ON/OFF of the compressor 5.

The refrigerant heated and vaporized at high temperature and high pressure by the compressor 5 passes through an oil separator 14 to separate a gas portion and an oil (refrigeration machine oil) portion, and only the gas portion is sent to a hot gas solenoid valve 24 and a condenser switching solenoid valve 27. reach.

The main part of claim (2) of the present invention is this brine coil 1
When cooling efficiency decreases due to frost buildup, the hot gas provided in the passage path of the high-temperature, high-pressure heated steam refrigerant is removed by opening the magnetic valve 24 and closing the condenser switching solenoid valve 27.
The refrigerant heated and vaporized at high temperature and high pressure is guided to the brine coil 1 and defrosted.

Normally, the capacitor switching solenoid valve 27 opens and the capacitor 3
leading to.

The condenser 3 is cooled by a condenser fan 26, and the condenser fan 26 is controlled to be connected or disconnected by a pressure switch 25.

While the refrigerant passes through the condenser 3, it radiates heat into the atmosphere and changes from high-temperature, high-pressure heated vapor to low-temperature, high-pressure liquid.

If the conversion from vapor to liquid is insufficient, the pressure switch 25 detects the high pressure state of the refrigerant vapor and rotates the condenser fan 26 to promote heat dissipation of the refrigerant from the condenser 3.

Next, the refrigerant in a low-temperature, high-pressure liquid state is separated into gas and liquid by the receiver 17, passes through a dryer filter 18, a sight glass 19, and a pump-down solenoid valve 20, and then passes through an expansion valve 3.
This leads to 2.

The expansion valve 32 vaporizes the low-temperature, high-pressure liquid refrigerant and changes it to low-temperature, low-pressure steam, which absorbs heat from the brine in the evaporator 2 and lowers the temperature of the brine.

In addition, a high/low pressure switch 33 and a low pressure expansion valve 34 are connected in parallel to the pump down solenoid valve 20, expansion valve 32, and evaporator 2.
are arranged to form a safety circuit in the event of an abnormality.

Further, a parallel circuit constituted by a capillary tube 43 is provided from the expansion valve 32, and the degree of superheat of the expansion valve 32 is adjusted.

In the evaporator 2, the refrigerant that absorbs heat from the brine and evaporates to become superheated steam passes through the accumulator E and the check pulp 40, returns to the compressor 5, and cools the evaporator 2 by repeating this circuit.

In conventional refrigerated transportation vehicles, the evaporator fan is installed in the evaporator 2, and the interior of the refrigerator is cooled by circulating the air inside the refrigerator and bringing it into contact with the evaporator 2. However, in the present invention, Rather than using the evaporator 2 to directly cool the air inside the refrigerator, a brine cooling path is interposed between the evaporators 2 and the evaporator 2 to indirectly cool the interior of the refrigerator.

Next, let me explain about the brine cooling circuit.

Brine is a liquid made of chemical substances that easily absorb and radiate heat, and is discharged and circulated by the brine pump 30.

A pressure switch 31 is provided in the discharge path from the brine pump 30 to detect the brine discharge pressure and detect the rotation of the brine pump by 3°0. While the brine discharged from the brine pump 30 passes through the evaporator 2, the evaporator 2 absorbs the temperature of the brine, and the temperature of the brine is lowered.

The cooled brine is temporarily stored in the brine tank 6 and passes through the brine coil 1 while suppressing brine temperature fluctuations, and is then transferred to the brine fan 22 in the heat exchanger configured by the brine coil 1. This is to cool the air inside the warehouse that is circulated by.

In the present invention, a brine temperature sensor 21 is provided in the brine pipe extending from the brine tank 6 to the brine coil 1, and serves as the main sensor for temperature control inside the refrigerator.

In addition, a slight differential pressure switch 2 is placed before and after the brine coil l.
3 is provided to detect the passing state of cooling air from the brine fan 22 passing through the brine coil 1, detect whether frost is attached to the brine coil 1, and control ON/OFF of the defrost circuit. There is.

Further, a brine coil temperature sensor 16 is provided on the surface of the brine coil 1, and the surface temperature of the brine coil 1 is also detected.

The micro differential pressure switch 23 determines that defrosting is necessary when certain conditions are reached, and opens the hot gas solenoid valve 24 to switch the capacitor. 27 to perform the defrost operation.

Further, inside the freezer 11, an internal temperature sensor 28 and an internal humidity sensor 29 are arranged.

The 8-fiber line circulates between the evaporator 2 and the brine coil 1 by the fi-line bomb 30 to maintain a constant low temperature inside the refrigerator.

As described above, the signals from the sensors of each part provided in the refrigeration circuit are concentrated in the controller H, and the controller H makes a comparative judgment, and the relay box F
The relay box F operates the actuators of each part to automatically control the temperature.

Sensors that input signals to the controller H include a brine coil temperature sensor 16, a brine temperature sensor 21, a slight differential pressure switch 23, and an internal temperature sensor 2.
8. There is an internal humidity sensor 29, and the signals detected by these sensors are input to the controller "H".

Actuators output from relay box F include hot gas solenoid valve 24, capacitor switching solenoid valve 27, pump-down solenoid valve 20, clutch mechanism 35, brine pump 30, brine fan 22, humidifier 7, etc. It is something.

Next, this will be explained with reference to FIGS. 5 and 6.

In the present invention, as shown in FIG. 6, the temperature of the brine itself is controlled by a brine temperature sensor 21,
The temperature a of the air blown out from the brine fan 22 to cool the inside of the refrigerator is controlled.

Conversely, as shown in Fig. 5, when the temperature of the air blown from the brine fan 22 is detected and controlled, the brine temperature changes with a large amplitude and period as shown in Fig. 5. However, when the brine temperature is detected and controlled by the brine temperature sensor 21 as in the present invention, the changes in both the blown air temperature a and the brine temperature have small amplitudes and small cycles. , the temperature inside the refrigerator remains constant.

Next, referring to FIG. 7, the control mechanism of the refrigeration circuit of the present invention will be explained.

The temperature inside the warehouse is set by the operator, but the temperature required for frozen transportation is usually determined, and is determined for each type of frozen food, seafood, and dairy products.

Assuming that the set internal temperature T has been set from the beginning, the internal temperature of the freezer 11 is detected by the internal temperature sensor 28 at (■) in Fig. 7, and is about 15 degrees Celsius higher than the detected internal temperature. The temporary brine temperature Tb' is automatically set to the lowered temperature. At the same time, the compressor 5 is driven to lower the brine temperature toward the temporarily set brine temperature Tb'.

7, when the temperature inside the refrigerator detected by the refrigerator temperature sensor 28 reaches the set temperature T in the refrigerator, the brine temperature at this point is detected, and this temperature is detected by the brine temperature sensor 21. The brine temperature is set at Tb.

In (■) in FIG. 7, when the brine temperature detected by the brine temperature sensor 21 becomes lower than the brine set temperature Tb by ΔT1, the compressor 5 is stopped.

At (■) in FIG. 7, after the compressor 5 is stopped by the above operation (■), record the temperature THmin when the temperature inside the refrigerator reaches its lowest (lowest).

7, if the brine temperature increases by ΔT2 after the compressor 5 is turned off, the compressor 5 is turned on again.

In ■ in Figure 7, the value THm when the temperature inside the refrigerator reaches its highest after the above ■
ax is recorded and a new brine set temperature Tb is updated using the following formula.

T Hmax - T Hmin New Tb = Old Tb - (-T) , and set a new one.

From then on, this control is repeated.

Next, the flowcharts shown in FIGS. 8 to 16 will be explained.

Figure 8 shows the overall configuration of the refrigeration flowchart based on power ON, and between (contact signal input) and (analog value calculation) in Figure 8, the (timer interrupt) chart in Figure 9 is displayed at any time. It is inserted every second.

A rough flowchart of the operation shown in FIG. 8 is shown in FIG. 10.

Furthermore, the section (refrigeration operation) in FIG. 10 is divided into six sections in FIG.

That is, (refrigeration operation) (initial operation) (hysteresis control) (brine set temperature change) (A/C parallel control '4'nI
> (Actuator output determination)
Specific flowcharts are disclosed for each unit in FIGS. 12 to 15.

A flowchart of (initial operation) is disclosed in FIG.

A flowchart of (hysteresis control) is disclosed in FIG.

A flowchart of (brine setting temperature change) is disclosed in FIG.

(Initial operation) (Hysteresis control) (Brine setting temperature change) is a flowchart of the control portion explained in detail in FIG. 7 above.

That is, this is a flowchart showing the setting control process from the temporary brine setting temperature Tb'' to the new brine setting temperature Tb.

(A/C parallel control) is described in a flowchart in parallel with (refrigeration operation) in FIG.

This (A/C parallel control) is to perform cooling air conditioning in the driver's cab 12 at the same time using an air conditioner when there is sufficient output from the four engines.

Further, (actuator output determination) is disclosed in FIG.
The brine pump 30, condenser fan 26, brine fan 22, compressor 5, etc. are turned on and off.

Also, (refrigeration operation) and (defrost operation) are performed alternately.
is disclosed in FIG.

This (defrost operation) is performed only when the defrost conditions are satisfied, taking into consideration the detection signals from the slight differential pressure switch 23 of the brine coil 1, the internal temperature sensor 28, etc.

(F) Effects of the Invention Since the present invention is constructed as described above, it has the following effects.

First, since it is configured as claimed in claim (1), the temperature inside the freezer 11 is lower than when the inside of the freezer 11 is cooled by providing an evaporator fan to the evaporator 2 cooled by a refrigerant as in the past. can be kept constant, and as shown in Fig. 6, a more stable internal temperature can be obtained than in the case where the brine temperature is controlled by the temperature a of the air blown from the brine coil 1, as shown in Fig. 5. It is.

As claimed in claim (2), when frost adheres to the brine coil l of the brine circuit provided in the refrigerator, the problem is where to obtain the heat source for the defrost operation. In the invention, if frost builds up inside the refrigerator,
The hot gas from the high-temperature, high-pressure heated and vaporized refrigerant discharged from the compressor 5 is guided from the magnetic valve 24 to the brine coil 1 as a heat source, making it possible to defrost reliably with a simple mechanism. It is.

[Brief explanation of the drawing]

Fig. 1 is a side view of the refrigerated transport vehicle of the present invention, Fig. 2 is the same (perspective plan view), Fig. 3 is a refrigeration circuit diagram of the refrigerated transport vehicle of the present invention, and Fig. 4 shows the control sensor and control actuator. 5 is a diagram showing the change in the outlet air temperature in the case of the outlet air temperature control method, FIG. 6 is a diagram showing the change in the outlet air temperature in the case of the brine temperature control method, and FIG. 7 is a diagram showing the change in the outlet air temperature in the case of the brine temperature control method. Drawings showing the change process of temperature of each part at the start of freezing, and Figs. 8 to 16 are drawings showing temperature control flowcharts of this refrigeration mechanism.A...Interior cooling device B...Condenser unit C. ... Humidifier external device D ... Display operation panel E ... Accumulator F ... Relay box E ... Brine coil 2 ... Evaporator 3 ... Capacitor 4 ... Engine 5 ... Compressor 6... Brine tank Applicant Yanmar Diesel Co., Ltd. Agent Patent attorney Hisashi Yano Part 1

Claims (2)

[Claims] (1) The refrigerant pressurized by the compressor 5 is sent to the evaporator 2, and the brine coil 1 inside the freezer 11 is
In a refrigerated transportation vehicle that cools the inside of the freezer and keeps the interior at a low temperature, the temperature of the brine circulating in the freezer 11 is detected by a brine temperature sensor 21, and the brine set temperature is automatically determined so that the brine temperature is kept constant. A refrigerated transportation vehicle characterized in that the compressor 5 of the refrigerant circuit is controlled to be ON-OFF. (2) The frost adhesion state inside the freezer 11 according to claim (1) is detected by the brine temperature sensor 21 and the internal temperature sensor 28, and the refrigerant in the high temperature, high pressure heated vapor state discharged from the compressor 5 is heated. A refrigerated transport vehicle characterized in that the frost adhering to the brine coil 1 is defrosted by guiding the gas to the brine coil 1 by opening a gas solenoid valve 24.