JPH0726878B2 - Automatic measuring device for heat transmission coefficient of cool body - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to an automatic heat transmission coefficient measuring device for a cold-insulated vehicle used for a cold-insulation performance test of a cold-insulated vehicle of a refrigerated / frozen vehicle that transports cargo at a constant temperature.

[Prior art]

The cold insulation performance test of the cold insulation body is specified by JIS (Japanese Industrial Standard) (JIS-D1701-1976). The test conditions are determined as follows. (1) The test location shall be a room where there is no influence of direct sunlight, various heat sources, etc., and the variation in ambient temperature during the measurement time is within the range of 3 ° C, or an equivalent location. (2) Preheating or precooling of the vehicle body is performed until the temperature inside the vehicle body becomes stable. (3) The temperature difference between the inside of the car body and the outside of the car body should be 20 ° C or more. (4) Measurements for calorific value calculation shall be performed every 30 minutes after preheating or precooling of the vehicle body is completed. (5) The measured temperature is represented by the average value of each measurement point outside and inside the vehicle body during one measurement. (6) The temperature used for calorific value calculation has a change of 2 ° C.
The average value of 5 consecutive measurements within the range (7) The supply heat source during the measurement time is constant. (8) Stir with a fan or the like so that the temperature inside the vehicle body becomes uniform. Then, it is prescribed that the test be conducted by the following method under such conditions. As shown in FIG. 4 and FIG. 5, there are seven positions inside the cold-insulated vehicle body 1 (positions A to G of filled circles) and five outside positions.
The temperature is measured at a total of 12 points (the positions of circles H to L that are not filled) and the heat transmission coefficient K is obtained by an internal heating method or an internal cold insulation method. When using the internal heating method,
As shown in FIG. 6, an electric heater 2 is installed in the cold-insulated vehicle body 1, and the radiant heat is shielded by a radiant heat shield plate 3 while keeping the cold-insulated vehicle body 1
The inside is heated, and the heat is agitated by the fan 4 installed in the cold insulation vehicle body 1. In this state, the voltage of the electric heater 2 is adjusted by the voltage adjuster 5 so that the temperature difference between the inside and outside of the cold insulated body 1 is 20
Adjust the voltage E ₁ and current I ₁ of the electric heater 2 when the temperature is 20 ° C or higher, and measure the voltage E ₂ and current of the fan 4 at the same time by measuring with the voltmeter 6 and the ammeter 7, respectively. Measure I ₂ with a voltmeter 6 and an ammeter 7, respectively. Then, the heat transmission coefficient K is obtained by the following formula. Q = 0.86 (I ₁ · E ₁ + I ₂ · E ₂ · η) = 0.86 · W …… (3) Where, K: heat transmission coefficient Kcal / m ² h ℃ Q: heat transfer Kcal / h S: transfer Heat area m ² S ₁ : Outer surface area of cool body m ² S ₂ : Inner surface area of cool body m ² I ₁ : Electric heater current A I ₂ : Fan electric current A E ₁ : Electric heater voltage V E ₂ : Electric fan voltage V 0.86: Heat quantity of 1 watt of electric power Kcal / h η: Power factor of electric fan motor θ ₁ : Outside air temperature ℃ θ ₂ : Cooling body internal temperature ℃ W: Electric power W Thermal conductivity obtained by the above formula (1) K is calculated by the following formula based on the thermal conductivity of the cold insulating material when the central temperature of the heat insulating wall is 10 ° C. Where, K ₁₀ : heat transmission coefficient K at the central temperature of the insulation wall of 10 ℃
cal / m ² h ℃ m: Temperature coefficient for the thermal conductivity of the cold insulating material [Delta] [lambda] / lambda theta: central temperature 10 ° C. K of the heat insulating wall: measured thermal transmittance _{^{Kcal / m 2 h ℃ θ 1}} : outside air during measurement Temperature ℃ θ ₂ : Cooling body internal temperature during measurement ℃

[Problems to be Solved by the Invention]

However, conventionally, all the measurement work and the calculation according to the above-mentioned rules are artificially performed, and there are the following problems. (A) It takes about 5 to 6 hours to rise from room temperature to + 20 ° C, and it takes about 2.5 hours to collect data, even for a 2 ton vehicle class, insulated body with 100 mm thick insulation, so a total of 8 to 8
It takes 9 hours of work, during which time the voltage regulator 8 must be adjusted by almost one worker. (B) Wiring work for each device, manual calculation, etc. require a high degree of specialized knowledge and skills, and no one can easily establish a system.
Therefore, the measurement frequency tends to be low, and sufficient heat transmission coefficient cannot be measured. (C) Labor hours are long due to professional engineers, and labor costs are very high. In view of such problems, the present invention measures the heat transmission coefficient in full compliance with the JIS regulations as described above, without using a special air-conditioning room for accommodating the cold insulation body, and in a normal room computer The purpose is to be able to automatically measure using.

[Means for Solving the Problems]

The automatic heat transmission coefficient measuring device of the present invention comprises the following components. A keyboard for entering outside dimensions, inside dimensions, etc. of a cold-insulated car body. A plurality of temperature sensors respectively installed at predetermined positions inside the cold-insulated vehicle body. A plurality of temperature sensors installed at predetermined positions outside the cold-insulated vehicle body. A temperature input section that inputs the temperature detected by these internal and external temperature sensors as a digital value. An electric heater installed in the cold-insulated vehicle body. A heater voltage transducer that detects the voltage of this electric heater as a digital value. A heater current transducer that detects the electric current of the electric heater as a digital value. A fan installed inside the cold-insulated vehicle body. A fan voltage transducer that detects the voltage of this fan as a digital value. A fan current transducer that detects the fan current as a digital value. From the outer dimension and inner dimension entered from the keyboard, the outer surface area S ₁ , the inner surface area S ₂ , and the heat transfer area S of the cold-insulated vehicle body are calculated.
A first calculation unit that calculates A second calculation unit that calculates an average temperature value θ ₁ outside the cold-insulated vehicle body, an average temperature value θ ₂ inside, and an average temperature difference θ ₂ −θ ₁ inside and outside according to the temperature input from the temperature input unit. From the preset temperature of several stages,
Select the set temperature corresponding to the above average temperature difference θ ₂ −θ ₁ ,
A control amount is determined from the selected set temperature, the voltage of the electric heater is adjusted according to the control amount, and the adjustment is performed by adjusting the temperature at each point in the cold-insulated vehicle body and the average temperature difference θ ₂
-Heater voltage controller that continues until θ ₁ meets the specified conditions. Judge whether the average temperature difference θ ₂ −θ ₁ is more than the specified value,
Above a predetermined level, the heater voltage E ₁ from the heater voltage transducer and the heater current I ₁ from the heater current transducer are used to calculate the heater power I ₁ , E ₁ , the fan voltage E ₂ from the fan voltage transducer and the fan current I from the fan current transducer. ₂ and fan power from I ₂ · E ₂
A third calculation unit for obtaining Similarly, when the average temperature difference θ ₂ −θ ₁ is equal to or more than the specified value, the heat transmission coefficient is calculated from the average temperature difference, the electric power, and the heat transfer area according to the above-described equations (1), (2), and (3). 4 calculation unit. A data output unit that outputs the calculation results of the first to fourth calculation units to a display device, a printer, or the like.

[Action]

By inputting the outer dimensions and inner dimensions of the cold insulation body from the keyboard and installing the temperature sensor at the specified location of the cold insulation body, the outer surface area, inner surface area, heat transfer area of the cold insulation body,
Also, the average temperature value of the outside, the average temperature value of the inside, and the average temperature difference between the inside and the outside are automatically calculated, and the voltage of the electric heater is automatically adjusted so that the average temperature difference becomes equal to or more than the specified value. When this exceeds the prescribed value, the electric power of the electric heater and the electric power of the fan are automatically calculated, and further, the heat transmission coefficient is automatically calculated from these electric power, the average value, and the heat transfer area.
Each calculation result can be displayed or printed out on a display device.

【Example】

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a system configuration diagram of an automatic heat transmission coefficient measuring device according to the present invention, in which 10 is a console board as a whole, which is mainly a personal computer 11 and its display device (CRT) 12, keyboard 13, function keyboard 14 , I / O box 15, heater voltage controller 1
6, heater voltage transducer 17, heater current transducer 18, fan voltage transducer 19, fan current transducer 20. For measurement, keep the cool body 2 in accordance with the above-mentioned JIS regulations.
Temperature sensors 22 are installed at 7 internal points and 5 external points of 1 and are connected to the I / O box 15 by wiring, and the electric heater 23 installed in the cold storage body 21 is connected to the heater voltage controller 16 and the heater voltage transducer 17. , The heater current transducer 18 is wired, and the fans 24 and 25 installed in the cool body 21 are wired to the fan voltage transducer 19 and the fan current transducer 20. FIG. 2 is a block diagram of the system configuration shown in FIG. 1 in terms of its function, and FIG. 3 is a flowchart thereof. In FIG. 3, in step 51, the outside dimensions, the inside dimensions, the pressure difference between the inside and outside, the leaked air amount, the cold insulation material, the outer skin material, the inner skin material, the thickness of the cold insulation material, etc. When input, the process proceeds to step 52, where the external surface area S ₁ , the internal surface area S ₂ , the heat transfer area S, and the internal volume of the cold-insulated vehicle body 21 are the first and second values shown in FIG. Arithmetic section
26, and the airtightness test value (also JIS-D1701-1976
Based on) is also calculated. Assuming that the outer and inner lengths of the cold-insulated car body 21 are L ₁ , L ₂ , the widths are W ₁ , W ₂ , and the heights are H ₁ , H ₂ , the outer surface area S ₁ and the inner surface area S ₂ are respectively It can be calculated as follows. S ₁ = {(L ₁ × W ₁ ) + (W ₁ × H ₁ ) + (L ₁ × H ₁ )} × 2 S ₂ = {(L ₂ × W ₂ ) + (W ₂ × H ₂ ) + (L ₂ × H ₂ )} × 2 At step 53, it is confirmed from the calculation result whether the key input data is out of specification. If it is out of specification, the input data correction program is executed in step 54. If it is within the specified range, the routine proceeds to step 55, where the equipment is prepared, that is, the temperature sensor 22, the electric heater 23, and the fans 24, 25 are initialized. Whether or not the preparation is completed is confirmed in step 56, and if NO, the preparation correction program is executed in step 57. After preparation of the equipment, in step 58, preheating temperature rise is started, that is, the electric heater 23 and the fans 24 and 25 are turned on to uniformly heat the inside of the cold insulation vehicle body 21. Next, at step 59, the internal temperature and the external temperature (outside air temperature) of the cold-insulated vehicle body 21 detected by the temperature sensor 22 are input to the temperature input section 27 (FIG. 2) of the I / O box 15.
Is taken in as a digital amount, and the second arithmetic unit 28 calculates the temperature average value of the outside 5 points of the cold insulation body 21, the temperature average value of the inside 7 points, and the average temperature difference between the inside and outside thereof, and in step 60 from this average temperature difference. Select the set temperature. That is, a preset temperature corresponding to the average temperature difference between the inside and outside calculated in step 59 is selected from preset preset temperatures, and the heater voltage controller 16 is controlled from the selected preset temperature. The heater voltage controller 16 determines the control amount to be used, and the electric heater
Adjust the voltage of 23. In this example, the electric power of the electric heater 23 is controlled by PID (proportional / integral / derivative) control in step 62. Next, in step 63, the measurement start condition is set, and in step 64, the matching is performed. For example, the average temperature difference between inside and outside is
The conditions are 29 ° C or higher, temperature fluctuations within the vehicle body is within 2 ° C within 30 minutes, and temperature variations at 7 points within the vehicle body are within 5 ° C. Set the electric heater 23 as described above until the conditions are met. Control. If the conditions are met, the routine proceeds to step 65, where the temperatures detected inside and outside the vehicle body by the 12 temperature sensors 22 are continuously taken in, and further, the heater voltage controller 16, the heater voltage transducer 17, the heater current transducer 1
8. The voltage and current of the electric heater 23 and the voltage and current of the fans 24 and 25 by the fan voltage transducer 19 and the fan current transducer 20 are taken in, that is, measured, and the temperature average value inside and outside the vehicle body and the average temperature difference between the inside and outside are as described above. The above-mentioned measurement is performed every 30 minutes for 5 times while confirming in step 66 whether or not the condition of (3) is continuously met. If the condition is not met, an alarm is generated in step 67 and the condition conforming operation as described above is performed again. If the measurement is completed five times in a state that meets the conditions, the measurement is completed and the electric heater 23 is turned off in step 68, and then the result calculation is performed in step 69, that is, the second calculation in FIG.
The calculation unit 28 calculates the average outside air temperature θ ₁ for 5 times and the average vehicle body internal temperature θ ₂ for 5 times, and the third calculation unit 29 calculates the average heater voltage E ₁ and current I ₁ for 5 times.
The average fan voltage E ₂ and the current I ₂ for five times are calculated, and the average power W for five times is calculated, and based on these calculation results, the fourth calculation unit 30 calculates the heat transmission coefficient K and its converted value K _{10 at} 10 ° C. Is calculated. Finally, in step 70, the data output unit 31
Output to the display device 12 for display and, if necessary, output to the printer 32 for printing. The power factor η of the fan motor required to calculate the heat transmission coefficient is set as software unique to the fan motor in this example because the same fan is always used. You can also enter. In addition, in FIG.
Although they are classified into two calculation units, it is needless to say that this is a convenience and one processor can perform all calculations as a hardware configuration. Further, in the above embodiment, the heater voltage controller 16,
The heater voltage transducer 17, the heater current transducer 18, the fan voltage transducer 19, and the fan current transducer 20 used the analog / digital conversion (A / D conversion) function, but the analog output type You may use it by connecting an A / D converter. The heater voltage controller 16 is not limited to the one having the A / D conversion function itself, but a ready-made A / D conversion function.
A type with a D converter attached may also be used.

【The invention's effect】

According to the present invention, the external dimensions of the cold insulation body from the keyboard,
If the temperature sensor is installed at a specified location on the cold insulation body while inputting the internal dimensions, etc., the outer surface area, the inner surface area, the heat transfer area of the cold insulation body, the average temperature value of the outside, the average temperature value of the inside, the outside temperature of the inside and outside Mean temperature difference is automatically calculated, and the electric heater voltage is automatically adjusted so that the mean temperature difference exceeds the specified value. When this exceeds the specified value, the electric heater power and fan power are automatically adjusted. The heat transmission coefficient is automatically calculated from the electric power, the average value, and the heat transfer area, and the respective calculation results can be displayed or printed out on the display device. Therefore, in order to measure the heat transmission coefficient of a cold-insulated car body without using a special air-conditioning room that can accommodate the cold-insulated car body, an electric heater is used so that the temperature difference between the inside and outside of the cold-insulated car body becomes more than the specified value in a normal room (factory, etc.). Can be automatically measured while automatically adjusting, and can perform high-precision measurement that completely complies with JIS's strict standards. Adjustment and measurement that requires troublesome and highly specialized knowledge and skill due to conventional manual work. -No calculation work is required, accuracy is improved, and costs are reduced.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing this in terms of function, FIG. 3 is a flow chart thereof, and FIGS. 4 to 6 are JIS cold body testing. It is explanatory drawing explaining a method, FIG. 4 is a side view of a cold-insulated vehicle body, FIG. 5 is a rear view of the same, and FIG. 6 is an electric system diagram. 11 …… Personal computer, 12 …… Display device (CRT), 13 …… Keyboard, 14 …… Function keyboard, 15 …… I / O box, 16 …… Heater voltage controller, 17 …… Heater voltage transducer, 18…
… Heater current transducer, 19 …… Fan voltage transducer, 20 …… Fan current transducer, 21
...... Cold car body, 22 …… Temperature sensor, 23 …… Electric heater,
24,25 ...... Fan, 26 ...... First calculation section, 27 ...... Temperature input section, 28 ...... Second calculation section, 29 ...... Third calculation section, 30 ...
... 4th arithmetic unit, 31 ... data output unit, 32 ... printer.

Claims (1)

[Claims] 1. A keyboard for inputting outer dimensions, inner dimensions, etc. of a cold-insulated car body, a plurality of temperature sensors respectively installed at predetermined positions inside the cold-insulated car body, and a predetermined outside of the cold-insulated car body. A plurality of temperature sensors installed at each position, a temperature input unit for inputting the temperature detected by these internal and external temperature sensors as a digital value, an electric heater installed in the cold insulation vehicle body, and a voltage of this electric heater A heater voltage transducer that detects a digital value, a heater current transducer that detects a current of the same electric heater as a digital value, a fan installed in the cold-insulated vehicle body, and a voltage of this fan that detects a digital value. A fan voltage transducer, a fan current transducer that detects the fan current as a digital value, and the above keyboard The external surface area S ₁ , the internal surface area S ₂ , and the heat transfer area S of the cold-insulated vehicle from the external dimensions and the internal dimensions input from the mode, and the temperature input from the temperature input section. According to the second calculation unit for calculating the average temperature value of the outside of the cold-insulated body θ ₁ , the average temperature value of the inside θ ₂ and the average temperature difference of the inside and outside θ ₂ −θ ₁ , and the preset temperature of several stages. From among them, the set temperature corresponding to the average temperature difference θ ₂ −θ ₁ is selected, the control amount is determined from the selected set temperature, the voltage of the electric heater is adjusted according to this control amount, and the adjustment is performed. , The temperature of each point in the cold insulated body and the average temperature difference θ ₂ − θ ₁
There a heater voltage controller to continue until a predetermined condition is satisfied, the mean temperature difference theta ₂ - [theta] ₁ is determined whether more than specified, when more than a predetermined heater voltage E ₁ and the heater current transducer by the heater voltage transducer Due to current I ₁
Heater power I ₁ · E ₁ from the above by the fan voltage transducer from the fan voltage E ₂ and the fan current transducer by a fan current I ₂ Metropolitan and third calculation unit for obtaining the fan power I ₂ · E _2, also mean temperature difference When θ ₂ −θ ₁ is greater than or equal to the specified value, a fourth calculation unit that calculates the heat transmission coefficient from the average temperature difference, the power, and the heat transfer area according to the following equations (1), (2), and (3). And a data output unit for outputting the calculation results of the first to fourth calculation units to a display device, a printer, or the like. Q = 0.86 (I ₁ · E ₁ + I ₂ · E ₂ · η) = 0.86 · W …… (3) Where, K: heat transmission coefficient Kcal / m ² h ℃ Q: heat transfer Kcal / h S: transfer Heat area m ² S ₁ : Outer surface area of cool body m ² S ₂ : Inner surface area of cool body m ² I ₁ : Electric heater current A I ₂ : Fan current A E ₁ : Electric heater voltage V E ₂ : Fan voltage V 0.86: Heat quantity of 1 watt of electric power Kcal / h η: Power factor of fan motor θ ₁ : Outside temperature of cold body ℃ θ ₂ : Inside temperature of cold body ℃ W: Electric power W