KR910004306B1 - Adiabatic efficiency testing device of adiabatic material for pipe laying - Google Patents

Abstract

The system is used for measuring the heat conduction coefficient of pipe insulation internal layors, considering rarious conditions e.g. exterior moisture, temperature, internal convection and so on. The measurement system comprises a heating unit (H) and a control unit (9). In the heat unit, an asbetos ribbion heater (1) is installed within a steel pipe (2), and a copper pipe (7) having a narrower diameter than the steel pipe is inserted into the steel pipe. One end of the heat unit is welded in order to over come the two pipes' length variation according to the difference of heat expansion ratios. In the control unit, thermocouples (9) are set up on the surfaces of the steel pipe and the insulator, and an electric power meter is installed for measuring supply caloxic value, and a digital pulse counter (10) is connected to the meter in order to display the caloric value.

Description

Insulation performance measuring device of pipe insulation

1 is a device schematic of the present invention.

2 is a diagram of a device of the present invention.

3 is a schematic diagram of a pulse counter device which is part of the inventive device.

The present invention relates to a device capable of measuring the thermal conductivity of the pipe insulation in the form of a pipe mainly used in industry. Insulation performance of insulation material can show considerable difference not only in external condition such as moisture, temperature, air and pressure, but also depending on the shape of pores or internal condition of insulation such as radiation in insulation layer. Performance differs from one another.

However, conventionally, since there is no device that can measure the insulation performance of the pipe insulation material, when measuring the thermal conductivity of the pipe-type insulation material used in industrial piping, replace the plate heat insulating material having the same material and density with a material, and measure this value. Although measuring the thermal insulation performance of the pipe insulation in this way has the same error as described above, the pipe-type insulation is to be measured using the insulation performance device of the independent pipe insulation of the present invention.

Hereinafter, the gist of the present invention will be described with reference to the accompanying drawings. First, the schematic diagram of the heat insulation performance measuring apparatus of the heat insulating material for piping is shown in FIG.

The apparatus of the present invention is configured as shown in FIG. 2 and has a heating unit (H) and a control unit (C). Heating part (H) is installed in the steel pipe (2) containing the asbestos ribbon heater (1) to install the heat insulating material (3) facing each other as the rock surface supplement plate (4) to any set temperature (50 ℃-200 ℃) Is a part that heats up and heats up to), and the adjusting unit (C) comprises a PID controller (P) for adjusting the surface temperature of the steel pipe (2) and a computer power meter (C) for measuring the amount of heat supplied. to be.

의 동관(7)을 삽입하고 동관(7)위에 용량 1㎾, 길이 1.5m 또는 2.5m의 석면리본히터(1) 2개를 각각 동관 양끝에서 서로 반대방향으로 감아서 강관(2)을 내부로부터 균일하게 가열토록 하고 양끝은 강판재 캡(8)으로 끼워서 지지토록 하였다.In addition, the control unit (C) is installed a digital thermometer (6) to measure the temperature at the central point of the steel pipe (2) to check whether the entire system is normally maintained. The steel pipe (2) of the heating part (H) is made of SS-41 steel (MILD STEEL), which is mainly used as an industrial pipe, and is 1m long so that the thermal conductivity can be measured while replacing it according to the inner diameter of the insulating material 3 to be measured. Use "4" steel pipe. The inside of the steel pipe (2) is smaller than the inner diameter of the steel pipe (2) and the thermal conductivity is much larger

Insert the copper pipe (7) of the pipe and wind the steel pipe (2) from the inside by winding two asbestos ribbon heaters (1) with a capacity of 1㎾, 1.5m or 2.5m on the copper pipe (7), respectively, at opposite ends of the copper pipe. It was heated evenly and both ends were supported by sandwiching the steel plate cap (8).

At one end of the heating part, the side steel plate cap 8 and the steel pipe 2 are welded at one end of the heating part so as to alleviate the variation in length due to the difference in thermal expansion rate between the steel pipe 2 and the copper pipe 7 during heating. Do not weld. In order to prevent heat loss from the side of the steel pipe (2), that is, the side steel plate cap (4) is insulated with a rock wool insulation plate (4) of 100m / m thickness. The temperature of the steel plate surface is controlled by PID controller (P), but the temperature is controlled by attaching K-TYPE thermocouple (9) to the center surface of steel pipe. In order to measure the heat dissipation, a home integrated power meter (5) is installed, but since the minimum unit of the power meter scale is too large as 10 wh, the digital pulse counter 10 (DIGITAL PULSE COUNTER) was created so that the minimum measurement unit can be displayed as 1 wh. Install and read calorie changes from here. The counter 10 is configured to increase by one unit for each rotation of the rotating plate 5a of the integrated power meter 5, and the schematic of the device is the same as that of the third diagram.

In the figure, 11 is a hole (HOLE), 12, 12 'is a photosensitive sensor, 13 is a circuit (CIRCUIT), 14 is a display (DISPLAY). The measurement is made after installing the pipe insulation (3) in the steel pipe (2) and heating, and after reaching the steady state in which the surface temperature of the steel pipe (2) and the heat insulating material (3) is kept constant, the pulse counter in the device control unit (C) The switch 15 is turned on to measure the amount of heat supplied to the heating unit every hour for 3-5 hours using the digital pulse counter 10 device. For temperature measurement, four K-TYPE thermocouples (9) are installed on the top, bottom, left and right of the center of the insulation surface at the same position as the steel pipe surface and connected to the data logger (17) (DATA LOGGER) and measured every 20 minutes. The measured values are arithmetic averaged to obtain the surface temperatures of the steel pipe (2) and the heat insulating material (2). The heat dissipation value of the pipe insulation is calculated by substituting the average heat dissipation, average steel pipe, and surface temperature of the insulation into Equation (1).

Q: Dissipation heat value (Kcal / m ² h)

K: thermal conductivity (Kcal / mh ℃)

L: length of insulation material (m)

di: outer diameter of steel pipe

do: outer diameter of insulation

Tsi: Insulation Surface Temperature

Tso: Insulation outer surface temperature

In the present invention, the accuracy of the device was examined through the following analysis. First, natural logarithm (NATURAL LOGARI-) is used for transplantation by using (Equation 1), which calculates thermal conductivity.

Take the THM) and calculate the derivative,

Becomes

(Equation 2) calculates the maximum relative error that can occur when measuring the thermal conductivity. Therefore, the result obtained by substituting the maximum change width of each measured variable to obtain this error is shown in (Table 1). At this time, considering the nonuniformity of the insulation thickness and the point that the insulation is flexible, the error due to the radius change of the insulation thickness is assumed to be 3mm.

As a result, as shown in (Table 1), the influence of the radius change of the insulation on the measurement error was 4.5%, and the effect of temperature and heat flow drifting on the measurement error was about 5%. Considering that the accuracy of the RAPID-K (DYNATECH, USA) device, which is widely used as a flat plate insulation and a thermal conductivity measuring device, is 5%, the pipe insulation insulating performance device of the present invention is satisfactory when the accuracy of the device is about 5%. As a performance, it can be widely supplied to the insulation industry as a professional insulation performance measuring device for pipe insulation.

TABLE 1

Maximum value of change of each measured variable

Claims (1)

Wind the asbestos ribbon heater (1) on the copper pipe (7) and cover the outside with a steel pipe (2), connect it to the steel plate cap (8) to stand as a support, and rotate the rotation plate (5a) of the power meter (5) at the bottom Insulation performance measuring device of the heat insulating material for the pipe that is connected to the digital pulse counter (10) to detect and integrate by 1WH.

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