Fire-resistant oil constant temperature device for volume resistivity measurement and volume resistivity measuring instrument

Abstract

The utility model relates to a fire-resistant oil thermostat for measuring volume resistivity, comprising: an outer electrode thermostat structure and an inner electrode thermostat structure; the outer electrode thermostat structure comprises a bath jacket (30), a semiconductor refrigeration sheet (19), a heat sink (17), a fan (16), a heating rod (34) and a temperature measuring element (23); the semiconductor refrigeration sheet (19) is attached to the inner wall of the bath jacket (30), the heat sink (17) is wrapped around the outer surface of the bath jacket (30), and the fan (16) is arranged outside the heat sink (17); the heating rod and the temperature measuring element (23) are placed in the inner cavity of the bath jacket (30); the inner electrode thermostat structure comprises an oil cup, a water pump (11), a refrigeration box assembly (14), a three-way (12), a manual ball valve (13) and a water cup (10) which are sequentially connected through a quick connector (8) and a pipeline (9), and the refrigeration box assembly (14) has an M-shaped flow channel (15) inside. A volume resistivity measuring instrument comprising the fire-resistant oil thermostat is also disclosed.

Description

Technical Field

[0001] The utility model belongs to the technical field of constant temperature for measuring volume resistivity, and particularly relates to a constant temperature device for fire-resistant oil used for measuring volume resistivity and a volume resistivity measuring instrument. Background Art

[0002] Volume resistivity measurements are generally made using a test fixture electrode configuration - a voltage source Vs is applied to the top electrode, the high current through the test sample is specified as Im, and then the volume resistivity Rv is calculated using the formula: Rv = Vs / Im. The high current flowing from the test sample to the guard electrode and the surface current flowing from the top electrode to the guard electrode are both leakage currents; however, these currents will enter the low side of Vs and will not affect the magnitude of the ammeter current (Im) used to calculate Rv.

[0003] According to "DL421-2009 Electric Power Oil Volume Resistivity Determination Method", the measurement of volume resistivity requires dual temperature control of inner and outer electrodes. The oil cup specified in it is usually realized by adding a heating tube and a temperature measuring element to the inner electrode, such as: ZL200820034940.2. This method fully meets the volume resistivity measurement of insulating oil at 90℃, but when measuring the volume resistivity of fire-resistant oil at 20℃, due to the space limitation of the inner electrode, only a refrigeration device can be installed on the outer electrode. For example: ZL200520082929.X, at this time, the instrument can only complete the measurement well when the room temperature is lower than 20℃. If the room temperature is higher than 20℃, the refrigeration can only be transmitted through the outer electrode. When the inner electrode does not have a temperature measuring element, it will cause a difference between the set temperature and the actual oil temperature. When the inner electrode has a temperature measuring element, if you want to make the inner and outer electrodes reach the same temperature, it takes a long time to balance, resulting in inaccurate measurement results and poor repeatability and reproducibility. Utility Model Content

[0004] The purpose of the utility model is to provide a fire-resistant oil constant temperature device and a volume resistivity measuring instrument for measuring volume resistivity, so as to better obtain the measuring conditions of fire-resistant oil. The utility model uses an improved oil cup and a constant temperature device, which is specially used for measuring fire-resistant oil, so that the inner electrode can be quickly cooled or heated, and the temperature is quickly balanced with the outer electrode, so as to obtain a more accurate resistivity measurement result.

[0005] The utility model provides a fire-resistant oil constant temperature device for measuring volume resistivity, comprising:

[0006] External electrode constant temperature structure and internal electrode constant temperature structure;

[0007] The external electrode constant temperature structure comprises a bath jacket (30), a semiconductor cooling sheet (19), a heat sink (17), a fan (16), a heating rod (34) and a temperature measuring element (23); the semiconductor cooling sheet (19) is attached to the inner wall of the bath jacket (30), the heat sink (17) is wrapped around the outer surface of the bath jacket (30), and the fan (16) is arranged outside the heat sink (17);

[0008] The heating rod and the temperature measuring element (23) are placed in the inner cavity of the bath jacket (30);

[0009] The inner electrode constant temperature structure comprises an oil cup, a water pump (11), a refrigeration box assembly (14), a three-way joint (12), a manual ball valve (13) and a water cup (10) which are sequentially connected via a quick connector (8) and a pipeline (9); the refrigeration box assembly (14) has an M-shaped flow channel (15) inside for realizing refrigeration and heating functions.

[0010] Preferably, the temperature measuring element (23) is a temperature sensor.

[0011] Preferably, the oil cup comprises an outer electrode (1), an inner electrode (4), a shielding electrode (2), an insulating pad (3), a shielding inner core (7) and a fixing ring (6); the inner electrode (4) is separated from the shielding electrode (2) by the insulating pad (3) at the top and bottom, the shielding inner core (7) passes through the inner electrode (4) to fix the inner electrode (4), the insulating pad (3) and the shielding electrode (2) together in series, and then is connected to the outer electrode (1) through the fixing ring (6); the quick connector (8) is installed on the shielding inner core (7).

[0012] Preferably, the shielding inner core (7) has a T-shaped structure, with a U-shaped flow channel and a blind hole provided inside, three ports with internal threads and respectively fixing the quick connector (8) and the temperature measuring element (23), and the bottom of the shielding inner core (7) has an external thread for connecting the shielding pole (2).

[0013] Preferably, the refrigeration box assembly (14) includes an outer shell (18) and a fixing seat (21), a refrigeration box body (20), a semiconductor refrigeration sheet (19), a heat sink (17) and a fan (16) installed in sequence inside; the refrigeration box body (20) is fixed to the outer shell (18) through the fixing seat (21), and the interior of the refrigeration box body (20) is filled with a thermal insulation material (22), and the semiconductor refrigeration sheet (19), the heat sink (17) and the fan (16) are installed at one side of the refrigeration box body (20) to achieve the conversion between cooling and heating under room temperature detection conditions.

[0014] Preferably, the M-shaped flow channel is opened inside the refrigeration box body (20), and the port of the refrigeration box body (20) is threaded for fixing the quick connector (8) and the pipeline (9).

[0015] Preferably, the bath set (30) is circular as a whole.

[0016] Preferably, a groove for placing the oil cup is opened inside the bath jacket (30), two planes for placing the semiconductor refrigeration plate (19) are milled on both sides of the outside of the bath jacket (30), and a plurality of blind holes for installing the heating rod (34) and the temperature measuring element (23) are opened on the bottom surface of the bath jacket (30); and the interior of the bath jacket (30) is filled with thermal insulation material (22).

[0017] Preferably, the external electrode constant temperature structure further comprises a housing (33), and the semiconductor cooling sheet (19), the heat sink (17) and the fan (16) are mounted on the housing (33) after being bonded together.

[0018] The second aspect of the utility model is to provide a volume resistivity measuring instrument, comprising the fire-resistant oil constant temperature device for measuring volume resistivity according to the first aspect.

[0019] Beneficial effects of the utility model:

[0020] (1) The improved oil cup with a U-shaped flow channel on the inner electrode is specially used for measuring the volume resistivity of fire-resistant oil. The inner electrode temperature is transmitted by a fluid medium, and the medium is cooled or heated by an external refrigeration box, which solves the limitation that the refrigeration device can only be installed on the outer electrode due to the limited space of the inner electrode.

[0021] (2) The inner electrode can be cooled or heated quickly, and the temperature of the outer electrode can be quickly balanced, which is more in line with the dual measurement and dual temperature control requirements of the standard.

[0022] (3) The requirement of measuring in less than 15 minutes is met, making the volume resistivity measurement of fire-resistant fuel more accurate, and the repeatability and reproducibility are significantly improved.

[0023] The above description is only an overview of the technical solution of the utility model. In order to more clearly understand the technical means of the utility model and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the utility model in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the inner electrode constant temperature structure shown in the utility model.

[0025] Figure 2 For this utility model Figure 1 AA section view shown in .

[0026] Figure 3 This is a schematic diagram of the external electrode constant temperature structure shown in the utility model.

[0027] Figure 4 For this utility model Figure 3 BB cross-sectional view shown in . DETAILED DESCRIPTION

[0028] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0029] Embodiment 1

[0030] like Figure 1 As shown, this embodiment provides a fire-resistant oil constant temperature device for measuring volume resistivity, comprising:

[0031] External electrode constant temperature structure and internal electrode constant temperature structure;

[0032] The external electrode constant temperature structure includes a bath jacket 30, a semiconductor cooling sheet 19, a heat sink 17, a fan 16, a heating rod 34 and a temperature measuring element 23; the semiconductor cooling sheet 19 is attached to the inner wall of the bath jacket 30, the heat sink 17 is wrapped around the outer surface of the bath jacket 30, and the fan 16 is arranged outside the heat sink 17;

[0033] The heating rod and the temperature measuring element 23 are placed in the inner cavity of the bath jacket 30;

[0034] The inner electrode constant temperature structure comprises an oil cup, a water pump 11, a refrigeration box assembly 14, a three-way connection 12, a manual ball valve 13 and a water cup 10 which are sequentially connected via a quick connector 8 and a pipeline (9); the refrigeration box assembly 14 has an M-shaped flow channel 15 inside for realizing refrigeration and heating functions.

[0035] As a preferred embodiment, the temperature measuring element 23 is a temperature sensor. Those skilled in the art should know that temperature sensors with various temperature measuring principles can be used, all of which are within the protection scope of the present invention.

[0036] As a preferred embodiment, the oil cup includes an outer electrode 1, an inner electrode 4, a shielding electrode 2, an insulating pad 3, a shielding core 7 and a fixing ring 6; the inner electrode 4 is separated from the shielding electrode 2 by the insulating pad 3, and the shielding core 7 passes through the inner electrode 4 to fix the inner electrode 4, the insulating pad 3 and the shielding electrode 2 in series, and then is connected to the outer electrode 1 through the fixing ring 6; the quick connector 8 is installed on the shielding core 7.

[0037] As a preferred embodiment, the shielding inner core 7 has a T-shaped structure with a slightly thick head, a U-shaped flow channel and a blind hole inside, three ports with internal threads and respectively fixing the quick connector 8 and the temperature measuring element 23, and the bottom of the shielding inner core 7 is slightly thinner and has an external thread for connecting the shielding pole 2.

[0038] like Figure 2 As shown, as a preferred embodiment, the refrigeration box assembly 14 includes an outer shell 18 and a fixing seat 21, a refrigeration box body 20, a semiconductor refrigeration sheet 19, a heat sink 17 and a fan 16 installed in sequence inside; the refrigeration box body 20 is fixed to the outer shell 18 through the fixing seat 21, and the interior of the refrigeration box body 20 is filled with insulation material 22, and the semiconductor refrigeration sheet 19, the heat sink 17 and the fan 16 are installed on one side of the refrigeration box body 20 at one time to realize the conversion between cooling and heating under room temperature detection conditions.

[0039] In this embodiment, the room temperature detection conditions are: cooling when the room temperature is higher than 20°C, and heating when the room temperature is lower than 20°C.

[0040] As a preferred embodiment, the M-shaped flow channel is opened inside the refrigeration box body 20 , and the port of the refrigeration box body 20 is threaded for fixing the quick connector 8 and the pipeline 9 .

[0041] like Figure 3 As shown, as a preferred embodiment, the bath set 30 is circular as a whole.

[0042] As a preferred embodiment, a groove for placing the oil cup is opened inside the bath jacket 30, two planes for placing the semiconductor refrigeration plate 19 are milled on the outside of the bath jacket 30, and a plurality of blind holes for installing the heating rod 34 and the temperature measuring element 23 are opened on the bottom surface of the bath jacket 30.

[0043] In this embodiment, the number of blind holes is 3.

[0044] like Figure 4 As shown, the interior of the bath jacket 30 is filled with a heat-insulating material 22 .

[0045] As a preferred embodiment, the external electrode constant temperature structure further includes a housing 33 , and the semiconductor cooling fins 19 , the heat sink 17 and the fan 16 are mounted on the housing 33 after being bonded together.

[0046] Working principle:

[0047] When in use, the manual ball valve 13 is in a closed state, the water pump 11 is turned on, and the medium flows from the water cup 10 through the tee 12 to the refrigeration box assembly 14, passes through the M-shaped flow channel 15 inside the refrigeration box, enters the U-shaped flow channel 5 of the oil cup shielding inner core 7, and finally returns to the water cup 10 to complete the cycle. When the refrigeration box assembly 14 is cooling or heating, the medium controls the temperature of the electrode 4 in the oil cup through this cycle.

[0048] In addition to the quick connector 8, the oil cup shielding inner core 7 is also equipped with a temperature measuring element 23 to keep the temperature constant at 20°C. When in use, the room temperature is judged according to the temperature measuring element 23. When the room temperature is lower than 20°C, the heating rod 34 heats it. When the room temperature is higher than 20°C, the semiconductor cooling sheet 19 and the fan 16 cool it, and the temperature is transmitted to the outer electrode 1 of the oil cup through the bath jacket 30. Combined with the constant temperature structure of the inner electrode, the inner and outer electrodes of the fire-resistant oil cup can be quickly kept constant at 20°C.

[0049] Embodiment 2

[0050] This embodiment provides a volume resistivity measuring instrument, including the fire-resistant oil constant temperature device for measuring volume resistivity described in the first embodiment.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A constant temperature device for fire-resistant oil for measuring volume resistivity, characterized in that: include: External electrode constant temperature structure and internal electrode constant temperature structure; The external electrode constant temperature structure comprises a bath jacket (30), a semiconductor cooling sheet (19), a heat sink (17), a fan (16), a heating rod (34) and a temperature measuring element (23); the semiconductor cooling sheet (19) is attached to the inner wall of the bath jacket (30), the heat sink (17) is wrapped around the outer surface of the bath jacket (30), and the fan (16) is arranged outside the heat sink (17); The heating rod and the temperature measuring element (23) are placed in the inner cavity of the bath jacket (30); The inner electrode constant temperature structure comprises an oil cup, a water pump (11), a refrigeration box assembly (14), a three-way joint (12), a manual ball valve (13) and a water cup (10) which are sequentially connected via a quick connector (8) and a pipeline (9); the refrigeration box assembly (14) has an M-shaped flow channel (15) inside for realizing refrigeration and heating functions.

2. A constant temperature device for fire-resistant oil for measuring volume resistivity according to claim 1, characterized in that: The temperature measuring element (23) is a temperature sensor.

3. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 2, characterized in that: The oil cup comprises an outer electrode (1), an inner electrode (4), a shielding electrode (2), an insulating pad (3), a shielding inner core (7) and a fixing ring (6); the inner electrode (4) is separated from the shielding electrode (2) by the insulating pad (3) at the top and bottom; the shielding inner core (7) passes through the inner electrode (4) to fix the inner electrode (4), the insulating pad (3) and the shielding electrode (2) together in series, and then is connected to the outer electrode (1) through the fixing ring (6); the quick connector (8) is installed on the shielding inner core (7).

4. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 3, characterized in that: The shielding inner core (7) has a T-shaped structure, with a U-shaped flow channel and a blind hole provided inside, three ports with internal threads and respectively fixing the quick connector (8) and the temperature measuring element (23), and the bottom of the shielding inner core (7) with external threads for connecting the shielding pole (2).

5. A constant temperature device for fire-resistant oil for measuring volume resistivity according to claim 4, characterized in that: The refrigeration box assembly (14) comprises a refrigeration box assembly shell (18) and a fixing seat (21), a refrigeration box body (20), a semiconductor refrigeration sheet (19), a heat sink (17) and a fan (16) installed in sequence inside; the refrigeration box body (20) is fixed to the refrigeration box assembly shell (18) through the fixing seat (21), and the interior of the refrigeration box body (20) is filled with a heat insulation material (22), and the semiconductor refrigeration sheet (19), the heat sink (17) and the fan (16) are installed at one side of the refrigeration box body (20) to achieve the conversion between cooling and heating under room temperature detection conditions.

6. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 5, characterized in that: The M-shaped flow channel is provided inside the refrigeration box body (20), and a port of the refrigeration box body (20) is provided with threads for fixing the quick connector (8) and the pipeline (9).

7. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 6, characterized in that: The bathing set (30) is circular in shape as a whole.

8. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 7, characterized in that: The bath jacket (30) has a groove inside for placing the oil cup, the bath jacket (30) has two planes milled on the outside for placing the semiconductor refrigeration sheet (19), and the bottom surface of the bath jacket (30) has a plurality of blind holes for installing the heating rod (34) and the temperature measuring element (23); the bath jacket (30) is filled with thermal insulation material (22).

9. A temperature control device for fire-resistant oil for measuring volume resistivity according to claim 8, characterized in that: The external electrode constant temperature structure also includes an external electrode constant temperature structure shell (33), and the semiconductor cooling sheet (19), the heat sink (17) and the fan (16) are mounted on the external electrode constant temperature structure shell (33) after being bonded together.

10. A volume resistivity measuring instrument, characterized in that: It comprises a fire-resistant oil constant temperature device for measuring volume resistivity as described in any one of claims 1-9.

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