Hydraulic oil external circulation self-heating device

Abstract

The utility model relates to a hydraulic oil external circulation self-heating device, an oil tank comprises a tank body, a liquid outlet and a liquid return port, the liquid outlet and the liquid return port are connected with the tank body, the external circulation self-heating device is used for heating hydraulic oil in the oil tank, and the external circulation self-heating device comprises a first circulating pump, a second circulating pump and a third circulating pump, the outer circulating pipeline is connected with the first circulating pump and the liquid return opening; and the electric heating assembly is connected with the outer wall of the outer circulating pipeline. Compared with the prior art, the defect that hydraulic oil is emulsified due to local high temperature of the hydraulic oil in the prior art can be overcome, the temperature of the hydraulic oil is more uniform, and local high temperature is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of oil well control, in particular to a self-heating device for external circulation of hydraulic oil. Background Art

[0002] As a key component of well control equipment, the blowout preventer control system works as follows: high-pressure hydraulic oil is stored by a high-pressure pump unit and then delivered to the opening / closing cylinders of the blowout preventer to control the opening and closing of the blowout preventer. In the cold regions of Northeast China and Xinjiang in China, the low temperature of the hydraulic oil increases its viscosity, prolonging the pressurization process time of the blowout preventer control system and the time for opening and closing the blowout preventer, resulting in the failure to meet the usage requirements for the opening and closing time of the blowout preventer, interrupting on-site operations and causing huge economic losses. The existing hydraulic oil heating system is designed to directly heat the hydraulic oil in contact with the heating device, and the hydraulic oil is relatively static without stirring or circulation, resulting in large temperature measurement errors, causing local high temperature of the hydraulic oil and leading to the emulsification of the hydraulic oil.

[0003] Patent Publication No. CN202661898U discloses an intelligent control system for the temperature of hydraulic oil in a hydraulic system, which includes an electric heating element, a control box, a fuel tank temperature sensor, an electric heating element temperature sensor, and an input display module. The electric heating element is arranged on the outer wall of the fuel tank, the fuel tank temperature sensor is inserted into the fuel tank, the electric heating element temperature sensor is inserted between the electric heating element and the outer wall of the fuel tank, the input display module is placed at the operation table, and the control box is placed at the upper end of the fuel tank and is respectively connected to the electric heating element, the fuel tank temperature sensor, the electric heating element temperature sensor, and the input display module. However, this control system cannot solve the problem of local high temperature of the hydraulic oil. Content of the Utility Model

[0004] The purpose of the utility model is to overcome the defect of local high temperature of the hydraulic oil leading to emulsification of the hydraulic oil in the above-mentioned existing technology, and to provide a self-heating device for external circulation of hydraulic oil to ensure more uniform temperature and avoid local high temperature.

[0005] The purpose of the utility model can be realized by the following technical solutions:

[0006] A self-heating device for external circulation of hydraulic oil is used to heat the hydraulic oil in a fuel tank. The fuel tank includes a box body and an outlet and a return port connected thereto. The external circulation self-heating device includes:

[0007] A first circulation pump connected to the outlet and used to extract the hydraulic oil in the fuel tank;

[0008] An external circulation pipeline connected to the first circulation pump and the return port;

[0009] And an electric heating component connected to the outer wall of the external circulation pipeline.

[0010] Furthermore, the liquid outlet and the liquid return port can be at any position on the box body.

[0011] Furthermore, the external circulation pipeline includes:

[0012] A first connecting pipe connected to the first circulation pump;

[0013] A second connecting pipe connected to the liquid return port;

[0014] A serpentine pipe with both ends respectively connected to the first connecting pipe and the second connecting pipe.

[0015] Furthermore, the electric heating component is arranged on the outer wall of the serpentine pipe or between adjacent straight pipes of the serpentine pipe.

[0016] Furthermore, a first connector is arranged at the port of the first connecting pipe, and a second connector is arranged at the port of the second connecting pipe. The settings of the first connector and the second connector can make the first connecting pipe and the second connecting pipe more conveniently connected to other pipes, connectors, fuel tanks, circulation pumps, etc. Their shapes and types can be selected according to the actual situation.

[0017] Furthermore, the first connecting pipe and the second connecting pipe can be hard pipes or flexible pipes, so as to place the external circulation pipeline and the electric heating component in a suitable position according to the actual space without occupying space.

[0018] Furthermore, the electric heating component includes a single-head electric heating rod, an electric heating tube, an electric heating plate, and an electric heating sheet, which are used to perform the heating function, and in the form of electric heating, it occupies a small floor space and does not require too much space.

[0019] Furthermore, this external circulation self-heating device further includes a second circulation pump located between the liquid return port and the external circulation pipeline. The first circulation pump at the liquid outlet pumps the hydraulic oil in the fuel tank into the external circulation pipeline and then returns to the liquid return port. The second circulation pump is used to improve the external circulation power of the hydraulic oil to ensure that the hydraulic oil in the external circulation pipeline can completely return to the fuel tank without being blocked and accumulated due to the shape of the external circulation pipeline.

[0020] Furthermore, a temperature sensor is arranged between the liquid outlet and the first circulation pump.

[0021] Furthermore, this external circulation self-heating device further includes a control box connected to the power supply, which is connected to the temperature sensor, the electric heating component, and the first circulation pump.

[0022] Furthermore, the control box includes:

[0023] A first circuit with both ends respectively connected to the first circulation pump and the live wire;

[0024] A second circuit with two ends respectively connected to the electric heating component and the first circuit, and the electric heating component is also connected to the neutral line;

[0025] A third circuit with two ends respectively connected to the temperature sensor and the first circuit and simultaneously controlling the connection or disconnection of the first circuit and the second circuit;

[0026] And a grounding wire.

[0027] Furthermore, a first wire and a second wire are connected to the electric heating component, and are respectively connected to the neutral line and the second circuit.

[0028] Furthermore, the third circuit includes a thermostat, a thermostat thermal open contact, an intermediate relay coil, a contactor coil, and a switch assembly connected in sequence to the temperature sensor wire. The switch assembly includes a control selection switch and a first switch circuit, a second switch circuit, and a zero position button wire-connected thereto. The first switch circuit, the second switch circuit, and the zero position button are connected in parallel.

[0029] Furthermore, a normally open contact of an intermediate relay is provided on the first switch circuit, which is an automatic switch circuit; a stop button and a start button are connected in series on the second switch circuit, and the start button is connected in parallel with a normally open contact, which is a manual switch circuit, and other switch forms can also be adopted.

[0030] Furthermore, a fuse including a fuse wire is also connected to the third circuit, and the fuse is connected to the switch assembly and the second single circuit.

[0031] Furthermore, a normally open contact of a contactor is provided on the first circuit, which is located between the connection point of the first circuit and the second circuit and the connection point of the first circuit and the third circuit.

[0032] Furthermore, a circuit breaker and a thermal overload relay are also provided on the first circuit. The circuit breaker is used to cut off and connect the load circuit, and cut off the fault circuit to prevent the accident from expanding and ensure safe operation; the thermal overload relay is used for overload protection.

[0033] Furthermore, a first signal lamp is connected in parallel to the switch assembly. When the control selection switch rotates from the zero position button to be connected to the first switch circuit; or when the control selection switch rotates from the zero position button to be connected to the second switch circuit and the start button is pressed, after the contactor coil is powered on, the first signal lamp lights up, indicating that the device is powered on.

[0034] Furthermore, a second signal lamp is connected in parallel with the contactor coil. When the temperature sensor detects that the temperature at the liquid outlet is lower than the set temperature in the thermostat, the thermal open contact of the thermostat closes, the coil of the intermediate relay is energized, the coil of the contactor is energized, and the second signal lamp lights up, indicating that the device is operating; when the temperature sensor detects that the temperature at the liquid outlet is more than 10 °C higher than the set temperature in the thermostat, the thermal open contact of the thermostat disconnects, the coil of the intermediate relay is de-energized, the coil of the contactor is de-energized, and the second signal lamp goes out, indicating that the device is not operating.

[0035] Furthermore, a normally open contact of a thermal overload relay and a third signal lamp are connected in parallel with the first signal lamp, and the normally open contact of the thermal overload relay and the third signal lamp are connected in series. When the thermal overload relay is activated, the normally open contact of the thermal overload relay closes, the circuit is energized, and the third signal lamp lights up, indicating that the device is in a thermal overload condition, reminding the staff to handle it.

[0036] Compared with the prior art, the present utility model has the following advantages:

[0037] (1) The present utility model realizes the external circulation self-heating of the well control equipment. The external circulation of the hydraulic oil ensures that its temperature is more uniform and avoids local high temperature; the heating device adopts an electric heating component, and by heating the external circulation pipeline, the direct contact between the heating device and the hydraulic oil is avoided, increasing the reliability and redundancy of the heating system.

[0038] (2) The present utility model adopts an external electric heating component, which is arranged on the outer wall of the serpentine pipeline. The serpentine pipeline has a compact structure and can be connected to other pipelines, connectors, oil tanks, circulation pumps, etc. through the first connector of the first connecting pipe and the second connector of the second connecting pipe. In the form of electric heating, it occupies a small space and does not require too much space.

[0039] (3) The present utility model is connected to the temperature sensor, the electric heating component, and the first circulation pump through a control box. When the temperature sensor detects that the temperature at the liquid outlet is greater than the set temperature in the thermostat, the control box controls the electric heating component and the first circulation pump to work for external circulation self-heating. When the temperature sensor detects that the temperature at the liquid outlet is more than 10 °C higher than the set temperature in the thermostat, the control box controls the electric heating component and the first circulation pump to stop working. It can effectively control the temperature of the hydraulic oil in the oil tank and keep it at a stable temperature all the time. Description of the Drawings

[0040] Figure 1 It is a schematic structural diagram of the external circulation self-heating device shown in Embodiment 1;

[0041] Figure 2Schematic structural diagram of the external circulation self-heating device shown in Embodiment 2;

[0042] Figure 3 Circuit diagram of the external circulation self-heating device shown in Embodiment 2;

[0043] Figure 4 Schematic structural diagram of the external circulation self-heating device shown in Embodiment 3.

[0044] Explanation of the markings in the figure:

[0045] 1 - fuel tank, 11 - box body, 12 - liquid outlet, 13 - liquid return port;

[0046] 2 - first circulation pump;

[0047] 3 - external circulation pipeline, 31 - first connecting pipe, 311 - first connector, 32 - second connecting pipe, 321 - second connector, 33 - serpentine pipeline;

[0048] 4 - electric heating component, 41 - first electric wire, 42 - second electric wire;

[0049] 5 - temperature sensor;

[0050] 6 - control box, 61 - first circuit, 611 - normally open contact of the contactor, 612 - circuit breaker, 613 - thermal overload relay, 62 - second circuit, 63 - third circuit, 631 - temperature controller, 632 - thermal open contact of the temperature controller, 633 - coil of the intermediate relay, 634 - coil of the contactor, 635 - switch assembly, 6351 - control selection switch, 6352 - first switch circuit, 6353 - second switch circuit, 6354 - zero position button, 6355 - normally open contact of the intermediate relay, 6356 - stop button, 6357 - start button, 6358 - normally open contact, 636 - fuse, 637 - first signal lamp, 638 - second signal lamp, 639 - third signal lamp, 6391 - normally open contact of the thermal overload relay, 64 - live wire, 65 - neutral wire, 66 - ground wire;

[0051] 7 - second circulation pump. Detailed implementation mode

[0052] The present utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiments are implemented on the premise of the technical solution of the present utility model, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present utility model is not limited to the following embodiments. In the following embodiments or implementation modes, if there are no specially described functional components or structures, it means that they are all conventional components or conventional structures adopted in the art to achieve the corresponding functions.

[0053] It should be noted that in the description of the present utility model, the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0054] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, terms such as "installation", "provided with", "connection", etc. shall be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific situations.

[0055] Embodiment 1

[0056] A hydraulic oil external circulation self-heating device, as Figure 1 shown, is used to heat the hydraulic oil in the fuel tank 1. The fuel tank 1 includes a tank body 11 and a liquid outlet 12 and a liquid return port 13 connected thereto. The external circulation self-heating device includes:

[0057] A first circulation pump 2 connected to the liquid outlet 12 and used to extract the hydraulic oil in the fuel tank 1;

[0058] An external circulation pipeline 3 connected to the first circulation pump 2 and the liquid return port 13;

[0059] And an electric heating component 4 connected to the outer wall of the external circulation pipeline 3.

[0060] In this embodiment, the liquid outlet 12 and the liquid return port 13 are on the side wall of the tank body 11, and they can be selected at any position of the tank body 11.

[0061] In this embodiment, the external circulation pipeline 3 includes:

[0062] A first connecting pipe 31 connected to the first circulation pump 2;

[0063] A second connecting pipe 32 connected to the liquid return port 13;

[0064] A serpentine pipeline 33 with both ends respectively connected to the first connecting pipe 31 and the second connecting pipe 32.

[0065] In this embodiment, the electric heating component 4 is arranged between adjacent straight pipes of the serpentine pipe 33. A first connector 311 is provided at the port of the first connecting pipe 31, and a second connector 321 is provided at the port of the second connecting pipe 32. The settings of the first connector 311 and the second connector 321 enable the first connecting pipe 31 and the second connecting pipe 32 to be more conveniently connected to other pipes, connectors, the fuel tank 1, the circulation pump, etc., and their shapes and types can be selected according to actual situations. The first connecting pipe 31 and the second connecting pipe 32 can be flexible pipes, so that the external circulation pipe 3 and the electric heating component 4 can be placed in appropriate positions according to the actual space without occupying space.

[0066] In this embodiment, the electric heating component 4 is a single-head electric heating rod, which is used to perform the heating function, and it adopts the form of electric heating, occupying a small floor space and not requiring too much space.

[0067] Embodiment 2

[0068] A hydraulic oil external circulation self-heating device, as Figure 2 and 3 shown, is used to heat the hydraulic oil in the fuel tank 1. The fuel tank 1 includes a box body 11 and a liquid outlet 12 and a liquid return port 13 connected thereto. The external circulation self-heating device includes:

[0069] A first circulation pump 2 connected to the liquid outlet 12 and used to extract the hydraulic oil in the fuel tank 1;

[0070] An external circulation pipe 3 connected to the first circulation pump 2 and the liquid return port 13;

[0071] And an electric heating component 4 connected to the outer wall of the external circulation pipe 3.

[0072] In this embodiment, the liquid outlet 12 and the liquid return port 13 are on the side wall of the box body 11, and they can be selected at any position of the box body 11.

[0073] In this embodiment, the external circulation pipe 3 includes:

[0074] A first connecting pipe 31 connected to the first circulation pump 2;

[0075] A second connecting pipe 32 connected to the liquid return port 13;

[0076] A serpentine pipe 33 with both ends respectively connected to the first connecting pipe 31 and the second connecting pipe 32.

[0077] In this embodiment, the electric heating component 4 is arranged between adjacent straight pipes of the serpentine pipe 33. A first connector 311 is provided at the port of the first connecting pipe 31, and a second connector 321 is provided at the port of the second connecting pipe 32. The settings of the first connector 311 and the second connector 321 enable the first connecting pipe 31 and the second connecting pipe 32 to be more conveniently connected to other pipes, connectors, the fuel tank 1, the circulation pump, etc., and their shapes and types can be selected according to actual situations. The first connecting pipe 31 and the second connecting pipe 32 can be flexible pipes, so that the external circulation pipe 3 and the electric heating component 4 can be placed in appropriate positions according to the actual space without occupying space.

[0078] In this embodiment, the electric heating component 4 is a single-head electric heating rod for performing the heating function, and it adopts the form of electric heating, occupying a small floor space and not requiring too much space.

[0079] In this embodiment, a temperature sensor 5 is arranged between the liquid outlet 12 and the first circulation pump 2. The external circulation self-heating device further includes a control box 6 connected to a power supply, which is connected to the temperature sensor 5, the electric heating component 4, and the first circulation pump 2.

[0080] In this embodiment, the control box 6 includes:

[0081] A first circuit 61 with two ends respectively connected to the first circulation pump 2 and the live wire 64;

[0082] A second circuit 62 with two ends respectively connected to the electric heating component 4 and the first circuit 61, and the electric heating component 4 is also connected to the neutral wire 65;

[0083] A third circuit 63 with two ends respectively connected to the temperature sensor 5 and the first circuit 61 and simultaneously controlling the connection or disconnection of the first circuit 61 and the second circuit 62;

[0084] And a grounding wire 66.

[0085] In this embodiment, a first wire 41 and a second wire 42 which are respectively connected to the neutral wire 65 and the second circuit 62 are connected to the electric heating component 4.

[0086] In this embodiment, the third circuit 63 includes a thermostat 631, a thermostat thermal open contact 632, an intermediate relay coil 633, a contactor coil 634, and a switch assembly 635 that are sequentially connected to the temperature sensor 5 by wire. The switch assembly 635 includes a control selection switch 6351 and a first switch circuit 6352, a second switch circuit 6353, and a zero position button 6354 that are connected to it by wire. The first switch circuit 6352, the second switch circuit 6353, and the zero position button 6354 are connected in parallel. An intermediate relay normally open contact 6355 is provided on the first switch circuit 6352. A stop button 6356 and a start button 6357 are connected in series on the second switch circuit 6353. The start button 6357 is connected in parallel with a normally open contact 6358.

[0087] In this embodiment, a fuse 636 is also connected to the third circuit 63. In this embodiment, it is a fuse wire. The fuse 636 is connected to the switch assembly 635 and the second single circuit 62.

[0088] In this embodiment, a contactor normally open contact 611 is provided on the first circuit 61, which is located between the connection point of the first circuit 61 and the second circuit 62 and the connection point of the first circuit 61 and the third circuit 63.

[0089] In this embodiment, a circuit breaker 612 and a thermal overload relay 613 are also provided on the first circuit 61. The circuit breaker 612 is used to cut off and connect the load circuit, as well as cut off the faulty circuit to prevent the accident from expanding and ensure safe operation. The thermal overload relay 613 is used for overload protection.

[0090] In this embodiment, a second signal lamp 638 is connected in parallel to the switch assembly 635. When the control selection switch 6351 rotates from the zero position button 6354 to be connected to the first switch circuit 6352; or when the control selection switch 6351 rotates from the zero position button 6354 to be connected to the second switch circuit 6353 and the start button 6357 is pressed, after the contactor coil 634 is powered on, the first signal lamp 637 lights up, indicating that the device is powered on.

[0091] In this embodiment, a second signal lamp 638 is connected in parallel with the contactor coil 634. When the temperature sensor 5 detects that the temperature at the liquid outlet 12 is lower than the set temperature in the thermostat 631, the thermal open contact 632 of the thermostat closes, the intermediate relay coil 633 is energized, the contactor coil 634 is energized, and the second signal lamp 638 lights up, indicating that the device is operating. When the temperature sensor 5 detects that the temperature at the liquid outlet 12 is higher than the set temperature in the thermostat 631 by more than 10 °C, the thermal open contact 632 of the thermostat opens, the intermediate relay coil 633 is de-energized, the contactor coil 634 is de-energized, and the second signal lamp 638 goes out, indicating that the device is not operating.

[0092] In this embodiment, a first signal lamp 637 is connected in parallel with a normally open contact 6391 of a thermal overload relay and a third signal lamp 639. The normally open contact 6391 of the thermal overload relay and the third signal lamp 639 are connected in series. When the thermal overload relay is activated, the normally open contact 6391 of the thermal overload relay closes, the circuit is energized, and the third signal lamp 639 lights up, indicating that the device is in a thermal overload condition, reminding the staff to handle it.

[0093] The working process and working principle of the external circulation self-heating device in this embodiment are as follows:

[0094] Close the circuit breaker 612 on the first circuit 61. When the control selection switch 6351 on the third circuit 63 selects the automatic mode, rotate it from the zero position button 6354 to connect to the first switch circuit 6352. The normally open contact 6355 of the intermediate relay closes, the first switch circuit 6352 is energized, and the first signal lamp 637 lights up, indicating that the device is powered on.

[0095] When the temperature sensor 5 detects that the temperature at the liquid outlet 12 is lower than the set temperature in the thermostat 631, the normally open thermal contact 632 of the thermostat closes, the coil 633 of the intermediate relay is energized, the coil 634 of the contactor is energized, the normally open contact 611 of the contactor on the first circuit 61 closes, the third circuit 63 is connected to the second circuit 62 and the first circuit 61, and the first circulation pump 2 and the electric heating component 4 operate. This enables the hydraulic oil in the fuel tank 1 to flow into the external circulation pipeline 3 from the liquid outlet 12 through the first circulation pump 2 and be heated by the electric heating component 4. At this time, the second signal lamp 638 lights up, indicating that the device is operating. When the temperature sensor 5 detects that the temperature at the liquid outlet 12 is more than 10°C higher than the set temperature in the thermostat 631, the normally open thermal contact 632 of the thermostat opens, the coil 633 of the intermediate relay is de-energized, the coil 634 of the contactor is de-energized, the normally open contact 611 of the contactor on the first circuit 61 opens, the third circuit 63 is not connected to the second circuit 62 and the first circuit 61, and the first circulation pump 2 and the electric heating component 4 stop operating. At this time, the second signal lamp 638 lights up, indicating that the device is not operating. In this way, the external circulation self-heating of the hydraulic oil in the fuel tank 1 is realized.

[0096] When the control selection switch 6351 on the third circuit 63 selects the manual mode, it is rotated from the zero position button 6354 to be connected to the second switch circuit 6353. When the start button 6357 is pressed, the normally open contact 6358 closes, the second switch circuit 6353 is energized, and the first signal lamp 637 lights up, indicating that the device is powered on. When the stop button 6356 is pressed, the normally open contact 6358 opens, the second switch circuit 6353 is de-energized, and the first signal lamp 637 goes out, indicating that the device is powered off.

[0097] Embodiment 3

[0098] Compared with Embodiment 2, most of them are the same, except that the external circulation self-heating device further includes a second circulation pump 7 located between the liquid return port 13 and the external circulation pipeline 3. The first circulation pump 2 at the liquid outlet 12 pumps the hydraulic oil in the fuel tank 1 into the external circulation pipeline 3 and then returns it to the liquid return port 13. The second circulation pump 7 is used to improve the power of the external circulation of the hydraulic oil, ensuring that the hydraulic oil in the external circulation pipeline 3 can completely return to the fuel tank 1 without being blocked or accumulated due to the shape of the external circulation pipeline 3, as Figure 4 shown.

[0099] In this embodiment, the second circulation pump 7 is connected to the control box 6, and the second circulation pump 7 is connected to the first circuit 61 and works or stops working together with the first circulation pump 2.

[0100] The above description of the embodiments is provided to enable those of ordinary skill in the art to understand and use the utility model. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present utility model is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present utility model according to the disclosure of the present utility model should be within the protection scope of the present utility model.

Claims

1. A hydraulic oil external circulation self-heating device for heating the hydraulic oil in a fuel tank (1), the fuel tank (1) comprising a tank body (11) and a liquid outlet (12) and a liquid return port (13) connected thereto, characterized in that, The external circulation self-heating device includes: A first circulation pump (2) connected to the liquid outlet (12) and used to extract the hydraulic oil in the fuel tank (1); An external circulation pipeline (3) connected to the first circulation pump (2) and the liquid return port (13); And an electric heating component (4) connected to the outer wall of the external circulation pipeline (3).

2. The self-heating device for external circulation of hydraulic oil according to claim 1, characterized in that The external circulation pipeline (3) includes: A first connecting pipe (31) connected to the first circulation pump (2); A second connecting pipe (32) connected to the liquid return port (13); A serpentine pipeline (33) with both ends respectively connected to the first connecting pipe (31) and the second connecting pipe (32).

3. The self-heating device with external circulation of hydraulic oil according to claim 2, characterized in that, The electric heating component (4) is arranged on the outer wall of the serpentine pipeline (33) or between adjacent straight pipes of the serpentine pipeline (33).

4. A hydraulic oil external circulation self-heating device according to claim 1, characterized in that The electric heating component (4) includes a single-head electric heating rod, an electric heating tube, an electric heating plate, and an electric heating sheet.

5. A hydraulic oil external circulation self-heating device according to claim 1, characterized in that, The external circulation self-heating device further includes a second circulation pump (7) located between the liquid return port (13) and the external circulation pipeline (3).

6. A hydraulic oil external circulation self-heating device according to claim 1, characterized in that A temperature sensor (5) is arranged between the liquid outlet (12) and the first circulation pump (2).

7. A hydraulic oil external circulation self-heating device according to claim 6, characterized in that, The external circulation self-heating device further includes a control box (6) connected to a power supply, which is connected to the temperature sensor (5), the electric heating component (4), and the first circulation pump (2).

8. The self-heating device for external circulation of hydraulic oil according to claim 7, characterized in that, The control box (6) includes: A first circuit (61) with both ends respectively connected to the first circulation pump (2) and the live wire (64); A second circuit (62) with both ends respectively connected to the electric heating component (4) and the first circuit (61), and the electric heating component (4) is also connected to the neutral wire (65); A third circuit (63) with both ends respectively connected to the temperature sensor (5) and the first circuit (61) and simultaneously controlling the connection or disconnection of the first circuit (61) and the second circuit (62); And a grounding wire (66).

9. The self-heating device for external circulation of hydraulic oil according to claim 8, wherein The third circuit (63) includes a thermostat (631), a thermostat thermal open contact (632), an intermediate relay coil (633), a contactor coil (634), and a switch assembly (635) connected in series with the temperature sensor (5) by wires in sequence. The switch assembly (635) includes a control selection switch (6351) and a first switch circuit (6352), a second switch circuit (6353), and a zero-position button (6354) connected to it by wires. The first switch circuit (6352), the second switch circuit (6353), and the zero-position button (6354) are in parallel.

10. A hydraulic oil external circulation self-heating device according to claim 9, characterized in that, A contactor normally open contact (611) is arranged on the first circuit (61) between the connection point of the first circuit (61) and the second circuit (62) and the connection point of the first circuit (61) and the third circuit (63); An intermediate relay normally open contact (6355) is arranged on the first switch circuit (6352). A stop button (6356) and a start button (6357) are connected in series on the second switch circuit (6353), and a normally open contact (6358) is connected in parallel with the start button (6357).

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