Preheating system for heat distribution pipeline construction

Abstract

The utility model discloses a preheating system for heat distribution pipeline construction, which comprises a power supply, an insulating air pipe, a communicating air pipe and a temperature monitoring unit, one pipe orifice of the insulating air pipe is connected with a first pipe orifice of a water supply preheating pipe, the other pipe orifice of the insulating air pipe is connected with a first pipe orifice of a water return preheating pipe, and a circulating fan is arranged on the insulating air pipe; one pipe orifice of the communicating pipe is connected with the second pipe orifice of the water supply preheating pipe, the other pipe orifice of the communicating pipe is connected with the second pipe orifice of the return water preheating pipe, and the communicating pipe electrically connects the water supply preheating pipe with the return water preheating pipe; the water supply preheating pipe, the insulating air pipe, the return water preheating pipe and the communicating air pipe form an air circulation loop. The water supply preheating pipe and the return water preheating pipe are electrically connected through the communicating air pipe to form an electric conductor, the water supply preheating pipe and the return water preheating pipe form an air circulation loop through the insulating air pipe and the communicating air pipe, air is in a circulation state all the time during preheating, the temperature of the hot water preheating pipe and the temperature of the return water preheating pipe are balanced as much as possible, and the temperature difference is reduced.

Description

Technical Field

[0001] This utility model relates to the field of thermal pipeline construction, and in particular to a preheating system for thermal pipeline construction. Background Technology

[0002] When transporting hot water or steam, the temperature of heating pipelines undergoes drastic changes. Without preheating, a significant temperature difference will occur between the pipeline's operating and installed states after the hot medium enters. Due to the thermal expansion and contraction properties of metallic materials, this temperature difference will cause thermal stress and axial thrust within the pipeline, thus affecting its safe operation. Therefore, large-diameter heating pipelines typically require preheating before operation. Preheating reduces the magnitude of thermal stress and axial thrust by half, and also reduces the thrust on tees, valves, and other joints by half, improving pipeline operational safety.

[0003] Electric preheating pipeline installation technology involves energizing a preheating section of pipeline of a certain length within a trench. Due to the inherent resistance of steel pipelines, they heat up and expand when current is applied, generating tensile stress. Once the pipeline has been preheated to the required temperature and the required elongation has been achieved, the trench is backfilled. In the laying of heating pipelines, both the supply and return water pipelines participate in the preheating process because they form an electrical circuit.

[0004] Currently, preheating during the laying of heating pipelines utilizes the electrical conductivity of the metal lining of the preheating pipe section. The working pipes of both the supply and return water preheating sections are connected to a power source, and the working pipes heat the water using resistance heating. However, the thinner wall of the return water preheating pipe results in relatively high resistance and a rapid heating rate. By the time the supply water preheating pipe reaches its preheating temperature, the return water preheating pipe has already exceeded its set preheating temperature, sometimes even exceeding the allowable temperature, failing to meet actual needs and consuming excessive energy. Utility Model Content

[0005] In view of this, the present invention proposes a preheating system for the construction of thermal pipelines, which can make the temperature of the two preheating pipes as uniform as possible through air flow, thereby reducing the temperature difference.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The preheating system for thermal pipeline construction described in this utility model includes a power supply with a power on / off switch, an insulated air duct, a connecting air duct, and a temperature monitoring unit. One port of the insulated air duct is connected to the first port of the water supply preheating pipe, and the other port of the insulated air duct is connected to the first port of the return water preheating pipe. The circulating fan is installed on the insulated air duct, and the fan cable of the circulating fan is electrically connected to the power supply.

[0008] One port of the connecting duct is connected to the second port of the water supply preheating pipe, and the other port is connected to the second port of the return water preheating pipe. The connecting duct is an insulated pipe containing a connecting cable, and the connecting cable inside the connecting duct electrically connects the water supply preheating pipe and the return water preheating pipe.

[0009] The temperature monitoring unit includes a controller, a first temperature monitoring element installed in the water supply preheating pipe, and a second temperature monitoring element installed in the water return preheating pipe. The signal output terminals of the first and second temperature monitoring elements are connected to the signal input terminal of the controller.

[0010] The water supply preheating pipe, the insulating air duct, the return water preheating pipe, and the connecting air duct are connected end to end to form an air circulation loop; the first pipe openings of the water supply preheating pipe and the return water preheating pipe are electrically connected to the power supply through preheating cables.

[0011] Preferably, the circulating fan is installed on an insulated duct near the water supply preheating pipe.

[0012] Compared with the prior art, the advantages of this utility model are as follows: This utility model uses a connecting ventilation duct to electrically connect the water supply preheating pipe and the return water preheating pipe, thereby forming a conductor. This conductor is connected to a power source through a preheating cable to achieve electric heating. During the heating process, the water supply preheating pipe and the return water preheating pipe form an air circulation loop through the insulated air duct and the connecting ventilation duct. The power provided by the circulating fan keeps the air in the loop in a continuous state of circulation, so that the temperature of the hot water preheating pipe and the return water preheating pipe is as balanced as possible, reducing the temperature difference between the water supply preheating pipe and the return water preheating pipe, and ensuring that the preheating temperature of both pipes is within the design range. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0014] The embodiments of this utility model will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of this utility model and provide detailed implementation methods and specific operation processes. However, the protection scope of this utility model is not limited to the following embodiments.

[0015] It should be noted that in the description of this utility model, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0016] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0017] like Figure 1 As shown, this utility model proposes a preheating system for thermal pipeline construction, including a power supply 1 with a power on / off switch, an insulated duct 2, a connecting duct 3, and a temperature monitoring unit. One port of the insulated duct 2 is connected to the first port of the water supply preheating pipe 4, and the other port of the insulated duct 2 is connected to the first port of the return water preheating pipe 5. A circulating fan 6 is installed on the insulated duct 2 (close to the water supply preheating pipe 4). The fan cable 8 of the circulating fan 6 (a conductor covered with an insulating sheath, such as copper wire, aluminum wire, etc.) is electrically connected to the power supply 1. The circulating fan 6 can provide power to promote airflow.

[0018] One port of the connecting ventilation pipe 3 is connected to the second port of the water supply preheating pipe 4, and the other port is connected to the second port of the return water preheating pipe 5. The connecting ventilation pipe 3 is an insulated pipe. A connecting cable is installed inside the connecting ventilation pipe 3 to electrically connect the water supply preheating pipe 4 and the return water preheating pipe 5.

[0019] The temperature monitoring unit includes a controller, a first temperature monitoring element installed in the water supply preheating pipe 4, and a second temperature monitoring element installed in the return water preheating pipe 5. The signal output terminals of the first and second temperature monitoring elements are connected to the signal input terminals of the controller to monitor the air temperature in the water supply preheating pipe 4 and the return water preheating pipe 5, respectively. The water supply preheating pipe 4, the insulating air duct 2, the return water preheating pipe 5, and the connecting air duct 3 are connected end to end to form an air circulation loop. During the preheating process, the air can circulate and promote balance. The first pipe openings of the water supply preheating pipe 4 and the return water preheating pipe 5 are electrically connected to the power supply 1 through the preheating cable 7.

[0020] During actual installation, first install the water supply preheating pipe 4 and the return water preheating pipe 5 into place, then install temperature monitoring devices in the water supply preheating pipe 4 and the return water preheating pipe 5 respectively, then install the connecting ventilation pipe 3, the insulating air pipe 2, and the circulating fan 6 respectively, and finally connect the circulating fan 6, the temperature monitoring device, and the preheating cable 7 to the power supply 1 respectively.

[0021] During preheating, turn on the power switch 1 to energize the circulating fan 6 and the preheating pipe. The preheating pipe generates heat and heats the air. The power provided by the circulating fan 6 causes the air to flow in the air circulation loop. This circulation can achieve temperature balance between the water supply preheating pipe 4 and the return water preheating pipe 5, reduce the temperature difference between the water supply preheating pipe 4 and the return water preheating pipe, ensure that the preheating temperature of both preheating pipes is within the design range, reduce the temperature stress amplitude and axial thrust inside the pipe, and meet the requirements for safe operation of the pipe.

[0022] After preheating, turn off the power switch to de-energize the water supply preheating pipe 4, the return water preheating pipe 5, and the circulating fan 6. Remove the insulated air duct 2, the circulating fan 6, and the connecting air duct 3. Connect the water supply preheating pipe 4 to the other sections of the water supply pipeline to complete the laying of the water supply pipeline. Connect the return water preheating pipe 5 to the other sections of the return water pipeline to complete the laying of the return water pipeline.

[0023] This utility model utilizes a connecting ventilation duct 3 to electrically connect the water supply preheating pipe 4 and the return water preheating pipe 5, thereby forming a conductor. This conductor is connected to the power supply 1 through a preheating cable 7, enabling electric heating. During the heating process, the water supply preheating pipe 4 and the return water preheating pipe 5 form an air circulation loop through the insulated air duct 2 and the connecting ventilation duct 3. The power provided by the circulating fan 6 keeps the air in a continuous state of circulation, thereby achieving heat balance and preventing the temperature of the return water preheating pipe from becoming too high and deviating significantly from the design temperature.

[0024] In actual installation, the controller and power supply 1 can be integrated together. Power supply 1 uses a battery to provide power to the circulating fan 6, the controller, and the two temperature monitoring devices. Alternatively, if an external power supply 1 is available at the construction site, the power supply 1 of this invention can be connected to the site's power supply 1 via a power supply line. Furthermore, the two temperature monitoring devices of this invention can also be wireless temperature sensors.

[0025] In actual installation, the controller of this utility model can be a general-purpose processor, a special-purpose processor, a conventional processor, a digital signal processor (DSP), multiple microprocessors, one or more microprocessors associated with the DSP core, a controller, a microcontroller, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) circuit, any other type of integrated circuit (IC), a state machine, and a PLC controller, etc.

[0026] Finally, it should be emphasized that the above description is merely a preferred embodiment of this utility model and is not intended to limit this utility model. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A preheating system for thermal pipeline construction, comprising a power supply with a power on / off switch, characterized in that: It also includes an insulated air duct, a connecting air duct, and a temperature monitoring unit. One port of the insulated air duct is connected to the first port of the water supply preheating pipe, and the other port of the insulated air duct is connected to the first port of the return water preheating pipe. A circulating fan is installed on the insulated air duct, and the fan cable of the circulating fan is electrically connected to the power supply. One port of the connecting duct is connected to the second port of the water supply preheating pipe, and the other port is connected to the second port of the return water preheating pipe. The connecting duct is an insulated pipe containing a connecting cable, and the connecting cable inside the connecting duct electrically connects the water supply preheating pipe and the return water preheating pipe. The temperature monitoring unit includes a controller, a first temperature monitoring element installed in the water supply preheating pipe, and a second temperature monitoring element installed in the water return preheating pipe. The signal output terminals of the first and second temperature monitoring elements are connected to the signal input terminal of the controller. The water supply preheating pipe, the insulating air duct, the return water preheating pipe, and the connecting air duct are connected end to end to form an air circulation loop; the first pipe openings of the water supply preheating pipe and the return water preheating pipe are electrically connected to the power supply through preheating cables.

2. The preheating system for thermal pipeline construction according to claim 1, characterized in that: The circulating fan is installed on an insulated duct near the water supply preheating pipe.

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