Circulating cooling water system for multi-pump combined operation

Abstract

The utility model discloses a circulating cooling water system for multi-pump combined operation. The circulating cooling water system comprises a plurality of water supply branch pipelines, a variable frequency water pump is arranged on one water supply branch pipeline, and power frequency water pumps are arranged on the other water supply branch pipelines; one end of each water supply branch pipeline is connected with the water supply main pipe, the water supply main pipe is connected with the tail end heat dissipation equipment, and the other ends of the water supply branch pipelines are connected with the water outlet ends of the cooling towers respectively; the water inlet ends of the cooling towers are connected with the water return main pipe, and the water return main pipe is connected with the tail end heat dissipation equipment; a pressure transmitter is mounted on the water supply main pipe; the output end of the pressure transmitter is connected with the signal input end of the frequency converter, and the control end of the frequency converter is connected with the variable-frequency water pump. The water supply pressure and the water supply flow can be effectively adjusted by arranging one variable frequency water pump and a plurality of power frequency water pumps for combined operation, the mode of directly adopting a valve for adjustment is avoided, the energy consumption of the circulating cooling water system is reduced, and stable operation of the system is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of circulating cooling water systems, in particular to a circulating cooling water system jointly operated by a plurality of water pumps. Background Art

[0002] Circulating cooling water systems are widely used in metallurgy, chemical industry, power generation, pharmaceutical and other industries, and are an essential basic configuration in industrial production. When designing a circulating cooling water system, the water pump is usually selected based on the most unfavorable operating conditions throughout the year and a certain safety factor. During the operation of the system, the water pump has a "large flow, small head" phenomenon, and the water supply pressure cannot meet the actual demand. In order to solve this problem, the company increases the water supply pressure by closing the valve opening, but the closing of the valve opening increases the resistance of the pipe network, resulting in increased energy consumption, and may cause the water supply flow to fail to meet the actual demand.

[0003] In addition, when selecting water pumps, enterprises use all industrial frequency water pumps in order to reduce investment. The water pumps operate under rated conditions throughout the year. When factors such as seasons and ambient temperature change, the flow of cooling water cannot be changed by adjusting the industrial frequency water pumps, resulting in excessive water pressure and a flow rate that is higher than the flow rate that meets the load demand for a long time, causing energy waste. In order to save resources, enterprises reduce the cooling water flow rate by closing the opening of the pipe network valve. Although this method can reduce the flow rate of the system, it also increases the water pressure. Not only can it not effectively control the flow rate, but it also increases the resistance of the pipe network and increases the energy consumption of the industrial frequency water pump.

[0004] Aiming at the problem that the existing circulating cooling water system will lead to increased energy consumption and energy waste when adjusting the flow or pressure, the utility model designs a circulating cooling water system with multiple pumps operating in combination. Utility Model Content

[0005] In view of the problem that the flow rate or pressure of a circulating cooling water system is increased and energy is wasted by adjusting the flow rate or pressure of the circulating cooling water system by the valve opening in the prior art, the utility model provides a circulating cooling water system with multiple pumps operating in combination, including: multiple water supply branch pipelines; a variable frequency water pump is arranged on one of the water supply branch pipelines, and industrial frequency water pumps are arranged on the other water supply branch pipelines; one end of each water supply branch pipeline is connected to a water supply main pipeline, which is connected to a terminal heat dissipation device, and the other ends of the multiple water supply branch pipelines are respectively connected to the water outlet ends of multiple cooling towers; the water inlet ends of the multiple cooling towers are connected to a return water main pipeline, which is connected to the terminal heat dissipation device; a pressure transmitter is installed on the water supply main pipeline; the output end of the pressure transmitter is connected to the signal input end of the frequency converter, and the control end of the frequency converter is connected to the variable frequency water pump; by equipping a variable frequency water pump and operating in combination with multiple industrial frequency water pumps, the water supply pressure and water supply flow rate can be effectively adjusted, avoiding the direct use of valve adjustment, reducing the energy consumption of the circulating cooling water system, and ensuring that the system can operate stably.

[0006] Preferably, there are two water supply branch pipes, namely water supply branch pipe 1 and water supply branch pipe 2; the water supply main pipe is connected to one end of water supply branch pipe 1 and water supply branch pipe 2, and the water supply main pipe is connected to the terminal heat dissipation equipment; the other end of water supply branch pipe 1 is connected to the water outlet of the first cooling tower; valve 1, power frequency water pump, and valve 2 are installed on the water supply branch pipe 1 in sequence; valve 1 and valve 2 are used for regulating the inlet and outlet water flow of the first power frequency water pump or for equipment maintenance; check valve 1 can prevent water backflow in the water supply main pipe; the other end of water supply branch pipe 2 is connected to the water outlet of the second cooling tower; valves are installed on the water supply branch pipe 2 in sequence Door three, variable frequency water pump, valve four; valve three and valve four are used for regulating the inlet and outlet water flow of the variable frequency water pump or for equipment maintenance; a pressure transmitter is installed on the water supply main, the output end of the pressure transmitter is connected to the signal input end of the frequency converter, and the control end of the frequency converter is connected to the variable frequency water pump; the water inlet end of the first cooling tower is connected to the return water main through valve five, and the return water main is connected to the terminal heat dissipation equipment; the water inlet end of the second cooling tower is connected to the return water main through valve six, and the return water main is connected to the terminal heat dissipation equipment; valve five and valve six are used to regulate the water inlet flow entering the first cooling tower and the second cooling tower respectively.

[0007] Preferably, a check valve 1 is arranged on the water supply branch pipe 1, and a check valve 2 is arranged on the water supply branch pipe 2; this can prevent the water in the water supply main pipe from flowing back.

[0008] Preferably, the water inlet and outlet ends of the variable frequency water pump are respectively provided with pressure gauge three and pressure gauge four, which are used to monitor the water inlet and outlet pressures of the variable frequency water pump; the water inlet and outlet ends of the first working frequency water pump are respectively provided with pressure gauge one and pressure gauge two, which are used to monitor the water inlet and outlet pressures of the first working frequency water pump.

[0009] Preferably, the output end of the pressure transmitter is also connected to a pressure alarm, which sounds an alarm when the pressure is too high or too low.

[0010] Preferably, the valve five is an electrically controlled valve; the upper limit alarm output end of the pressure alarm is electrically connected to the control end of the AC contactor KM2 through the time relay KT2; the lower limit alarm output end of the pressure alarm is electrically connected to the control end of the AC contactor KM1 through the time relay KT1; one end of the normally closed contact of the AC contactor KM2 is connected to the AC power supply, and the other end is electrically connected to one end of the normally open contact of the AC contactor KM1, and the other end of the normally open contact of the AC contactor KM1 is electrically connected to the control end of the time relay KT1, the power supply end of the first industrial frequency water pump, and the control end of the valve five.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1) Compared with the conventional circulating cooling water system that uses all industrial frequency water pumps, the utility model is equipped with a variable frequency water pump and multiple industrial frequency water pumps to operate jointly, which can effectively adjust the water supply pressure and water supply flow, avoid directly using valve adjustment, reduce the energy consumption of the circulating cooling water system, and ensure the stable operation of the system.

[0013] 2) For a circulating cooling water system equipped with multiple water pumps, compared with all water pumps using variable frequency water pumps and variable frequency control, the utility model uses multiple industrial frequency water pumps and one variable frequency water pump for control, which reduces the company's investment while ensuring energy-saving effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the first embodiment of the utility model;

[0015] Figure 2 It is a structural schematic diagram of the second embodiment of the utility model;

[0016] Figure 3 It is a structural schematic diagram of the third embodiment of the utility model. DETAILED DESCRIPTION

[0017] The following will be combined with the attached embodiment of the present utility model Figure 1-3 ; Clearly and completely describe the technical solutions in the embodiments of the utility model:

[0018] like Figure 1As shown, in the first embodiment of the utility model, a circulating cooling water system with multiple pumps in joint operation includes: a first cooling tower 1, a second cooling tower 27, a first power frequency water pump 4, a variable frequency water pump 12, a frequency converter 19, and a terminal heat dissipation device 26; the water supply main 24 is connected to one end of the water supply branch pipe 1 7 and the water supply branch pipe 2 17, and the terminal heat dissipation device 26 is connected to the water supply main 24; the other end of the water supply branch pipe 1 7 is connected to the water outlet end of the first cooling tower 1; the water supply branch pipe 1 7 is connected to the water outlet end of the first cooling tower 1; the water supply branch pipe 1 7 is connected to the water outlet end of the first cooling tower 1; the water supply branch pipe 1 A valve 2, a power frequency water pump 4, a valve 2 6, and a check valve 8 are installed in sequence; the valve 2 and the valve 2 6 are used for regulating the inlet and outlet water flow of the first power frequency water pump 4 or for equipment maintenance; the check valve 8 can prevent the water in the water supply main 24 from flowing back; the water inlet and outlet ends of the first power frequency water pump 4 are respectively provided with a pressure gauge 3 and a pressure gauge 2 5 for monitoring the inlet and outlet pressures of the first power frequency water pump 4; the other end of the water supply branch pipe 2 17 is connected to the outlet end of the second cooling tower 27; the water supply branch pipe 2 17 The valve 3 10, the variable frequency water pump 12, the valve 4 16, and the check valve 2 18 are sequentially installed on the water supply pipe 24; the valve 3 10 and the valve 4 16 are used for regulating the water flow in and out of the variable frequency water pump 12 or for equipment maintenance; the check valve 2 18 can prevent the water in the water supply pipe 24 from flowing back; the water inlet and outlet ends of the variable frequency water pump 4 are respectively provided with a pressure gauge 3 11 and a pressure gauge 4 13 for monitoring the water inlet and outlet pressures of the variable frequency water pump 4; the water supply pipe 24 is provided with a pressure transmitter 23, and the output of the pressure transmitter 23 The end is connected to the signal input end of the frequency converter 19, and the control end of the frequency converter 19 is connected to the variable frequency water pump 12; the water inlet end of the first cooling tower 1 is connected to the return water main pipe 25 through the valve five 9, and the return water main pipe 25 is connected to the terminal heat dissipation device 26; the water inlet end of the second cooling tower 27 is connected to the return water main pipe 25 through the valve six 28, and the return water main pipe 25 is connected to the terminal heat dissipation device 26; the valve five 9 and the valve six 28 are used to adjust the water inlet flow entering the first cooling tower 1 and the second cooling tower 27 respectively.

[0019] During specific implementation, the first industrial frequency water pump 4 and the variable frequency water pump 12 are jointly operated, and the first industrial frequency water pump 4 and the variable frequency water pump 12 are designed and selected according to the requirements of the design flow and design head, and taking into account the actual pipe network resistance curve and the water pump performance curve; during operation, the pressure of the water supply main 24 is monitored in real time by the pressure transmitter 23, and the pressure signal is transmitted to the frequency converter 19. When the pressure of the water supply main 24 does not meet the system requirements, the frequency converter 19 automatically controls the variable frequency water pump 12 to pressurize, so as to avoid the problem of reduced water flow after increasing the water supply pressure by closing the valve opening; when the pressure of the water supply main 24 is too high and the water flow is too large, the frequency converter 19 automatically controls the variable frequency water pump 12 to reduce the pressure, so as to avoid the problem of increased pipe network resistance and increased pump energy consumption after reducing the water flow by closing the valve opening; so that the water flow pressure in the water supply main 24 remains constant.

[0020] like Figure 2 As shown, in the second embodiment of the utility model, compared with the first embodiment, a water supply branch pipe 3 30 and a third cooling tower 31 are added; one end of the water supply branch pipe 3 30 is connected to the water supply main pipe 24; the other end of the water supply branch pipe 3 30 is connected to the water outlet of the third cooling tower 31; the water supply branch pipe 3 30 is sequentially installed with a valve 7 33, a second power frequency water pump 29, a valve 8 36, and a check valve 3 37; the valve 7 33 and the valve 8 36 are used for regulating the inlet and outlet water flow of the power frequency water pump 4 or for equipment maintenance; the check valve 3 37 can prevent the water in the water supply main pipe 24 from flowing back; the water inlet and outlet ends of the second power frequency water pump 29 are respectively provided with a pressure gauge 5 34 and a pressure gauge 6 35 for the inlet and outlet pressure of the second power frequency water pump 29; the water inlet end of the third cooling tower 31 is connected to the return water main pipe 25 through a valve 9 32, and the return water main pipe 25 is connected to the terminal heat dissipation device 26.

[0021] The above scheme is applied to the occasion where two power frequency pumps work together, and the water pressure is controlled by the variable frequency water pump 12, and the water pressure is adjusted under the condition that the branch pipe network where the power frequency pump is located is not affected. In addition, the above scheme can be extended to the occasion where more than two power frequency pumps work together.

[0022] like Figure 3 As shown, in the third embodiment of the utility model, compared with the first embodiment, the difference is that the valve 5 9 adopts an electrically controlled valve; the output end of the pressure transmitter 23 is also connected to the pressure alarm 22, and the upper limit alarm output end of the pressure alarm 22 is electrically connected to the control end of the AC contactor KM2 through the time relay KT2; the lower limit alarm output end of the pressure alarm 22 is electrically connected to the control end of the AC contactor KM1 through the time relay KT1; one end of the normally closed contact of the AC contactor KM2 is connected to the AC power supply, and the other end is electrically connected to one end of the normally open contact of the AC contactor KM1, and the other end of the normally open contact of the AC contactor KM1 is electrically connected to the control end of the time relay KT1, the power supply end of the first industrial frequency water pump 4, and the control end of the valve 5 9 respectively.

[0023] When the above scheme is in operation, the first power frequency water pump 4 is in standby mode. When the pressure of the water supply main 24 does not meet the system demand, the frequency converter 19 automatically controls the variable frequency water pump 12 to increase the pressure. After the variable frequency water pump 12 increases the pressure, if the pressure still cannot meet the demand, that is, after the lower limit alarm of the pressure alarm 22 is output, after a certain period of time, the lower limit alarm is still not released, then the time relay KT1 is actuated to control the normally open contact of the AC contactor KM1 to close, the first power frequency water pump 4 is powered on and started, the valve 5 9 is opened, and the time relay KT1 is self-locked, and the first The power frequency water pump 4 is put into operation; when the first power frequency water pump 4 and the variable frequency water pump 12 are working at the same time, when the pressure of the water supply main 24 is higher than the system demand, the frequency converter 19 automatically controls the variable frequency water pump 12 to reduce the pressure. After the pressure is reduced by the variable frequency water pump 12, the pressure is still too high, that is, after the upper limit alarm of the pressure alarm 22 is output, after a certain period of time, the upper limit alarm is still not released, then the time relay KT2 is activated to control the normally closed contact of the AC contactor KM2 to disconnect, the first power frequency water pump 4 is powered off, the valve 5 9 is closed, and the time relay KT1 is powered off. The above scheme designs the first power frequency water pump 4 as a standby water pump, improves the adaptability of the circulating cooling water system, and can be used in occasions where the demand for cooling water varies greatly.

[0024] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention based on the technical solution and improved concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A circulating cooling water system with multiple pumps operating in combination, comprising: Multiple water supply branch pipelines; characterized in that: a variable frequency water pump is arranged on one of the water supply branch pipelines, and industrial frequency water pumps are arranged on the other water supply branch pipelines; one end of each water supply branch pipeline is connected to a water supply main pipeline, which is connected to a terminal heat dissipation device, and the other ends of the multiple water supply branch pipelines are respectively connected to water outlets of multiple cooling towers; the water inlet ends of the multiple cooling towers are connected to a return water main pipeline, which is connected to the terminal heat dissipation device; a pressure transmitter is installed on the water supply main pipeline; the output end of the pressure transmitter is connected to the signal input end of the frequency converter, and the control end of the frequency converter is connected to the variable frequency water pump.

2. A circulating cooling water system with multiple pumps operating in combination according to claim 1, characterized in that: There are two water supply branch pipes, namely water supply branch pipe 1 and water supply branch pipe 2; the water supply main pipe is connected to one end of water supply branch pipe 1 and water supply branch pipe 2, and the water supply main pipe is connected to the terminal heat dissipation equipment; the other end of water supply branch pipe 1 is connected to the water outlet of the first cooling tower; valve 1, industrial frequency water pump and valve 2 are installed on water supply branch pipe 1 in sequence; the other end of water supply branch pipe 2 is connected to the water outlet of the second cooling tower; valve 3, variable frequency water pump and valve 4 are installed on water supply branch pipe 2 in sequence; the water inlet end of the first cooling tower is connected to the return water main pipe through valve 5, and the return water main pipe is connected to the terminal heat dissipation equipment; the water inlet end of the second cooling tower is connected to the return water main pipe of the terminal heat dissipation equipment through valve 6.

3. A circulating cooling water system with multiple pumps operating in combination according to claim 2, characterized in that: The first water supply branch pipe is provided with a first check valve, and the second water supply branch pipe is provided with a second check valve.

4. A circulating cooling water system with multiple pumps operating in combination according to claim 2, characterized in that: The water inlet and outlet ends of the variable frequency water pump are respectively provided with pressure gauge three and pressure gauge four; the water inlet and outlet ends of the first working frequency water pump are respectively provided with pressure gauge one and pressure gauge two.

5. The circulating cooling water system with multiple pumps operating in combination according to claim 2 is characterized in that: The output end of the pressure transmitter is also connected to a pressure alarm.

6. A circulating cooling water system with multiple pumps operating in combination according to claim 5, characterized in that: The valve five is an electrically controlled valve; the upper limit alarm output end of the pressure alarm is electrically connected to the control end of the AC contactor KM2 through the time relay KT2; the lower limit alarm output end of the pressure alarm is electrically connected to the control end of the AC contactor KM1 through the time relay KT1; one end of the normally closed contact of the AC contactor KM2 is connected to the AC power supply, and the other end is electrically connected to one end of the normally open contact of the AC contactor KM1, and the other end of the normally open contact of the AC contactor KM1 is electrically connected to the control end of the time relay KT1, the power supply end of the first industrial frequency water pump, and the control end of the valve five.

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