Temperature-adjusting circulating water system for PVC-O pipes

Abstract

The utility model discloses a temperature adjusting circulating water system for PVC-O pipes, and relates to the technical field of circulating water systems, the temperature adjusting circulating water system comprises a circulating water pool, a water cooling tower, a refrigerating unit and a water feeding pump, the circulating water system comprises a basic cycle and a cooling cycle, and the upstream of the circulating water pool is connected with a water return pool; a control valve is arranged on a communication pipeline between the water return pool and the circulating water pool, a communication pipeline between the to-be-cooled equipment and the water return pool is a water return pipeline, and a first temperature transmitter is arranged on the water return pipeline and used for feeding back and controlling the flow ratio of circulating water entering the basic circulation and the cooling circulation; the cooling circulation comprises medium-low-temperature circulation and low-temperature circulation, the medium-low-temperature circulation comprises the step that circulating water is cooled through a water cooling tower, and the low-temperature circulation comprises the step that the circulating water is cooled through a refrigerating unit. According to the circulating water system, different temperature control schemes and process routes can be adopted according to different working conditions, and the production quality and the yield of PVC-O pipes are improved.

Description

Technical Field

[0001] The present application belongs to the technical field of PVC-O pipe processing, and specifically, to the technical field of circulating water systems in the production and manufacturing of PVC-O pipes. Background Art

[0002] PVC (polyvinyl chloride) is the second largest plastic after PE (polyethylene). It has stable physical and chemical properties, large output, low price, and is widely used in various fields of life. PVC-O pipes made of PVC as raw material through a special orientation processing technology are a new type of PVC pipe with high strength, high toughness, high impact resistance and fatigue resistance.

[0003] The PVC-U pipe produced by the extrusion method is stretched axially and radially to make the PVC long-chain molecules in the pipe arranged regularly in the biaxial direction. The production process includes mixing, extrusion, shaping, cooling, cutting, oven heating, orientation, secondary cooling, cutting, expansion and other processes, and finally the PVC-O finished pipe is manufactured. The technical difficulty in the production process of PVC-O pipe is to control the cooling temperature of extrusion, shaping, cooling, orientation, secondary cooling and expansion, especially the temperature control of orientation, secondary cooling and expansion. Too high or too low temperature will affect the product quality and energy consumption of PVC-O pipe. If the temperature is too high, the main body of the extruder will heat up too quickly, and the pipe in the extruder may be too plasticized or even decomposed; the temperature of the vacuum sizing machine is high, which will cause large fluctuations in the diameter of the pipe; the orientation temperature is high, and there will be problems with the orientation degree and hydrostatic pressure of the pipe, and the pipe may crack in severe cases; the temperature of the cooling spray water tank is high, and the pipe shrinks greatly; the cooling temperature of the expansion machine is high, which affects the high molecular orientation of PVC, reduces the tensile strength of the pipe, and deteriorates the hydrostatic performance.

[0004] The conventional cooling method is to use circulating water cooling. The circulating water system mainly includes circulating water pumps, cooling towers, pools and other equipment and facilities. Due to the large difference in temperature throughout the year across the country, the highest temperature can reach above 45°C and the lowest temperature can be as low as below -30°C. The cooling temperature of the conventional circulating water system fluctuates according to the change of ambient temperature. In the summer, due to the excessive heat, the temperature of the circulating water is as high as above 35°C, which cannot achieve a good cooling effect and cannot meet the process requirements, resulting in large fluctuations in the quality of PVC-O pipes, low yield and high energy consumption. However, the industry does not pay much attention to the impact of circulating water temperature on product quality and energy consumption, and has not conducted in-depth research on this aspect.

[0005] The Chinese patent with application number CN201820186919.8 discloses a circulating water treatment device for a PVC pipe production line, providing a water treatment device for filtering and softening circulating water to prevent clogging of nozzles, affecting the normal operation of equipment, and increasing production efficiency. It includes a circulating water pipeline, a water treatment pipeline is arranged in parallel in the water circulation pipeline, a first valve, a processor, and a second valve are arranged on the water treatment pipeline, and the first valve and the second valve are arranged on both sides of the processor. The water circulation pipeline is provided with a water quality detection device at the rear end of the position where the water circulation pipeline and the water treatment pipeline intersect along the direction of water flow, and a reversing valve is provided at the intersection. In this application, by connecting a circulating water treatment device in parallel to the circulating water system of the PVC pipe production line, the circulating cooling water is treated with impurities to prevent the circulating water from clogging the nozzle after taking away impurities. Although the application points out that the processing device is connected in parallel to the circulating water system to treat the circulating water, the application does not point out how to control the temperature of the circulating water to adapt it to the different working conditions of the PVC pipe production equipment.

[0006] The Chinese patent with application number CN201820185443.6 provides a temperature control system that can control the temperature of cooling water to ensure that the water temperature meets the cooling requirements. It is used for cooling the pipes of the vacuum setting machine, including a box body, a water tank is arranged above the box body, a water supply channel is arranged in the box body, the water supply channel is connected to the water tank, and a plurality of nozzles are arranged at the front end of the water supply channel. A recycling water pipeline is also arranged in the box body, and an air-cooled chiller is arranged outside the box body. The recycling water pipeline is connected to the air-cooled chiller, and the outlet of the air-cooled chiller is connected to the water tank to form a circulating water pipeline to reduce resource waste. Although the application proposes to cool the circulating water by temperature monitoring so that the circulating water after temperature control meets the cooling requirements, since the PVC-O pipe is more sensitive to temperature changes, the application simply measures the temperature and cools the circulating water, and does not control the cooling water at a certain temperature for different working conditions.

[0007] The Chinese patent application number CN202222692680.0 discloses a cooling device for reducing the longitudinal shrinkage rate of a pipe, including: a pipe temperature sensor, a cooling water tank, a circulation pipeline, a refrigeration module, a cooling water temperature sensor, a multi-threshold temperature controller and a power supply module, wherein the pipe temperature sensor and the cooling water temperature sensor are electrically connected to the multi-threshold temperature controller respectively; the cooling water tank is connected to the refrigeration module through a circulation pipeline; the multi-threshold temperature controller is electrically connected to the refrigeration module, controls the refrigeration module to generate cooling water and inputs the cooling water tank through the circulation pipeline to cool the pipe, thereby reducing the longitudinal shrinkage rate of the pipe; the device realizes high-precision control of the temperature of the pipe after cooling by step control of the cooling water temperature, thereby maintaining the constant temperature of the pipe during the cooling process, effectively reducing the longitudinal shrinkage rate of the pipe, and at the same time extending the life of the equipment and being more energy-efficient. However, the application is mainly for controlling the longitudinal shrinkage rate of the pipe, so that the pipe can be maintained at 32.3℃~34.3℃ from the time it comes out of the cooling water tank until before cutting, and the adjustable temperature range is relatively narrow. Moreover, for pipes that are greatly affected by the ambient temperature, the circulating water temperature is only adjusted by feedback after measuring the temperature at the pipe outlet of the cooling spray water tank, which cannot effectively control the temperature of other processes in the pipe production. For the water use of other equipment, there is no information on how to adjust the circulating water temperature to adapt to different working conditions.

[0008] In summary, although the above patents all mention the control of circulating water in the PVC pipe production process, none of them adjusts the circulating water system under different temperatures and loads to achieve better cooling effect under different working conditions of pipe production. Summary of the invention

[0009] In view of the use of circulating water to control the cooling temperature of equipment during the production process of PVC-O pipes, the first purpose of the present application is to provide a temperature-regulating circulating water system for PVC-O pipes, which can enable different cooling systems for different working conditions in the production process of PVC-O pipes, thereby saving energy and enabling each device to be cooled to obtain a better cooling effect.

[0010] The second purpose of the present application is to provide a method for using a temperature-regulating circulating water system for PVC-O pipes, which can respectively adopt three different process routes corresponding to three possible ambient temperature conditions, and accurately adjust the inlet temperature of the circulating water according to the specific equipment to be cooled, so that the temperature of the circulating water system has a wide adjustable range and can adapt to various ambient temperatures and the production needs and quality requirements of various models of PVC-O products.

[0011] The technical solution adopted by this application to solve its technical problem is:

[0012] A temperature-regulating circulating water system for PVC-O pipes, comprising: a circulating water pool, a cooling tower, a refrigerating unit and a water supply pump, wherein the circulating water system comprises a basic circulation and a cooling circulation, wherein a return water pool is connected upstream of the circulating water pool, a control valve is arranged on the connecting pipe between the return water pool and the circulating water pool, and a connecting pipe between a device to be cooled and the return water pool is a return water pipe, wherein a first temperature transmitter is arranged on the return water pipe for feedback control of the flow rate ratio of circulating water entering the basic circulation and the cooling circulation; a control valve is arranged on the water supply pump There are three parallel water outlets, namely the first water inlet, the second water inlet and the third water inlet; the above-mentioned basic cycle includes: the above-mentioned return water pool, the above-mentioned circulating water pool, the above-mentioned first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop; the above-mentioned cooling cycle includes: medium and low temperature cycle and low temperature cycle, the above-mentioned medium and low temperature cycle includes: circulating water flows through the above-mentioned second water inlet, and the above-mentioned cooling tower is used to cool the circulating water, and the above-mentioned low temperature cycle includes: circulating water flows through the above-mentioned third water inlet, and the above-mentioned refrigeration unit is used to cool the circulating water.

[0013] Since the quality of PVC-O pipes is greatly affected by temperature, traditional production equipment requires a circulating water system to cool them, but the circulating water system is often unable to autonomously adjust the temperature according to different working conditions. The circulating water system of the present application is provided with a first temperature transmitter at the return water pipe to reflect the cooling temperature required by the equipment to be cooled, and can control the circulating water system to match different cycles to cool the equipment to be cooled according to different working conditions, thereby improving the control accuracy of the circulating water temperature and improving the production quality and uniformity of the product.

[0014] Furthermore, the above-mentioned medium and low temperature cycle includes: the above-mentioned return water pool, the above-mentioned circulating water pool, the above-mentioned second water inlet, the above-mentioned cooling tower, the above-mentioned circulating water pool, the above-mentioned first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop.

[0015] Furthermore, a cooling tower pump is connected in series between the return water tank and the cooling tower, a jacket is provided on the refrigerating unit, and a refrigerator pump is connected in series between the circulating water tank and the jacket; the low-temperature cycle includes: the return water tank, the cooling tower pump, the cooling tower, the circulating water tank, the first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop; the return water tank, the cooling tower pump, the cooling tower, the circulating water tank, the third water inlet, the refrigerating unit and the equipment to be cooled are connected in sequence to form a closed circulation loop; the circulating water tank, the refrigerator pump, the jacket and the cooling tower are connected in sequence to form a closed circulation loop.

[0016] Furthermore, the connecting pipe between the first water inlet and the equipment to be cooled is a normal temperature pipe, and the connecting pipe between the refrigeration unit and the equipment to be cooled is a low temperature pipe.

[0017] Furthermore, a first regulating valve is provided on the above-mentioned normal temperature pipeline; a second regulating valve is provided on the connecting pipeline between the above-mentioned second water inlet and the above-mentioned cooling tower; a third regulating valve is provided on the connecting pipeline between the above-mentioned third water inlet and the above-mentioned refrigeration unit; a first flow transmitter and a second flow transmitter are respectively provided on the above-mentioned low-temperature pipeline and the above-mentioned normal temperature pipeline, which are used for feedback adjustment of the above-mentioned first regulating valve, the above-mentioned second regulating valve and the above-mentioned third regulating valve.

[0018] A method for using a temperature-regulating circulating water system for PVC-O pipes, comprising the following steps:

[0019] S1: Temperature division: The first temperature transmitter monitors the return water temperature of the circulating water system, and controls the flow ratio of the circulating water system entering the basic cycle, the medium and low temperature cycle, and the low temperature cycle according to the temperature conditions.

[0020] S2: Flow control: The flow transmitter is used to feedback and adjust the water outlet flow of the above-mentioned circulating water system.

[0021] S3: Production line control: According to the temperature monitored by the second temperature transmitter, the normal temperature water regulating valve and the low temperature water regulating valve are adjusted to control the flow of circulating water in the normal temperature pipeline and the low temperature pipeline respectively, until the circulating water temperature in the water inlet main pipeline reaches the set value.

[0022] The present application sets a first temperature transmitter on the return pipe of the circulating water system to monitor the return water temperature of the circulating water in real time, and controls the circulating water system to match the actual temperature conditions to enter different cycles, wherein the cooling tower is turned on when matching the medium and low temperature cycles, and the refrigeration unit is turned on when matching the low temperature cycles, so as to match different production conditions with different process routes, achieve high temperature control accuracy, and save energy consumption; a second temperature transmitter is set on the water inlet main pipe, and a separate temperature control point is set for each equipment to be cooled, and the opening of the normal temperature water regulating valve and the low temperature water regulating valve are adjusted by feedback to accurately control the inlet water temperature of the circulating water, thereby improving the production quality, yield rate and production uniformity of the products.

[0023] Compared with the prior art, the embodiments of the present application have at least the following beneficial effects:

[0024] 1. The circulating water system of the present application adopts circulating water of various temperatures, including normal temperature circulating water and low temperature circulating water. By adjusting and controlling the temperature of the circulating water system and analyzing the different temperature requirements of various production equipment in the PVC-O production line for precise control, the uniformity of product quality and the yield rate are improved.

[0025] 2. The circulating water system of the present application realizes the composite control of the circulating water temperature and flow rate, and can independently adopt different process routes according to complex conditions such as actual ambient temperature and production load. The process flow is simple and has extensive applicability, and can effectively solve various cooling problems in the production of PVC-O pipes.

[0026] 3. This application designs monitoring and control points for various equipment and valve instruments in the circulating water system, which improves the utilization rate of the equipment, saves energy consumption, improves production quality and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments and comparative examples will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 This is a process flow chart of the circulating water system of this application.

[0029] Icons: 1-return water pool; 2-circulating water pool; 3-water supply pump; 4-first temperature transmitter; 5-cooling tower; 6-refrigeration unit; 7-normal temperature pipeline; 8-low temperature pipeline; 9-cooling tower pump; 10-refrigeration unit pump; 11-control valve; 12-first regulating valve; 13-second regulating valve; 14-third regulating valve; 15-first flow transmitter; 16-second flow transmitter; 17-normal temperature water regulating valve; 18-low temperature water regulating valve; 19-main water inlet pipeline; 20-second temperature transmitter; 21-return water pipeline; a, b, c correspond to the water flow directions of the first water inlet, the second water inlet and the third water inlet of the water supply pump respectively. DETAILED DESCRIPTION

[0030] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the accompanying drawings can be arranged and designed in various configurations. Those who do not specify specific conditions in the embodiments are carried out according to the conditions recommended by normal conditions or manufacturers. Those who do not specify manufacturers for reagents or instruments used are all conventional products that can be obtained by commercial purchase.

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The technical solution of the present application will be described in detail with reference to specific embodiments.

[0032] A temperature-regulating circulating water system for PVC-O pipes, comprising: a circulating water pool 2, a cooling tower 5, a refrigerating unit 6 and a water supply pump 3, wherein the circulating water system comprises a basic circulation and a cooling circulation, wherein a return water pool 1 is connected upstream of the circulating water pool 2, a control valve 11 is arranged on the connecting pipe between the return water pool 1 and the circulating water pool 2, a return water pipe 21 is a connecting pipe between the equipment to be cooled and the return water pool 1, and a first temperature transmitter 4 is arranged on the return water pipe 21 for feedback control of the flow rate ratio of the circulating water entering the basic circulation and the cooling circulation; The water supply pump 3 is provided with three parallel water outlets, namely the first water supply port, the second water supply port and the third water supply port; the above-mentioned basic cycle includes: the above-mentioned return water tank 1, the above-mentioned circulating water tank 2, the above-mentioned first water supply port and the equipment to be cooled are connected in sequence to form a closed circulation loop; the above-mentioned cooling cycle includes: medium and low temperature cycle and low temperature cycle, the above-mentioned medium and low temperature cycle includes: circulating water flows through the above-mentioned second water supply port, and uses the above-mentioned cooling tower 5 to cool the circulating water, and the above-mentioned low temperature cycle includes: circulating water flows through the above-mentioned third water supply port, and uses the above-mentioned refrigeration unit 6 to cool the circulating water.

[0033] The first temperature transmitter 4 is set on the return pipe 21 of the circulating water system. Since heat exchange has occurred between the circulating water and the equipment to be cooled during the return water, and heat exchange also occurs between the return pipe 21 and the environment, the temperature detected by the first temperature transmitter 4 can be regarded as being affected by the temperature of the equipment to be cooled and the ambient temperature at the same time. According to the possible temperature conditions of the PVC-O pipe production line and the actual needs of the producer, including the influence of factors such as production load, season, geographical location, etc., the circulating water system is divided into basic circulation, medium and low temperature circulation and low temperature circulation, and the first temperature transmitter 4 monitors the temperature in the return pipe 21 and then feedback controls, so that the circulating water system enters the basic circulation, medium and low temperature circulation and low temperature circulation respectively. That is to say, after the first temperature transmitter 4 collects the temperature of the circulating water return water, it can independently determine what temperature of circulating water should be used in the production line at this time, and match different circulations accordingly. For example, in winter or at a high altitude, it is often not necessary to turn on more cooling equipment to cool the circulating water. Then, matching the basic circulation or medium and low temperature circulation can achieve cooling of the equipment in the PVC-O pipe production line, achieve energy saving and environmental protection, and reduce production costs.

[0034] In addition, it should be pointed out that the "equipment to be cooled" mentioned in this application is actually a collective concept. Since the number of production lines is not unique and the production equipment that needs to be cooled in the same production line is not unique, the "equipment to be cooled" mentioned in this article does not refer to a specific equipment, but refers to all the production equipment that needs to be cooled in the production workshop. And because a circulating water system can often supply multiple production lines, each production line and the equipment on each production line can be considered to be connected in parallel to the circulating water system, so it is reasonable to use "equipment to be cooled" here to refer to all the production equipment that needs to be cooled.

[0035] The water supply pump 3 has three water outlets. When the circulating water system enters different cycles, the circulating water flows through different water supply outlets to achieve the circulating water supply to the cooling equipment. It can be understood that whether the three water outlets of the water supply pump 3 are connected in parallel or three pumps are connected in parallel at the water supply end of the circulating water system for water supply, the effect is to make the circulating water flow to different pipes when it is supplied, which belongs to the technical solution of the present application.

[0036] In the basic circulation of the circulating water system, the control valve 11 is opened, and the return water tank 1 and the circulating water tank 2 are connected. Starting from the return water tank 1, the circulating water flows through the return water tank 1 and the circulating water tank 2 in sequence, and then the upper water pump 3 circulates the circulating water from the first upper water inlet to the equipment to be cooled, so that the equipment to be cooled is cooled and then returned to the return water tank 1 through the return water pipe 21, completing a basic circulation. During this period, when the circulating water flows through the return water pipe 21, the temperature of the circulating water is monitored in real time by the first temperature transmitter 4. According to the actual needs of the producer, if the water temperature is still displayed to adopt the basic circulation, the next basic circulation is carried out, otherwise the circulating water is controlled to enter other circulations.

[0037] In an embodiment of the present application, the above-mentioned medium and low temperature cycle includes: the above-mentioned return water pool 1, the above-mentioned circulating water pool 2, the above-mentioned second water inlet, the above-mentioned cooling tower 5, the above-mentioned circulating water pool 2, the above-mentioned first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop.

[0038] In the medium and low temperature cycle of the circulating water system, the control valve 11 is opened, the return water tank 1 and the circulating water tank 2 are connected, and the cooling tower 5 is opened. When the first temperature transmitter 4 shows that the temperature of the circulating water should adopt the medium and low temperature cycle, starting from the return water tank 1, the circulating water flows through the return water tank 1 and the circulating water tank 2 in turn, and the upper water pump 3 inputs the circulating water from the second upper water inlet into the cooling water tower 5 for cooling, and then returns to the circulating water tank 2, and then the upper water pump 3 circulates the circulating water from the first upper water inlet to the equipment to be cooled, so that the equipment to be cooled is cooled and then returned to the return water tank 1 through the return water pipe 21, completing a medium and low temperature cycle. It can be understood that while the medium and low temperature cycle is being carried out, part of the circulating water is also undergoing a basic cycle, that is, the circulating water flows through the return water tank 1 and the circulating water tank 2 in turn, and then the upper water pump 3 circulates the circulating water from the first upper water inlet to the part of the equipment to be cooled. Similarly, when the circulating water flows through the return pipe 21, the first temperature transmitter 4 monitors the temperature of the circulating water in real time. According to the actual needs of the producer, if the water temperature is still displayed to adopt medium and low temperature circulation, the next medium and low temperature circulation is carried out. Otherwise, the circulating water system is controlled to enter other circulations.

[0039] In an embodiment of the present application, a cooling tower pump 9 is connected in series between the return water tank 1 and the cooling tower 5, a jacket is provided on the refrigeration unit 6, and a refrigerator pump 10 is connected in series between the circulating water tank 2 and the jacket; the low-temperature cycle includes: the return water tank 1, the cooling tower pump 9, the cooling tower 5, the circulating water tank 2, the first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop; the return water tank 1, the cooling tower pump 9, the cooling tower 5, the circulating water tank 2, the third water inlet, the refrigeration unit 6 and the equipment to be cooled are connected in sequence to form a closed circulation loop; the circulating water tank 2, the refrigerator pump 10, the jacket and the cooling water tower 5 are connected in sequence to form a closed circulation loop.

[0040] In the low-temperature circulation of the circulating water system, the control valve 11 is closed, the cooling tower 5 is turned on, and the refrigeration unit 6 is turned on. When the first temperature transmitter 4 shows that the temperature of the circulating water should be circulated at a low temperature, it is usually when the load of the production line is large, or the ambient temperature is high and the required cooling water temperature is low. The installation of the refrigeration unit 6 can well alleviate the operating pressure of the cooling tower 5. Furthermore, the circulating water is no longer input into the cooling tower 5 through the second water inlet to reduce the operating pressure of the water pump 3. Instead, the cooling tower pump 9 is connected in series between the return water tank 1 and the cooling tower 5, and the circulating water in the return water tank 1 is input into the cooling tower 5 by the cooling tower pump 9 for the first cooling, and then the circulating water flows out of the cooling tower 5 and flows into the circulating water tank 2 for standby.

[0041] In addition, a jacket is provided on the refrigerating unit 6 for inputting circulating water after the first cooling to cool the refrigerating unit 6, so as to avoid overheating of the refrigerating unit 6 and better adapt to the working conditions. A refrigerating machine pump 10 is connected in series between the circulating water pool 2 and the jacket, and the refrigerating machine pump 10 inputs the circulating water after the first cooling in the circulating water pool 2 into the jacket from the third water inlet to cool the refrigerating unit 6. After that, the circulating water flows out of the jacket and flows into the cooling tower 5 for the second cooling, and then returns to the circulating water pool 2 for standby. Usually, the refrigerating unit 6 and its matching refrigerating machine pump 10 can automatically adjust the operating load according to the actual situation. For example, when the production line load is large or the circulating return water temperature is high, the refrigerating unit 6 can increase the operating intensity according to the feedback to adapt to the actual production needs. At the same time, the matching refrigerating machine pump 10 also increases the operating intensity accordingly to better cool the refrigerating unit 6.

[0042] Finally, the circulating water in the circulating water pool 2 is circulated from the first water inlet to the equipment to be cooled by the water pump 3, and is input from the third water inlet to the refrigeration unit 6 for freezing and cooling before being circulated to the equipment to be cooled. The two together cool the equipment to be cooled. After that, the circulating water also returns to the return water pool 1 through the return water pipe 21 to complete a low-temperature cycle. Similarly, when the circulating water flows through the return water pipe 21, the temperature of the circulating water is monitored in real time by the first temperature transmitter 4. According to the actual needs of the producer, if the water temperature is still displayed to adopt the low-temperature cycle, the next low-temperature cycle is carried out. Otherwise, the circulating water system is controlled to enter other cycles.

[0043] In an embodiment of the present application, the connecting pipe between the first water inlet and the device to be cooled is a normal temperature pipe 7 , and the connecting pipe between the refrigeration unit 6 and the device to be cooled is a low temperature pipe 8 .

[0044] It can be understood that the temperature of the circulating water in the normal temperature pipe 7 is lower than the temperature of the circulating water in the low temperature pipe 8 .

[0045] In an embodiment of the present application, a first regulating valve 12 is provided on the above-mentioned normal temperature pipe 7; a second regulating valve 13 is provided on the connecting pipe between the above-mentioned second water inlet and the above-mentioned cooling tower 5; a third regulating valve 14 is provided on the connecting pipe between the above-mentioned third water inlet and the above-mentioned refrigeration unit 6; a first flow transmitter 15 and a second flow transmitter 16 are respectively provided on the above-mentioned low-temperature pipe 8 and the above-mentioned normal temperature pipe 7, which are used for feedback adjustment of the above-mentioned first regulating valve 12, the above-mentioned second regulating valve 13 and the above-mentioned third regulating valve 14.

[0046] In addition to dividing the circulating water system into different cycles based on the temperature conditions of the PVC-O pipe production line, the circulating water system should be able to meet the water supply at the maximum production load of the workshop during engineering design according to the actual needs of the producer, such as the number of production lines in the workshop and the type of pipes produced in batches. The maximum production load corresponds to the 100% load of the circulating water system. A flow transmitter is set in the circulating water system. On the basis of ensuring the supply of circulating water when the entire workshop is operating at maximum load, according to the actual water use of the production line, including the pipe diameter of the current production batch, the number of production lines that need water at the time, etc., the flow of circulating water in the circulation loop is adjusted through real-time feedback of the flow transmitter to meet the water load under different working conditions.

[0047] When the circulating water system is in basic circulation, the circulating water flow in the normal temperature pipe 7 is monitored by the first flow transmitter 15, and the opening of the first regulating valve 12 is automatically adjusted according to the parameters set in advance by the manufacturer to control the circulating water flow in the normal temperature pipe 7; when the circulating water system includes medium and low temperature circulation, the circulating water flow in the normal temperature pipe 7 is monitored by the first flow transmitter 15, and the openings of the first regulating valve 12 and the second regulating valve 13 are automatically adjusted according to the parameters set in advance by the manufacturer to control the circulating water flow in the normal temperature pipe 7 and the circulating water flow input to the cooling tower 5; when the circulating water system is in low temperature circulation, the circulating water flow in the normal temperature pipe 7 is monitored by the first flow transmitter 15, and the opening of the first regulating valve 12 is automatically adjusted according to the parameters set in advance by the manufacturer to control the circulating water flow in the normal temperature pipe 7, and the circulating water flow in the low temperature pipe 8 is monitored by the second flow transmitter 16, and the opening of the third regulating valve 14 is automatically adjusted according to the parameters set in advance by the manufacturer to control the circulating water flow in the low temperature pipe 8.

[0048] By adjusting the openings of the first regulating valve 12, the second regulating valve 13 and the third regulating valve 14, the flow in the circulation pipeline is distributed and controlled to better adapt to various working conditions, such as the situation where a large circulating water flow rate is required when multiple production lines are producing at the same time, or the temperature of the equipment to be cooled is too high and needs to be cooled quickly.

[0049] In an embodiment of the present application, a normal temperature water regulating valve 17 and a low temperature water regulating valve 18 are respectively provided at one end of the normal temperature pipe 7 and the low temperature pipe 8 close to the equipment to be cooled; after the normal temperature pipe 7 and the low temperature pipe 8 are merged into a water inlet main pipe 19, they are connected to the equipment to be cooled, and a second temperature transmitter 20 is provided on the water inlet main pipe 19 for monitoring the circulating water temperature in the water inlet main pipe 19 and feedback-adjusting the normal temperature water regulating valve 17 and the low temperature water regulating valve 18.

[0050] After the cooling treatment of the circulating water system, the circulating water is ready to be input into the equipment to be cooled through the normal temperature pipe 7 and the low temperature pipe 8. A second temperature transmitter 20 is set on the water inlet main pipe 19 after the two pipes merge. At this time, the circulating water temperature monitored by the second temperature transmitter 20 is the circulating water temperature input into the equipment to be cooled. The monitored temperature is also affected by environmental factors. According to the actual needs of the producer, the corresponding control parameters are set in the second temperature transmitter 20 to detect the circulating water temperature in the water inlet main pipe 19 in real time. The temperature should meet the set requirements; otherwise, the second temperature transmitter 20 automatically feedbacks and adjusts the opening of the normal temperature water regulating valve 17 and the low temperature water regulating valve 18 to control the circulating water flow in the normal temperature pipe 7 and the low temperature pipe 8, so as to make the circulating water temperature in the water inlet main pipe 19 meet the set requirements.

[0051] According to the actual needs of the producer, in the current cycle, when the second temperature transmitter 20 shows that the circulating water temperature has reached the set value, the cooling tower 5 and / or the refrigerating unit 6 are shut down accordingly to achieve energy saving. That is, the first temperature transmitter 4 controls the opening of the cooling tower 5 and / or the refrigerating unit 6 in the circulating water system, and the second temperature transmitter 20 controls the closing of the cooling tower 5 and / or the refrigerating unit 6 in the circulating water system.

[0052] In an embodiment of the present application, a method for using a temperature-adjusting circulating water system for PVC-O pipes is also included, comprising the following steps:

[0053] S1: Temperature division: The first temperature transmitter 4 monitors the return water temperature of the circulating water system, and controls the flow ratio of the circulating water system entering the basic cycle, the medium and low temperature cycle and the low temperature cycle according to the temperature conditions.

[0054] In this step, according to the actual needs of the producer, the circulating water system is divided into basic circulation, medium and low temperature circulation and low temperature circulation, and according to the circulating water return temperature monitored by the first temperature transmitter 4, the circulating water system is respectively made to enter the basic circulation, medium and low temperature circulation or low temperature circulation. When the circulating water system is in the basic circulation, the cooling tower 5 and the refrigeration unit 6 should both be in the closed state; when the circulating water system needs to adopt the medium and low temperature circulation, the first temperature transmitter 4 will feedback control the cooling tower 5 to open to realize the medium and low temperature circulation, and the refrigeration unit 6 will remain closed at this time; similarly, when the circulating water system needs to adopt the low temperature circulation, the first temperature transmitter 4 will feedback control the cooling tower 5 and the refrigeration unit 6 to open at the same time to realize the low temperature circulation. When different circulations are adopted, different cooling equipment is turned on, and the first temperature transmitter 4 will feedback and control in real time, which can respond to different working conditions in a timely manner while saving energy consumption.

[0055] S2: Flow control: The flow transmitter is used to feedback and adjust the water outlet flow of the above-mentioned circulating water system.

[0056] In this step, according to the actual needs of the producer, under different production loads, a flow transmitter is used to monitor and adjust the circulating water flow in the circulation pipeline. Usually, a circulating water system is installed in a PVC-O pipe production workshop, and a workshop often has multiple PVC-O pipe production lines, that is, a circulating water system sometimes needs to supply multiple PVC-O pipe production lines. At this time, different circulating water flows are required in the circulating pipeline of the circulating water system to meet the production load of the workshop; at the same time, in addition to being affected by the number of production lines, the production load will also be affected by the pipe models produced in the batch. For example, pipes with large diameters generally require larger circulating water flows. Therefore, after dividing the circulating water system into three cycles according to the temperature conditions of the equipment to be cooled, it is often necessary to adjust the flow of the circulating water system to meet the water load under different working conditions.

[0057] S3: Production line control: According to the temperature monitored by the second temperature transmitter 20, the normal temperature water regulating valve 17 and the low temperature water regulating valve 18 are feedback-adjusted to control the flow rate of circulating water in the normal temperature pipeline 7 and the low temperature pipeline 8, respectively, until the circulating water temperature in the water inlet main pipeline 19 reaches the set value.

[0058] In this step, according to the actual needs of the producer, a second temperature transmitter 20 is set on the water inlet main pipeline 19 of the equipment to be cooled, that is, a water temperature monitoring is set at the water inlet of the equipment to be cooled to ensure that the temperature of the circulating water entering the equipment to be cooled meets the requirements of this production. When the second temperature transmitter 20 shows that the water inlet temperature does not meet the requirements, the opening of the normal temperature water regulating valve 17 and the low temperature water regulating valve 18 can be adjusted by feedback to control the flow of circulating water in the normal temperature pipeline 7 and the low temperature pipeline 8, and then accurately control the temperature of the circulating water entering the equipment to be cooled, and the control accuracy can reach ±0.1°C, which is suitable for various production situations.

[0059] The second temperature transmitter 20 cooperates with the first temperature transmitter 4, and the second temperature transmitter 20 can control the shutdown of each cooling device in the circulating water system. For example, when a medium-low temperature cycle is used in the secondary cycle, a temperature control point is set on the second temperature transmitter 20. When the second temperature transmitter 20 shows that the circulating water temperature in the water inlet main pipeline 19 reaches the cooling temperature required for the current production, the cooling tower 5 can be feedback controlled to be closed. The same applies to the low-temperature cycle.

[0060] The technical solution of the present application is further described below in conjunction with the accompanying drawings and embodiments.

[0061] Example

[0062] like Figure 1 As shown, Figure 1 This is a process flow chart of the circulating water system of this application.

[0063] This embodiment is implemented according to the technical solution in the above specific implementation. Taking the PVC-O pipe production line equipment model A, which produces pipes with a diameter of dn100 to dn280 as an example, when the circulating water system of this application is used, it is performed as follows:

[0064] According to the actual needs of the producer, the circulating water system of this workshop is designed as follows: when the temperature displayed by the first temperature transmitter 4 is ≤15℃, the basic circulation is adopted; when the temperature displayed by the first temperature transmitter 4 is greater than 15℃ and ≤25℃, the medium and low temperature circulation is adopted; when the temperature displayed by the first temperature transmitter 4 is greater than 25℃, the low temperature circulation is adopted. And the maximum load of this workshop is to open 10 PVC-O pipe production lines (model A) at the same time. The second temperature transmitter 20 in this embodiment is installed on the water inlet main pipeline 19 of the extruder main machine, and the cooling water inlet temperature required by the production equipment of this production workshop is set to 5℃.

[0065] The specific implementation status is summarized in Table 1:

[0066] Table 1 Combination of the influence of load and ambient temperature in the embodiment

[0067]

[0068] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present application.

Claims

1. A temperature regulating circulating water system for PVC-O pipes, comprising: A circulating water pool (2), a cooling tower (5), a refrigerating unit (6) and a water supply pump (3), characterized in that the circulating water system includes a basic circulation and a cooling circulation, the upstream of the circulating water pool (2) is connected to a return water pool (1), a control valve (11) is provided on the connecting pipe between the return water pool (1) and the circulating water pool (2), the connecting pipe between the equipment to be cooled and the return water pool (1) is a return water pipe (21), and a first temperature transmitter (4) is provided on the return water pipe (21) for feedback control of the flow rate ratio of the circulating water entering the basic circulation and the cooling circulation; The water supply pump (3) is provided with three parallel water outlets, namely the first water supply outlet, the second water supply outlet and the third water supply outlet; the basic cycle comprises: the return water pool (1), the circulating water pool (2), the first water supply outlet and the equipment to be cooled are connected in sequence to form a closed circulation loop; the cooling cycle comprises: a medium and low temperature cycle and a low temperature cycle, the medium and low temperature cycle comprises: circulating water flows through the second water supply outlet, and the circulating water is cooled by the cooling tower (5); the low temperature cycle comprises: circulating water flows through the third water supply outlet, and the circulating water is cooled by the refrigeration unit (6).

2. A temperature regulating circulating water system for PVC-O pipes according to claim 1, characterized in that: The medium and low temperature cycle comprises: the return water pool (1), the circulating water pool (2), the second water inlet, the cooling tower (5), the circulating water pool (2), the first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop.

3. A temperature regulating circulating water system for PVC-O pipes according to claim 1, characterized in that: A cooling tower pump (9) is connected in series between the return water tank (1) and the cooling tower (5), a jacket is provided on the refrigerating unit (6), and a refrigerator pump (10) is connected in series between the circulating water tank (2) and the jacket; the low-temperature cycle comprises: the return water tank (1), the cooling tower pump (9), the cooling tower (5), the circulating water tank (2), the first water inlet and the equipment to be cooled are connected in sequence to form a closed circulation loop; the return water tank (1), the cooling tower pump (9), the cooling tower (5), the circulating water tank (2), the third water inlet, the refrigerating unit (6) and the equipment to be cooled are connected in sequence to form a closed circulation loop; the circulating water tank (2), the refrigerator pump (10), the jacket and the cooling tower (5) are connected in sequence to form a closed circulation loop.

4. A temperature regulating circulating water system for PVC-O pipes according to any one of claims 1 to 3, characterized in that: The connecting pipe between the first water inlet and the equipment to be cooled is a normal temperature pipe (7), and the connecting pipe between the refrigeration unit (6) and the equipment to be cooled is a low temperature pipe (8).

5. A temperature regulating circulating water system for PVC-O pipes according to claim 4, characterized in that: The normal temperature pipeline (7) is provided with a first regulating valve (12); the connecting pipeline between the second water inlet and the cooling tower (5) is provided with a second regulating valve (13); the connecting pipeline between the third water inlet and the refrigeration unit (6) is provided with a third regulating valve (14); the low temperature pipeline (8) and the normal temperature pipeline (7) are respectively provided with a first flow transmitter (15) and a second flow transmitter (16) for feedback regulation of the first regulating valve (12), the second regulating valve (13) and the third regulating valve (14).

6. A temperature regulating circulating water system for PVC-O pipes according to claim 5, characterized in that: A normal temperature water regulating valve (17) and a low temperature water regulating valve (18) are respectively provided at one end of the normal temperature pipe (7) and the low temperature pipe (8) close to the equipment to be cooled; after the normal temperature pipe (7) and the low temperature pipe (8) are merged into a water inlet main pipe (19), they are connected to the equipment to be cooled, and a second temperature transmitter (20) is provided on the water inlet main pipe (19) for monitoring the temperature of the circulating water in the water inlet main pipe (19) and feedback-adjusting the normal temperature water regulating valve (17) and the low temperature water regulating valve (18).

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