Circulating loop confluence and pipe combining system among multiple buildings in a park and its control method

Abstract

An embodiment of the present invention discloses a system for confluence and parallel piping of a circulating loop between multiple buildings in a park and a control method thereof. The system includes a pipe network control unit and a common return pipe. Each building in the park is provided with a circulating partition, and the return water pipes of the circulating partitions are all connected to the common return pipe. A return water valve and a pressure gauge are arranged on the return water pipes of the circulating partitions before connecting to the common return pipe. The present invention avoids difficult hydraulic calculations and head loss estimations, but realizes an ideal flow balance result by monitoring and adjusting the actual process. The method is simple and efficient, has high engineering application value, and also shows good effectiveness and feasibility through engineering practice. The application of the present invention can also enhance the engineering feasibility and scheme flexibility of building a direct drinking water system for pipelines in a large office building park.

Description

Technical Field

[0001] The present invention relates to the technical field of piped drinking water, and in particular to a circulation loop converging and pipe-joining system between multiple buildings in a park and a control method thereof. Background Art

[0002] When multiple circulation zones between buildings converge and share return pipes, meeting flow balance requirements requires careful consideration of zone design and the addition of pressure reducing or regulating valves. However, current engineering practices lack quantifiable regulation methods and effective monitoring capabilities. This is especially true for complex scenarios like large office buildings, where the total head loss in each zone must be considered, posing a significant challenge to design and commissioning.

[0003] In a multi-circulation zone system, a return water confluence and pipe layout is often used. In terms of design, two situations are generally considered:

[0004] ① The return water from the zones with similar head shall be combined into one pipe. Figure 1 .

[0005] ② After the high-lift zone return water is reduced in pressure, it will be combined with the low-lift zone return water and piped together. Figure 2 .

[0006] 1. Defects and shortcomings of merging return water from zones with similar head:

[0007] 1. The buildings in a large office park are quite different from each other. It is impossible to achieve completely consistent lifts for each building based on its specific vertical zoning.

[0008] 2. The layout of drinking water points varies significantly across buildings, resulting in different numbers of risers in each zone. Furthermore, the piping construction plans for each building may differ, and actual on-site construction may differ from design calculations, resulting in different total head losses in each zone.

[0009] The above will lead to hydraulic imbalance and flow imbalance in each circuit between buildings.

[0010] 2. After the high-lift partition return water is decompressed, it is merged with the low-lift partition return water and piped together - defects and shortcomings:

[0011] As a pressure-stabilizing device with adjustable output pressure, a pressure reducing valve can easily eliminate head differences and achieve static pressure balance. During circulation, the pressure head before the pipes undergoes dynamic changes due to flow changes and redistribution within each circuit. The pressure reducing valve counteracts this change. Furthermore, the pressure reducing valve can only stabilize output pressure but cannot eliminate differences in total head loss, thus failing to achieve the precise, quantifiable flow balance. Therefore, other more effective regulation and monitoring methods must be used in conjunction with the valve.

[0012] As Figure 3 , an office building park is generally composed of multiple buildings, with different heights and different numbers of risers for each building. During design, the water supply network for each building is reasonably vertically partitioned. The vertical partition also determines the division of the circulation partition.

[0013] The design of the circulation structure is generally as follows:

[0014] 1. Each circulation partition between buildings is independent. Then each loop returns water completely independently, and the system operates smoothly. However, the pipeline length is relatively long, the engineering quantity is large, and the cost is also high.

[0015] 2. For partitions with similar head between buildings, the way of combining and merging the return water pipes can be adopted. Such as Figure 3 "Circulation Partition 1", "Circulation Partition 2" and "Circulation Partition 3" in

[0016] After the pipes are combined, the return water same - path layout is still adopted, and the return water same - path pipes are increased.

[0017] This way saves pipe materials and cost, but there may be a risk of flow imbalance in each loop between buildings because:

[0018] (1) There are differences in head;

[0019] (2) The number of parallel risers is different, and there are differences in head loss;

[0020] (3) During the actual construction of each building, the pipeline laying paths, the number of elbows and joints are different, and there are differences in head loss.

[0021] It is outlined in "Technical Specification for Building and Community Piped Direct Drinking Water System (CJJ T 110 - 2017)" that pressure reducing valves are used for large head differences; flow balance valves are suitable for each loop during the combination of return water pipes. However, no specific engineering implementation methods are given. Currently, the reality is that flow balance valves are difficult to debug, troublesome to maintain, costly, and there is a lack of food - grade small - diameter products suitable for the piped direct drinking water system in the market. Using pressure reducing valves is the most common and convenient way. No matter which way, there is a lack of quantitative debugging methods and monitoring means, and the effect is difficult to evaluate. Summary of the Invention

[0022] The technical problem to be solved by the embodiments of the present invention is to provide a system for combining and merging the circulation loops between multiple buildings in a park and its control method to achieve the flow balance adjustment of the combined and merged circulation loops between multiple buildings in an office building park.

[0023] To solve the above technical problems, an embodiment of the present invention provides a confluence and parallel pipe system for a circulating loop between multiple buildings in a park, including a pipe network control unit and a return water common pipe. Each building in the park is provided with a circulating partition, and the return water pipes of the circulating partitions are all connected to the return water common pipe. A return water valve and a pressure gauge are arranged on the return water pipes of the circulating partitions before connecting to the return water common pipe.

[0024] Before circulation, the pipe network control unit records the return water pressure data detected by the pressure gauges of each circulating partition; after starting the circulation, it records the return water pressure data of each circulating partition.

[0025] Then, calculate the difference between the two pressure data before and after circulation for each circulating partition, determine the building corresponding to the circulating partition with the smallest difference as the most unfavorable building, and mark this difference as P0.

[0026] Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings so that the pressure differences before and after circulation of each circulating partition are the same as P0, realizing the flow balance of confluence and parallel pipes.

[0027] Further, after starting the circulation, compare the circulating partitions of each building, and take the building with the highest head and the most water supply risers as the most favorable building, and pre-adjust its return water valve to reduce the opening of the return water valve.

[0028] Further, after the adjustment is completed, if the difference data P0 of the most unfavorable building changes, then fine-tune the return water valves of other buildings again so that the pressure differences before and after circulation of the circulating partitions of other buildings are dynamically the same as P0.

[0029] Correspondingly, an embodiment of the present invention also provides a control method for a confluence and parallel pipe system for a circulating loop between multiple buildings in a park, including:

[0030] Recording step: Before circulation, record the return water pressure data of each circulating partition; after starting the circulation, record the return water pressure data of each circulating partition.

[0031] Calculation step: Calculate the difference between the two pressure data before and after circulation for each circulating partition, determine the building corresponding to the circulating partition with the smallest difference as the most unfavorable building, and mark this difference as P0.

[0032] Adjustment step: Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings so that the pressure differences before and after circulation of each circulating partition are the same as P0, realizing the flow balance of confluence and parallel pipes.

[0033] Further, before the recording step, it further includes:

[0034] Preliminary adjustment step: Compare the circulating zones of each building, and select the building with the highest head and the most water supply risers as the most favorable building. After starting the circulation, pre-adjust the return water valve of this building to reduce the opening degree of the return water valve.

[0035] Furthermore, after the adjustment step, the following steps are also included:

[0036] Secondary adjustment step: After the adjustment is completed, if the difference data P0 of the most unfavorable building changes, then fine-tune the return water valves of other buildings again to make the pressure difference before and after the circulation of the circulating zones of other buildings dynamically consistent with P0.

[0037] The beneficial effects of the present invention are as follows: In view of the hydraulic differences (head differences, riser number differences, total head loss differences, etc.) existing in the circulating zones of multiple buildings in the complex scenario of a large office building park, the present invention provides an effective adjustment method for balancing flow rates and an effect monitoring means. The present invention avoids difficult hydraulic calculations and head loss estimations, but realizes the ideal flow balance result by monitoring and adjusting the actual process. The method is simple and efficient, has high engineering application value, and also shows good effectiveness and feasibility through engineering practice. The application of the present invention can also enhance the engineering feasibility and scheme flexibility of building a pipeline direct drinking water system in a large office building park. Brief Description of the Drawings

[0038] Figure 1 is a schematic structural diagram of the return water confluence and pipe connection of circulating zones with similar heads in the prior art.

[0039] Figure 2 is a schematic structural diagram of the return water confluence and pipe connection of the high-head circulating zone after pressure reduction and the return water of the low-head circulating zone in the prior art.

[0040] Figure 3 is a schematic structural diagram of the water supply pipe network of an office building park in the prior art.

[0041] Figure 4 is a schematic structural diagram of the confluence and pipe connection system of the circulating circuits between multiple buildings in the park in an embodiment of the present invention.

[0042] Figure 5 is an approximate dynamic curve of p1-p2 and Q2 of one of the circulating zones in Embodiment 1 of the present invention.

[0043] Figure 6 is a schematic structural diagram of the confluence and pipe connection system of the circulating circuits between multiple buildings in the park in Embodiment 1 of the present invention.

[0044] Figure 7 is a schematic diagram of the dynamic curve of p1-p2 and Q2 of one of the circulating zones in Embodiment 1 of the present invention.

[0045] Figure 8 It is a diagram for recording the engineering data of each circulation zone before adjustment in Embodiment 1 of the present invention.

[0046] Figure 9 It is a diagram for recording the engineering data of each circulation zone after adjustment in Embodiment 1 of the present invention.

[0047] Figure 10 It is a schematic flow chart of the control method for the circulation loop confluence and parallel pipe system between multiple buildings in the park in the embodiment of the present invention.

[0048] Explanation of the reference numerals in the drawings

[0049] Building 1, Circulation zone 2, Return water pipe 3, Return water equalization pipe 4, Water supply riser 5, Return water valve 6, Return water common pipe 7, Pressure gauge 8. Embodiment

[0050] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0051] In the embodiments of the present invention, if there are directional indicators (such as up, down, left, right, front, back...), they are only used to explain the relative positional relationship and movement conditions between components in a certain specific posture (as shown in the drawings). If the specific posture changes, the directional indicators will also change accordingly.

[0052] In addition, in the present invention, the descriptions such as "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0053] Please refer to Figure 4 and Figure 6 , the circulation loop confluence and parallel pipe system between multiple buildings in the park in the embodiment of the present invention includes a pipe network control unit and a return water common pipe. Each building in the park is provided with a circulation zone, the return water pipes of the circulation zones are all connected to the return water common pipe, and a return water valve and a pressure gauge are arranged on the return water pipes of the circulation zones before connecting to the return water common pipe.

[0054] Before circulation, the pipe network control unit records the return water pressure data detected by the pressure gauges in each circulation zone, which are respectively denoted as p 11 , p 21 , p 31 , …… p n1 ; after starting the circulation, it records the return water pressure data in each circulation zone; which are respectively denoted as p 12 , p 22, p 32 , ……p n2 ; n is the number of buildings. The subscript of the pressure value before the cycle is 1, and the subscript of the pressure value after the cycle is 2.

[0055] Then calculate the difference between the pressure data before and after the two cycles of each circulation zone, and determine the building corresponding to the circulation zone with the smallest difference as the most unfavorable building, and mark this difference as P0;

[0056] Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings to make p 12 , p 22 , p 32 , ……p n2 be respectively consistent with the differences between p 11 , p 21 , p 31 , ……p n1 and P0, and achieve the flow balance of the confluence and pipe connection.

[0057] As an implementation method, after starting the cycle, compare the circulation zones of each building, and take the building with the highest head and many risers as the most favorable building, and pre-adjust its return water valve to reduce the opening of the return water valve. The larger the number of risers, the smaller the equivalent impedance of the circulation zone. Therefore, the number of risers is one of the factors affecting the judgment of the favorable building.

[0058] As an implementation method, after the adjustment is completed, if the difference data P0 of the most unfavorable building changes, then fine-tune the return water valves of other buildings again to make the pressure difference before and after the circulation of other buildings' circulation zones dynamically consistent with P0.

[0059] Please refer to Figure 10 , the control method of the confluence and pipe connection system for the circulation loop between multiple buildings in the park of the present invention includes:

[0060] Recording step: Before the cycle, record the return water pressure data of each circulation zone; after starting the cycle, record the return water pressure data of each circulation zone;

[0061] Calculation step: Calculate the difference between the pressure data before and after the two cycles of each circulation zone, and determine the building corresponding to the circulation zone with the smallest difference as the most unfavorable building, and mark this difference as P0;

[0062] Adjustment step: Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings to make the pressure difference before and after the circulation of each circulation zone consistent with P0, and achieve the flow balance of the confluence and pipe connection.

[0063] As an implementation method, before the recording step, it further includes:

[0064] Pre-adjustment steps: Compare the circulation zones of each building, and select the building with the highest head and more water supply risers as the most favorable building. After starting the circulation, pre-adjust its return valve to reduce the opening of the return valve.

[0065] As an embodiment, the adjusting step further includes:

[0066] Secondary adjustment steps: After the adjustment is completed, if the difference data P0 of the most unfavorable building changes, the return valves of other buildings will be fine-tuned again to make the pressure difference of the circulation partitions of other buildings before and after the circulation dynamically consistent with P0.

[0067] The present invention provides a practical and convenient method and idea for the flow balance adjustment and monitoring of the circulation loop confluence and pipe connection between multiple buildings in an office park, and has high value in engineering practice applications.

[0068] like Figure 4 This is the return water confluence and pipe connection for a circulation zone in one of the buildings in the park. Valves and pressure gauges are installed on the zone return pipes before the confluence.

[0069] Based on hydraulic analysis methods, the pipe section where the pressure gauge is located is selected as the flow section and labeled as section (z, p, V). z is the section location, p is the section pressure, and v is the section flow velocity.

[0070] According to Bernoulli's energy equation, we have:

[0071] z+p / ρg + V 2 / 2g = C (1)

[0072] z is the position head, p / ρg is the pressure head, V 2 / 2g is the flow rate head.

[0073] The physical meaning is: the total energy (mechanical energy) of the fluid flowing through the flow section is a constant.

[0074] Among them, C is a constant; z1 is the position head, which is a fixed value.

[0075] When the waterway is stationary, the energy equation of the cross section is:

[0076] z1+p1 / ρg + V1 2 / 2g = C (2)

[0077] In the cyclic state, the energy equation of the cross section is:

[0078] z2+p2 / ρg + V2 2 / 2g = C ， (3)

[0079] Since the inlet of the water supply zone basically maintains a constant pressure:

[0080] (1) There is no pressure reducing valve in the high zone, and the water pump supplies water with constant pressure and variable frequency. The pressure at the inlet of the zone remains unchanged;

[0081] (2) For the zones with vertical pressure reduction, the pressure after the pressure reducing valve basically remains unchanged.

[0082] Above, in the case of no obvious change in the external energy input, it can be approximately considered in engineering that C = C’, that is: the total energy of the fluid flowing through the cross-section is approximately unchanged.

[0083] Then: z1 + p1 / ρg + V1 2 / 2g = z2 + p2 / ρg + V2 2 / 2g (4)

[0084] Since: at the same cross-section, so: the position head z1 = z2; in the static state: V1 = 0, so there is:

[0085] p1 / ρg = p2 / ρg + V2 2 / 2g (5)

[0086] p1 - p2 = (ρ / 2) V2 2 (6)

[0087] ρ / 2 is a constant, denoted as k, then:

[0088] p1 - p2 = k V2 2 (7)

[0089] Above, its physical meaning is:

[0090] (1) When the waterway is static, V1 is 0 and p1 obtains the maximum value. That is: in the static state, the velocity head is all converted into the pressure head.

[0091] (2) When circulating, part of the pressure head p2 / ρg is converted into the velocity head V2 2 / 2g, and: the velocity increases and the pressure drops.

[0092] Converted into engineering significance:

[0093] (1) The diameters of the return water pipes of each path are equal, and the balance of the flow rate is converted into the balance of the analysis of the flow velocity.

[0094] (2) The decrease amplitude of the pressure head before and after circulation is approximately linearly related to the square of the flow velocity.

[0095] The pressure head is directly reflected in the reading of the pressure gauge (the normal stress value of the cross-sectional fluid pressure). The pressure difference before and after circulation is adjusted through the valve control for each loop between buildings, so as to achieve a basic balance of the flow rates of each circulation loop.

[0096] The approximate quantitative analysis results in engineering are as Figure 5 shown, which is the approximate dynamic curve of p1-p2 and Q2 (circulation flow rate) for a specific circulation partition of a certain project:

[0097] Figure 5 In it, the flow rate is related to the pipe diameter. For different systems, due to different designed pipe diameters, the ordinate values of the curves are different.

[0098] Example 1: As Figure 6 , the return water of the three circulation partitions between three buildings converges and is piped together. The return water pressure gauges are P a , P b , P c . The subscript of the pressure value before circulation is 1, and the subscript of the pressure value after circulation is 2. Then the parameter markings of the pressure gauges are: P a (p a1 , p a2 ), P b (p b1 , p b2 ), P c (p c1 , p c2 ).

[0099] 1. Select the most unfavorable building loop. As loop A in the figure: the head is the lowest and the number of risers is less. The most unfavorable building loop and the most unfavorable building are actually the same.

[0100] 2. Select the most favorable building loop. As loop B in the figure: the head is the highest and the number of risers is more. The flow velocity of the most favorable loop is the largest, and pre-adjust the valve to reduce the valve opening. The purpose of this step is to accelerate the speed of dynamic adjustment.

[0101] 3. Before circulation, record the return water pressure gauge data of each building, denoted as p a1 , p b1 , p c1 .

[0102] 4. Start the circulation and record the return water pressure gauge data of each building, denoted as p a2 , p b2 , p c2 .

[0103] 5. Calculate the difference between the two pressure gauge data of each building, and the building with the smallest difference is determined as the most unfavorable building, denoted as P0.

[0104] 6. Taking the data of the most unfavorable building P0 as the benchmark, adjust the return water valves p of each building a2 , p b2 , p c2 , so that the difference between it and p a1 , p b1 , p c1 is consistent with P0.

[0105] 7. The process of adjustment is also the process of redistributing the flow of each building loop, and P0 will also change. It is necessary to fine-tune p a2 , p b2 , p c2 of other loops again to make it approach P0 dynamically.

[0106] 8. The number of loops for the return water confluence and pipe connection between the buildings in the office building park generally does not exceed 4. According to engineering practice, the debugging process of dynamic approximation is relatively easy to achieve.

[0107] The quantification process of adjustment and effect monitoring in engineering is as Figure 7 shown.

[0108] Figure 7 , which is the dynamic curve of p1 - p2 and Q2 (circulation flow) in the multi-step adjustment process of a certain circulation partition. This figure also reflects the changing trend of the gradually increasing reference value P0 of the most unfavorable partition, as well as the situation of other partitions tracking and approaching it.

[0109] After the foregoing steps, the dynamic approximation of each circulation loop between the buildings is adjusted to achieve flow balance.

[0110] Its dynamic quantification process is as follows:

[0111] L represents the loop of each circulation partition of multiple buildings, where L0 is the most unfavorable building partition, that is, the reference value.

[0112] Figure 8 , which is the engineering data record of each circulation partition before adjustment.

[0113] Figure 9 , the engineering data record of each circulation partition after adjustment.

[0114] From Figures 8 to 9 , it describes the dynamic quantification process of the point coordinates of each building loop from divergence to convergence, that is, the process of flow balance between each loop between the buildings.

[0115] After the vertical zoning design of each building in the office building park, considering the project quantity and project cost, it is necessary to combine multiple return pipes between different buildings. There are significant differences among the buildings in a large office building park, such as the lift, the layout of drinking water points (the number of parallel risers), and the pipeline construction plan, etc., resulting in differences in the position head and total head loss of each circulation zone, and it is very difficult to conduct complex hydraulic calculations for each zone.

[0116] Without effective corrective measures and monitoring means, it will inevitably cause hydraulic imbalance and flow imbalance between the circulation zones of each building.

[0117] In view of the hydraulic differences (lift height difference, difference in the number of risers, difference in total head loss, etc.) existing in each circulation zone among multiple buildings in the complex scenario of a large office building park, the present invention provides an effective adjustment method for balancing flow and a means for monitoring the effect. This technology avoids difficult hydraulic calculations and head loss estimation, but realizes the ideal flow balance result by monitoring and adjusting the actual process. The method is simple and efficient, has high engineering application value, and also shows good effectiveness and feasibility through engineering practice. At the same time, this patent avoids using complex and expensive devices (such as flow regulating valves) and over-flow meters (flow meters) that are troublesome to install and maintain and have an impact on water quality, which is convenient for engineering implementation. The application of the technology of the present invention can also enhance the engineering feasibility and scheme flexibility of building a pipeline direct drinking water system in a large office building park.

[0118] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principle and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalent scope.

Claims

1. A confluence and pipe combination system for a circular loop between multiple buildings in a park, comprising a pipe network control unit and a common return pipe. Each building in the park is provided with a circulation zone, and the return water pipes of the circulation zones are all connected to the common return pipe. It is characterized in that, Before the return water pipe of the circulating partition is connected to the common return water pipe, a return water valve and a pressure gauge are provided. Before the circulation, the pipe network control unit records the return water pressure data detected by the pressure gauges of each circulating partition; after the circulation is started, it records the return water pressure data of each circulating partition. Then, calculate the difference between the two pressure data before and after the circulation of each circulating partition, determine the building corresponding to the circulating partition with the smallest difference as the most unfavorable building, and mark this difference as P0. Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings so that the pressure differences before and after the circulation of each circulating partition are the same as P0, realizing the flow balance of the confluence and parallel pipes. After the circulation is started, compare the circulating partitions of each building, and take the building with the highest head and the most water supply risers as the most favorable building, and pre-adjust its return water valve to reduce the opening of the return water valve. After the adjustment is completed, if the difference data P0 of the most unfavorable building changes, then fine-tune the return water valves of other buildings again so that the pressure differences before and after the circulation of the circulating partitions of other buildings are dynamically the same as P0.

2. A control method for a circulating loop confluence and parallel pipe system between multiple buildings in a park as described in claim 1, characterized in that, Including: Recording step: Before the circulation, record the return water pressure data of each circulating partition. After the circulation is started, record the return water pressure data of each circulating partition. Calculation step: Calculate the difference between the two pressure data before and after the circulation of each circulating partition, determine the building corresponding to the circulating partition with the smallest difference as the most unfavorable building, and mark this difference as P0. Adjustment step: Based on the difference data P0 of the most unfavorable building, adjust the return water valves of other buildings so that the pressure differences before and after the circulation of each circulating partition are the same as P0, realizing the flow balance of the confluence and parallel pipes.

3. The control method of the circulating loop confluence and pipe combination system between multiple buildings in the park according to claim 2, characterized in that, Before the recording step, it also includes: Pre-adjustment step: Compare the circulating partitions of each building, and take the building with the highest head and the most water supply risers as the most favorable building. After the circulation is started, pre-adjust its return water valve to reduce the opening of the return water valve.

4. The control method of the circulating loop confluence and parallel pipe system between multiple buildings in the park according to claim 2, characterized in that, After the adjustment step, it also includes: Secondary adjustment step: After the adjustment is completed, if the difference data P0 of the most unfavorable building changes, then fine-tune the return water valves of other buildings again so that the pressure differences before and after the circulation of the circulating partitions of other buildings are dynamically the same as P0.

Images