JP5005304B2 - Drainage measurement method for advanced stand-by vertical pump - Google Patents

Description

  The present invention relates to a method for measuring the amount of drainage of a prior standby vertical shaft pump.

  In recent years, the underground penetration rate of rainwater has decreased due to urbanization and road paving. In addition, the occurrence of localized torrential rain due to the heat island phenomenon is increasing. Due to these causes, a large amount of rainwater tends to flow into the sewer drain pumping station in a short time. In order to cope with this short time and large amount of rainwater inflow, the pump is started in advance based on rainfall information, etc., and drainage starts at the same time as rainwater flows into the drainage pump station, and the water level in the water absorption tank There is an increasing demand for a stand-by-stand vertical pump that can maintain the operating state even if the air pressure fluctuates.

  A vertical shaft pump that realizes a preliminary standby operation by introducing air into a casing below the impeller is known (Patent Document 1). This type of stand-by type vertical shaft pump operates even when the water level in the water absorption tank is lower than the drain water level above the impeller in the casing, so the water level in the water absorption tank is above the drain water level and air is mixed in. In addition to the operation state in which water is drained (normal drainage operation state), the operation state in which water is drained in a state where air is mixed (air-water mixing operation), and the impeller is formed with an air pool below the impeller There is an operation state (air lock operation) in which a water column is formed above.

  From the viewpoint of reducing energy consumption, improving the management level, etc., there is an increasing demand for highly accurate measurement of the amount of drainage of the stand-by type vertical shaft pump. However, if the amount of water discharged in the air / water mixing operation is calculated from the actual head (measured value), the characteristic curve indicating the relationship between the amount of water discharged and the total head, and the pipe resistance, the amount of water discharged is overestimated. Become. On the contrary, if the amount of water discharged in the air-water mixing operation is zero, the amount of water discharged will be underestimated. Therefore, none of these methods is accurate. Patent Document 2 describes a method for measuring the amount of drainage of a prior standby vertical shaft pump including air-water mixing operation. However, in the measurement method described in Patent Document 2, it is necessary to execute complicated calculations.

JP 2004-162644 A JP-A-6-26899

  This invention makes it a subject to measure the amount of drainage of a prior | preceding standby type | formula vertical shaft pump including an air-water mixing operation state simply and with high precision.

The first aspect of the present invention is a method for measuring the amount of drainage in which a prior standby vertical shaft pump having an air supply port at a position closer to the suction port than the impeller of the casing drains the water in the water absorption tank to the discharge water tank. The water absorption level that is the water level of the water absorption tank is measured by the first water level sensor, the discharge water level that is the water level of the discharge water tank is measured by the second water level sensor, and is measured by the first water level sensor. If the water absorption level is at a position closer to the suction port than the front edge of the impeller and exceeds an upper threshold value that is a water level corresponding to the air supply port, the water level measured by the first water level sensor The discharge amount is calculated based on the water absorption level, the discharge water level measured by the second water level sensor, the relationship between the total head and the drainage amount in the normal drainage operation state measured in advance, and the pipe resistance measured in advance. And measured by the first water level sensor. If the water absorption level is equal to or lower than the upper threshold value and exceeds a lower threshold value that is a predetermined water level above the water level of the suction port, the relationship between the water absorption level and the drainage amount measured in advance is used. The amount of drainage is calculated, and if the water absorption level measured by the first water level sensor is equal to or lower than the lower threshold, the drainage amount measurement method for a prior standby vertical shaft pump is provided.

The second aspect of the present invention is a method of measuring the amount of drainage by which a prior standby vertical shaft pump having an air supply port at a position closer to the suction port than the impeller of the casing drains the water in the water absorption tank to the discharge water tank. The water absorption level that is the water level of the water absorption tank is measured by the first water level sensor, the discharge water level that is the water level of the discharge water tank is measured by the second water level sensor, and is measured by the first water level sensor. If the water absorption level is at a position closer to the suction port than the front edge of the impeller and exceeds an upper threshold value that is a water level corresponding to the air supply port, the water level measured by the first water level sensor The discharge amount is calculated based on the water absorption level, the discharge water level measured by the second water level sensor, the relationship between the total head and the drainage amount in the normal drainage operation state measured in advance, and the pipe resistance measured in advance. And measured by the first water level sensor. If the water absorption level is not more than the upper threshold value and exceeds a lower threshold value that is a predetermined water level above the water level of the suction port, the discharge amount is set as a predetermined specified drainage amount, If the water absorption level measured by one water level sensor is less than or equal to the lower threshold value, a method for measuring the amount of drainage of a stand-by type vertical shaft pump is provided in which the amount of drainage is zero.

  By the method for measuring the amount of waste water of the present invention, the amount of waste water of the preceding standby vertical shaft pump including the air-water mixing operation state can be measured easily and with high accuracy.

  Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
Referring to FIG. 1, a prior standby vertical shaft pump (hereinafter simply referred to as a vertical pump) 1 drains water, such as rainwater, flowing into a water absorption tank 2 of a drainage pump station from an inflow side pipe (not shown) into a discharge water tank 3. To do. The vertical shaft pump 1 includes a casing 5 extending in the vertical direction, and a rotating shaft 6 extending in the vertical direction is disposed in the casing 5. An impeller 7 is fixed to the lower end of the rotating shaft 6. The upper end of the rotating shaft 6 protrudes outside the casing 5 and is connected to a motor 8 schematically shown. One end of a discharge-side pipe 9 is connected to the upper end (discharge side) of the casing 5. The other end of the pipe 9 is open in the discharge water tank 3. An air supply port 10a which is one end of the air introduction pipe 10 is opened in the casing 5 below the impeller 7 (on the suction port 5a side). The other end of the air introduction pipe 10 is open to the atmosphere.

  A first water level sensor 11 is arranged in the water absorption tank 2. In the present embodiment, the water level (water absorption level TP) in the water absorption tank 2 measured by the first water level sensor 11 is a distance measured downward from a reference height set above the water absorption tank 2 (downward). In order to show that, the sign of the water absorption level TP is minus.) Similarly, a second water level sensor that measures the water level (discharge water level TE) in the discharge water tank 3 is disposed in the discharge water tank 3. The water absorption level TP measured by the first water level sensor 11 and the discharge water level TE measured by the first water level sensor 12 are always input to the arithmetic unit 15. The actual head height hd is obtained from the water absorption level TP and the discharge water level TE (hd = TE-TP).

The vertical pump 1 has approximately three operating states. First, when the water absorption level TP is sufficiently high, for example, when the water absorption level TP is higher than the water level TP ₁ corresponding to the upper end of the impeller 7, there is a normal drainage operation state in which water is drained without air being mixed therein. In addition, there is an air-water operation state in which water is drained in a state where air generated as the water absorption level TP decreases is mixed. Further, there is an air lock operation state in which an air pool is formed below the impeller 7 and a water column is formed above the impeller 7, which is generated by further lowering the water absorption level TP from the air-water operation state.

  The arithmetic device 15 includes a storage unit 16 and a processing unit 17.

The storage unit 16 stores in advance at least the following information and a method or procedure for calculating the drainage amount Q of the vertical shaft pump 1 based on the following information.
1) Relationship between total head H and drainage amount Q when the vertical shaft pump 1 is in a normal drainage operation state (HQ characteristics).
2) Pipe line resistance from the suction port of the vertical shaft pump 1 to the outlet of the pipe 9.
3) Relational expression for calculating the amount Q of drainage from the actual head hd, HQ characteristics, and pipe resistance. This relation is well known to those skilled in the art.
4) Upper threshold value TP _UP which is the water level corresponding to the air supply port.
5) A lower threshold value TP _LW lower than the upper threshold value TP _{UP and} higher than the water level TP ₀ of the suction port 5a. This lower threshold value TP _LW corresponds to the water absorption level TP at which the vertical pump 1 shifts to the air lock operation when the water level further decreases. More specifically, the lower threshold value TP _LW is determined by the loss of air flowing into the casing 5 from the suction port 5a at the lower end of the casing 5 and the air supply port 10a through the air introduction pipe 10 into the casing 5. It corresponds to the water absorption level TP that balances the loss of inflowing air.
6) Relationship between the water absorption level TP and the drainage amount Q of the vertical pump 1 when the water absorption level TP is equal to or lower than the upper threshold value TP _UP and higher than the lower threshold value TP _LW (see FIG. 3). In this case, the amount of drainage Q decreases as the water absorption level TP decreases.

  The processing unit 17 calculates the drainage amount Q of the vertical pump 1 based on the water absorption level TP and the discharge water level TE input from the water level sensors 11 and 12 and the information and procedure stored in the storage unit 16, and calculates the calculated drainage amount Q. It is displayed on the display device 18. Specifically, the processing unit 17 calculates the drainage amount Q of the vertical shaft pump 1 as follows.

When the water absorption level TP is higher than the upper threshold value TP _UP (TP _UP <TP), the drainage amount Q of the vertical pump 1 is calculated based on the information 1) to 3) described above. Specifically, the actual head hd of the vertical pump 1 is obtained from the water absorption level TP and the discharge water level TE input from the water level sensors 11 and 12. Moreover, the amount Q of drainage is calculated from the calculated actual head height hd, HQ characteristics, and pipe resistance. The case where the water absorption level TP is higher than the upper threshold value TP _UP (TP _UP <TP) corresponds to the case where the vertical shaft pump 1 is in the normal drain operation state.

When the water absorption level TP is equal to or lower than the upper threshold value TP _UP and higher than the lower threshold value TP _LW (TP _UP ≧ TP> TP _LW ), the water absorption level TP is determined from the water absorption level TP using the relationship of FIG. Calculate the amount of drainage Q. When the water absorption level TP is equal to or lower than the upper threshold value TP _UP and higher than the lower threshold value TP _LW (TP _UP ≧ TP> TP _LW ), the vertical pump 1 is in the air-water mixing operation state. This corresponds to the state where the amount of drainage is reduced.

When the water absorption level TP is equal to or lower than the lower threshold value TPLW (TP _LW ≧ TP), this corresponds to the case where the vertical pump 1 is in the air lock operation or the air operation, and the drainage amount Q of the vertical pump 1 Is set to zero (Q = 0).

  Table 1 below collectively shows a method for calculating the drainage amount Q of the vertical shaft pump 1 executed by the processing unit 17.

The relationship between the _HQ characteristic, the upper threshold value TP _UP , the lower threshold value TP _LW , and the water absorption level TP and the water absorption amount Q shown in FIG. It is obtained by measuring the amount of drainage Q, the water absorption level TP, and the discharge water level TE at that time.

Hereinafter, an example of a method for determining the relationship between the water absorption level TP and the drainage amount Q when the water absorption level TP is in the range of TP _UP ≧ TP> TP _LW will be described. First of all, the six types of flow rates that maximize the rated drainage (300 m ³ / min), that is, 50 m ³ / min, 100 m ³ / min, 150 m ³ / min, 200 m ³ / min, 250, and 300 m ³ / min The total head H is measured while gradually decreasing the water absorption level TP while keeping Q constant. The measurement results are shown in FIG. When the water absorption level TP drops to a specific water level for each of the six types of drainage amount Q, a sudden drop in the total head begins due to the influence of the air-water mixing operation state. For example, when the drainage amount Q is the rated 300 m ³ / min, there is a sudden drop in the total head H at a water absorption level TP of −16.4 m, which is the height position of the air supply port 10a (upper threshold value TP _UP ). Start. As the amount of drainage Q decreases, the amount of air sucked into the casing 5 decreases, so that the water absorption level TP at which a sudden drop in the total lift H starts also decreases. In FIG. 4, a curve L connecting the start points of the rapid drop of the total head H is obtained. FIG. 3 is a graph in which the intersection of the water absorption level TP and the total head H is plotted on the coordinate plane with the horizontal axis indicating the flow rate Q and the vertical axis indicating the water absorption level for the curve L and the six types of flow rates. That is, in this example, the relationship between the water absorption level TP and the water discharge amount Q in the range of TP _UP ≧ TP> TP _LW is the water absorption level TP at which the total head H starts to drop due to the water discharge amount Q and the air-water mixing operation state. It is demanded from the relationship.

In the present embodiment, the drainage amount Q in the range of TP _UP ≧ TP> TP _{LW in} which the decrease in the drainage amount Q occurs due to the air-water mixing operation state is obtained based on the relationship of FIG. Q is not estimated to be excessive (same as the normal drainage operation, which is the rated drainage amount), nor is it estimated to be too small (the drainage amount is zero). Further, it is not necessary to perform a complicated calculation in order to obtain the drainage amount Q in the range of TP _UP ≧ TP> TP _LW . Therefore, the amount Q of drainage can be measured easily and with high accuracy by the method of the present embodiment.

(Second Embodiment)
The second embodiment differs only in the method of measuring the drainage amount Q of the vertical pump 1 executed by the arithmetic device 15, and the structure of the vertical pump 1 itself is the same as that of the first embodiment (see FIG. 1). As shown in Table 2 below, the drainage amount Q of the vertical pump 1 executed by the processing unit 17 is also the same as that of the first embodiment except when the water absorption level TP is in the range of TP _UP ≧ TP> TP _LW. Are the same.

In the present embodiment, when the water absorption level TP is TP _UP ≧ TP> TP _LW , the drainage amount Q is estimated to be a specified drainage amount _QRE that is a predetermined constant drainage amount. This specified drainage amount _QRE needs to be set to be at least smaller than the drainage amount in the normal drainage operation state at the rated drainage amount (300 m ³ / min in this embodiment). Further, if the specified drainage amount _QRE is set to a value close to the drainage amount in the normal drainage operation state, it is estimated that more water is discharged than the drainage amount actually discharged from the water absorption tank 2 by the vertical shaft pump 1. There is a possibility that it is not preferable. Conversely, if the specified drainage amount _QRE is set sufficiently smaller than the drainage amount in the normal drainage operation state, the amount of water that is smaller than the drainage amount actually discharged from the water tank 2 by the vertical shaft pump 1 is discharged. Even if there is a possibility that it is estimated that the water is discharged, it is possible to eliminate the possibility that it is estimated that more water is discharged than the actual amount of waste water. Therefore, the specified drainage amount _QRE is sufficiently smaller than the drainage amount in the normal drainage operation state, specifically, 1/10 or more of the drainage amount in the normal drainage operation state at the rated drainage amount (300 m ³ / min in this embodiment). The drainage amount is set within a range of 1/5 or less. For example, the specified drainage amount _QRE is set to 50 m ³ / min, which is 1/6 of the drainage amount (300 m ³ / min) in the normal drainage operation state at the rated drainage amount.

In the present embodiment, the drainage amount Q in the range of TP _UP ≧ TP> TP _{LW in} which the reduction of the drainage amount Q occurs due to the air-water mixing operation state is set to the specified wastewater amount _QRE , so the wastewater amount in the air-water mixing operation state Q is not estimated to be excessive (same as the normal drainage operation, which is the rated drainage amount), nor is it estimated to be too small (the drainage amount is zero). Further, it is not necessary to perform a complicated calculation in order to obtain the drainage amount Q in the range of TP _UP ≧ TP> TP _LW . Therefore, the amount Q of drainage can be measured easily and with high accuracy by the method of the present embodiment.

  The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the structure of the stand-by type vertical shaft pump is not limited to that shown in FIG. 1, and any structure may be used as long as the air supply port is provided at a position closer to the suction port than the impeller of the casing.

The schematic diagram which shows a prior | preceding standby type | formula vertical shaft pump. The partial enlarged view of a vertical shaft pump. The diagram which shows the relationship between a water absorption level and the amount of drainage. The diagram which shows the relationship between a water absorption level and a total lift about various amounts of drainage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Leading-stand type vertical shaft pump 2 Water absorption tank 3 Discharge water tank 5 Casing 5a Suction port 6 Rotating shaft 7 Impeller 8 Motor 9 Piping 10 Air introduction pipe 10a Air supply port 11 1st water level sensor 12 2nd water level sensor 15 Calculation apparatus 16 Memory | storage Unit 17 Processing unit 18 Display device

Claims (6)

A method of measuring the amount of drainage in which the standby stand-by vertical pump having an air supply port at a position closer to the suction port than the impeller of the casing drains the water in the water absorption tank to the discharge water tank,
The water absorption level that is the water level of the water absorption tank is measured by a first water level sensor,
A discharge water level which is a water level of the discharge water tank is measured by a second water level sensor;
If the water absorption level measured by the first water level sensor is at a position closer to the suction port than the front edge of the impeller and exceeds the upper threshold value which is the water level corresponding to the air supply port, The water absorption level measured by the first water level sensor, the discharge water level measured by the second water level sensor, the relationship between the total head in the normal drainage operation state measured in advance and the amount of drainage, and the pipe measured in advance Calculate the emissions based on road resistance,
If the water absorption level measured by the first water level sensor is less than or equal to the upper threshold value and exceeds a lower threshold value that is a predetermined water level above the water level of the suction port, the water absorption measured in advance Calculating the amount of wastewater using the relationship between the position and the amount of wastewater,
If the water absorption level measured by the first water level sensor is equal to or lower than the lower threshold value, the drainage amount measuring method for a stand-by type vertical shaft pump that sets the drainage amount to zero .   The preceding standby according to claim 1, wherein the lower threshold value is a water level in which a loss of air flowing into the casing from the suction port and a loss of air flowing into the casing from the air supply port are balanced. Drainage measurement method for vertical shaft pump.   The prior standby according to claim 1 or claim 2, wherein the relationship between the water absorption level and the amount of drainage is obtained from the relationship between the amount of water discharge and the water absorption level at which the drop of the total lift starts due to the mixed operation state. Drainage measurement method for vertical shaft pump. A method of measuring the amount of drainage in which the standby stand-by vertical pump having an air supply port at a position closer to the suction port than the impeller of the casing drains the water in the water absorption tank to the discharge water tank,
The water absorption level that is the water level of the water absorption tank is measured by a first water level sensor,
A discharge water level which is a water level of the discharge water tank is measured by a second water level sensor;
If the water absorption level measured by the first water level sensor is at a position closer to the suction port than the front edge of the impeller and exceeds the upper threshold value which is the water level corresponding to the air supply port, The water absorption level measured by the first water level sensor, the discharge water level measured by the second water level sensor, the relationship between the total head in the normal drainage operation state measured in advance and the amount of drainage, and the pipe measured in advance Calculate the emissions based on road resistance,
If the water absorption level measured by the first water level sensor is equal to or lower than the upper threshold value and exceeds a lower threshold value that is a predetermined water level above the water level of the suction port, the discharge amount is determined in advance. Specified sewage amount,
If the water absorption level measured by the first water level sensor is less than or equal to the lower threshold, the amount of drainage is set to zero.
A method for measuring the amount of water discharged from a stand-by type vertical shaft pump.   The preceding standby according to claim 4, wherein the lower threshold is a water level in which a loss of air flowing into the casing from the suction port and a loss of air flowing into the casing from the air supply port are balanced. Drainage measurement method for vertical shaft pump.   6. The method for measuring the amount of drainage of a stand-by type vertical shaft pump according to claim 4 or 5, wherein the specified amount of drainage is set in a range of 1/10 to 1/5 of the amount of drainage in the normal drainage operation state.

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