JPH03217696A - Operating method of vertical shaft pump - Google Patents

Abstract

PURPOSE:To increase water storing amount and to prevent generation of a flood by providing an elevating means to move a main shaft up and down, and a water level detecting means to output a signal and operate the elevating means. CONSTITUTION:By the operation of an elevating means 9 to operate depending on the water level signal from a water level detecting means 8, a main shaft 1 is moved up and down. When the water level WL is at the lowest water level LWL or higher, the main shaft 1 is positioned at its lowest position, and the amount of the vane clearance 6 is set to a standard value W1 to allow a normal pumping-out operation. When the water level WL is decreased to less than the lowest water level LWL, the main shaft 1 is positioned at the uppermost position, and the amount of the vane clearance 6 is set to an expanded value to allow a small amount of pumping-out operation. In such a way, the water storing amount is increased, and a flood generating condition can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vertical shaft pump used in pump intake wells and rainwater pump equipment of drainage pumping stations installed mainly for draining waterways during floods. Regarding how to drive. [Conventional technology] Traditionally, general vertical shaft pumps installed in pump water intake wells of drainage pump stations, etc., generate vortices when the water level is lower than a certain level, even though the suction port is underwater. There is a minimum water level specific to each pump, such as air-mixed water being sucked into the pump, and if the pump is operated when the water level is lower than this minimum water level, air suction vortices and breathing phenomena may occur. It has the characteristic of causing vibrations and noise. Therefore, if such a general vertical shaft bomb is operated at full speed regardless of the water level in the water suction well and left on standby in case of an unexpected water outflow, it will cause severe vibration when the water level is below the minimum water level. There is a risk that such noise may cause problems such as malfunction of pump operation or damage to the foundation or building. Therefore, conventional vertical shaft pumps do not perform full-speed standby operation, but operate only when the water level is higher than the minimum water level, and stop operation when the water level is lower than the minimum water level. ．． [Problem to be solved by the invention] However, in recent years, the water retention function of the stratum has been decreasing due to an increase in paving ratio and a decrease in green areas due to the progress of urbanization, and the amount of water flowing into the water absorption wells etc. has decreased. In addition, large amounts of water suddenly and suddenly flow into water intake wells, such as in so-called flash floods, which frequently occur. Therefore, in water intake wells, etc., the water level fluctuates in a short period of time, and the above-mentioned operation system using conventional vertical shaft pumps cannot accurately control the operation start timing and operation stop timing of the vertical shaft pump, and the water level fluctuates rapidly. There were concerns that the water would rise abnormally and cause flooding. The present invention was developed in view of the above circumstances, and the above-mentioned inconvenience does not occur even if the water level drops below the minimum water level. The purpose of this invention is to provide a method for operating a vertical shaft pump that lowers the water level to a level below the minimum water level, increases the amount of water stored, and prevents flooding due to an abnormal rise in the water level. [Means for Solving the Problem] In order to achieve the above object, the present invention provides an impeller that is fixed to a main shaft and is rotatably installed in an impeller chamber, and a discharge casing and a suction are arranged above and below the impeller chamber. A vertical shaft pump in which casings are connected to each other is provided with an elevating means for elevating and lowering the main shaft, and a water level detecting means for outputting a signal to the elevating means to operate the elevating means, and based on a water level detection signal from the water level detecting means, When the water level is higher than the lowest water level of the vertical shaft pump, the main shaft is positioned at the lower limit position by the lifting means, and the amount of blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber is reduced. When the water level is lower than the minimum water level of the vertical shaft pump, the main shaft is positioned at the upper limit position by the lifting means, and the amount of the blade gap is set to a value that is possible for drainage operation. This is set to the enlarged value. [Function] According to the present invention, when the water level in a water absorption well or the like is higher than the minimum water level, this water level is detected by the water level detection means, and a detection signal from there is input to the elevating means to operate the elevating means. Let. As a result, the main shaft is pushed down and positioned at the lower limit position, the amount of blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber is set to a standard value that allows normal drainage operation, and the vertical shaft pump perform normal drainage operation. When the water level in the water suction well, etc. drops to a level below the minimum water level due to the continuation of the drainage operation, this water level is detected by the water level detection means, and a detection signal from there is input to the lifting means to operate the lifting means. As a result, the main shaft is pushed up and positioned at the upper limit position, and the amount of the blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber is set to an enlarged value that allows small-drain operation. A small amount of drainage operation is performed. [Example] Hereinafter, an example of the present invention will be described based on the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention. In the figure, a vertical shaft bomb includes a main shaft 1, an impeller 2 fixed to the main shaft 1, and an impeller in which the impeller 2 is rotatably installed. Room 3
It is composed of a discharge casing 4 and a suction casing 5 which are connected to the upper and lower sides of the impeller chamber 3, and the discharge casing 4 is composed of a lift pipe 4A and a discharge side elbow 4B, and includes the outer periphery of the impeller 2 and the blades. A blade gap 6 is formed between the blade and the inner circumference of the vehicle compartment 3. At all times, the amount of the blade gap 6 is set to a reference value W1 that allows normal drainage operation. The upper end of the main shaft l is simultaneously rotatably connected to a drive source (not shown) by a coupling 7 that allows movement in the axial direction, and is actuated based on a water level detection signal from a water level detection means 8. The main shaft 1 is raised and lowered by the operation of the lifting means 9. That is, the water level detection means 8 is composed of a well-known water level gauge 8A and a signal line 8B that outputs a water level detection signal from this to the elevating means 9, and the elevating means 9 has a control section 90 and a driving section 9l. Based on the signal input to the control unit 90 through the signal line 8B, the control unit 90 connects the path 10A to the IO.
A driving medium such as pressurized oil is supplied to the upper chamber 91A or lower chamber 91B of the drive unit 9l through B, and loads the upper or lower surface of the flange (piston) IA formed on the main shaft 1. It has become. Next, the operation of the above configuration will be explained. As shown in FIG. 1, when the water level WL of the water intake well P is higher than the lowest water level LWL, this water level WL is detected by the water level meter 8A of the water level detection means 8, and this detection signal is sent to the signal line 8B.
is inputted to the control unit 90 of the lifting means 9 via. As a result, the drive unit 9l is transferred from the control unit 90 through the passage 10A.
A driving medium such as pressure oil is supplied to the upper chamber 91A, and is applied to the upper surface of the flange (piston part) LA formed on the main shaft l, pushing down the flange IA, positioning the main shaft l at the lower limit position, and rotating the blade. The amount of the blade gap 6 formed between the outer periphery of the wheel 2 and the inner periphery of the impeller chamber 3 is set to a reference value W1 that allows normal drainage operation. Therefore, the vertical shaft pump 1 performs normal drainage operation. As the water drainage operation continues, as shown in FIG. 2, when the water level WL of the water suction well P falls to a level below the lowest tree level I, WL, this water level WL is detected by the water level meter 8A of the water level detection means 8, This detection signal is input to the control section 90 of the elevating means 9 via the signal line 8B. As a result, a driving medium such as pressure oil is supplied from the control section 90 to the lower chamber 91B of the driving section 9l through the passage IOB, and is loaded onto the lower surface of the flange (piston section) IA formed on the main shaft 1. Push up the flange IA and position the main shaft l to the upper limit position,
The amount of the blade gap 6 formed between the outer periphery of the impeller 2 and the inner periphery of the impeller chamber 3 is set to an enlarged value W2 that is at least 10 times larger than the W1, that is, a small amount of drainage operation is possible. do. In this way, even if the vertical shaft pump l is operated at full speed with the amount of the blade gap 6 expanded, leakage from the blade gap will increase and the amount of water discharged will decrease as a result. No vortices or breathing phenomena occur, and therefore, the generation of severe vibrations and noise is avoided, and inconveniences such as malfunctioning pump operation and damage to foundations and buildings are prevented. Moreover, by lowering the water level WL of the water intake well P to the lowest tree level LWL unedged level, the amount of water stored increases accordingly, so there is sufficient margin against abnormal rises in water level due to sudden inflow of rainwater. You can respond with Furthermore, in the above embodiment, the blade gap 6 (W2) is constant at a water level below LWL, but the gap is increased continuously from W1 to W2 as the water level decreases from LWL. You can. [Advantageous Effects of the Invention 1] Since the present invention is configured as described above, it produces the effects described below. That is, when the water level of the water intake valve, etc. is at a level higher than the minimum water level, this water level is detected by the water level detection means, and a detection signal from there is input to the elevating means to operate the elevating means. the result,
Push down the main shaft to position it at the lower limit position, set the amount of blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber to a reference value that allows normal drainage operation, and set the vertical shaft pump to the normal Perform drainage operation. Furthermore, when the water level in the water intake well, etc. drops to a level below the minimum water level due to the continuation of the drainage operation, this water level is detected by the water level detection means, and a detection signal from there is input to the elevating means to operate the elevating means. Let. As a result, the main shaft is pushed up and positioned at the upper limit position, and the amount of the blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber is set to an enlarged value that allows for small-dose drainage operation. Since the pump can perform a small amount of drainage operation, unlike conventional pumps, air suction vortices and breathing phenomena do not occur, and the generation of severe vibrations and noise is avoided, which may cause pump operation malfunctions. This prevents inconveniences that could damage the foundation or building. Furthermore, by lowering the water level in water intake wells, etc. to a level below the minimum water level, the amount of water stored increases accordingly, so there is sufficient margin to cope with abnormal rises in water level due to sudden inflow of rainwater. Can be done.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of the device in a normal drainage operation state, and FIG. 2 is a longitudinal sectional front view of a small amount drainage operation state. 1... Main shaft 2... Impeller main body... Impeller chamber 4... Discharge casing 5... Suction casing 6... Blade gap 8... Water level detection means 9... Lifting means W1 ...Reference value of blade gap amount W2...Enlarged value of blade gap amount WL...Water level LWL...Minimum water level

Claims (1)

[Claims] In a vertical shaft pump in which an impeller fixed to a main shaft is rotatably housed in an impeller chamber, and a discharge casing and a suction casing are connected in communication with each other above and below the impeller chamber, a lifting means for raising and lowering the main shaft; A water level detection means is provided which outputs a signal to the lifting means to operate it, and when the water level is higher than the lowest water level of the vertical shaft pump based on the water level detection signal from the water level detection means, the lifting means moves the main shaft to the lower limit position. The amount of blade gap formed between the outer periphery of the impeller and the inner periphery of the impeller chamber is set to a standard value that allows normal drainage operation, and the water level is below the lowest water level of the vertical shaft pump. A method for operating a vertical shaft pump, characterized in that when the main shaft is at the level, the main shaft is positioned at the upper limit position by means of a lifting means, and the amount of the blade gap is set to an enlarged value that allows a small amount of drainage operation.