JP2014043838A - Feed-water pump and full water level detecting method of feed-water pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a feed-water pump and a full water level detecting method of the feed-water pump capable of properly judging whether an internal part of a pump body arrives at a full water level when performing the priming water even in the case of pumping up sea water, lake water or the like.SOLUTION: A feed-water pump which pumps up water from a water storage body and feeds the water to an external part comprises: a pump body; a water suction pipe through which the water is pumped up into the pump body from the water storage body; an air intake pipe which sucks and evacuates the internal part of the pump body; and a service water feed pipe which feeds the water to the external part from the internal part of the pump body. Therein, an air intake port as a connection part between the pump body and the air intake pipe is located above the pump body, a water suction port as a connection part between the pump body and the water suction pipe is located under the pump body and is provided with a means for measuring a differential pressure between a pressure in the air intake pipe and a pressure in the water suction pipe and can detect that the internal part of the pump body becomes full of water in the pump body from circumstances of fluctuation of the differential pressure when performing the priming water before operation of the feed-water pump.

Description

  The present invention relates to a water supply pump for supplying water pumped up from a water storage body such as a sea or a lake to a desired facility, and a full water detection method for the water supply pump.

  A water supply device that supplies cooling water to a cooling device that cools these facilities is an important facility in order to prevent the melting of the tuyere in the blast furnace and the combustion dissipation due to insufficient gas cooling of the coke oven. This cooling water is generally supplied from a water storage body such as the sea or a lake through a water supply pump.

  The feed water pump as described above cannot pump water in a state where a certain amount or more of gas exists in the pump body. Therefore, before the operation of the water supply pump, the vacuum pump sucks (depressurizes) the inside of the pump main body of the water supply pump to pump water into the pump main body (this operation is referred to as “expiration”), and the pump main body. The inside is filled with water (hereinafter, this state is referred to as “full water (state)”).

  Several techniques for detecting that the inside of the pump body of the water supply pump has become full when performing the above-described exhalation have been disclosed. For example, Patent Document 1 below discloses a technique for preventing an operation failure caused by foreign matter entangled with a float or an electrode rod in a full water detector.

Japanese Patent Laid-Open No. 11-230050

  However, when it is assumed that water is pumped up from the sea or lake with a water supply pump, the conventional technique as described in Patent Document 1 described above has insufficient measures. When pumping water from the sea or lake with a water pump, the following problems are likely to occur because the pumped water contains fine foreign matter and salt. That is, when the full water detector is a float type, there is a possibility that a foreign matter or salt adheres to a spindle or the like which is a sliding portion and a sliding failure occurs. Further, in the case of the electrode type, there is a possibility that a short circuit occurs due to adhesion of salt, and full water cannot be detected.

  Therefore, the present invention provides a water supply pump capable of appropriately detecting whether or not the inside of the pump body has reached full water when performing exhalation even when pumping seawater, lake water, or the like, and a full water detection method for the water supply pump. This is the issue.

  By detecting the water head pressure when the pump body of the feed water pump is full, it can be determined in principle that the pump body is full. However, when water is pumped from the reservoir by the water supply pump, the head pressure changes depending on the water level of the reservoir. Further, when exhalation is performed using a vacuum pump, the pressure loss inside the feed water pump is large, and it is difficult to detect only the water head pressure.

  Then, this inventor considered losing the influence of the water level of a reservoir by detecting the differential pressure of the upper part and the lower part of a water supply pump. Moreover, this inventor discovered that the pressure loss inside a feed pump fluctuate | varies according to the change of the water level of a water storage body by performing a test on various conditions. Furthermore, it was found that it was possible to judge that the inside of the pump body was full from the fluctuation state of the differential pressure between the upper part and the lower part of the feed pump. This invention is made | formed based on the said knowledge.

  A first aspect of the present invention is a full-water detection method for a water supply pump that pumps water from a water reservoir and supplies the water to the outside. The water supply pump pumps water from the water reservoir into the pump main body. The pump has a water intake pipe to be pumped up and an air intake pipe that sucks and decompresses the inside of the pump body, and an intake port that is a connection portion between the pump body and the intake pipe is located at the upper part of the pump body, and The water inlet, which is the connection to the pipe, is located at the lower part of the pump body, and measures the differential pressure between the pressure in the intake pipe and the pressure in the water intake pipe when performing the exhalation before the operation of the water supply pump. This is a water supply pump full detection method for detecting that the pump body is full from the pressure fluctuation.

  In the present invention, “before operation of the water supply pump” means before the water pumped up from the water reservoir is supplied to a desired facility.

  The second aspect of the present invention is a water supply pump that pumps water from a water reservoir and supplies the water to the outside. The pump main body, a water absorption pipe that pumps water from the water reservoir into the pump main body, and a pump It has an intake pipe that sucks the inside of the main body and decompresses it, and a water supply pipe that supplies water from the inside of the pump body to the outside, and the intake port that connects the pump body and the intake pipe is the upper part of the pump body The water inlet, which is the connection between the pump body and the water suction pipe, is located at the lower part of the pump body, and has means for measuring the differential pressure between the pressure in the suction pipe and the pressure in the water suction pipe. It is a water supply pump which can detect that the inside of a pump main body is full from the fluctuation | variation state of the said differential pressure when performing exhalation before a driving | operation.

  In the second aspect of the present invention described above, it is preferable to provide means for starting the supply of water to the outside through the water supply pipe based on the detection that the inside of the pump body is full.

  In the second aspect of the present invention, it is preferable to provide a water stop device that prevents the water from flowing from the pump body to the intake pipe when the water level in the pump body reaches a predetermined height or more.

  Furthermore, in the second aspect of the present invention, the means for measuring the differential pressure between the pressure in the intake pipe and the pressure in the water absorption pipe is preferably a diaphragm type pressure gauge.

  ADVANTAGE OF THE INVENTION According to this invention, even when pumping up seawater, lake water, etc., when performing exhalation, the water supply pump which can detect appropriately whether the inside of a pump body has reached full water, and the full water detection method of the water supply pump Can be provided.

It is the figure which showed the structure of the water supply pump 10 roughly. It is the figure which showed the time change of the differential pressure | voltage between the pressure in an intake pipe at the time of performing exhalation, and the pressure in a water absorption pipe. It is the figure which showed the relationship between the water level of a water storage body, and the pressure difference between the pressure in an intake pipe, and the pressure in a water absorption pipe. 4 (A) and 4 (B) are flowcharts schematically showing the flow of the operation preparation method for the feed water pump.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram schematically showing the configuration of a water supply pump 10 which is one embodiment of the water supply pump of the present invention.

  The water supply pump 10 is a pump that draws water from the water reservoir 20 and supplies the water to the outside. As shown in FIG. 1, the water supply pump 10 includes a pump main body 1, a water intake pipe 2 that pumps water into the pump main body 1 from the water storage body 20, an intake pipe 3 that sucks the inside of the pump main body 1 and decompresses it, And a water supply pipe 4 for supplying water from the inside of the pump body 1 to the outside. The water supply pump 10 further includes means 6 (differential pressure gauge 6) for measuring a differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2. As will be described in detail later, When exhalation is performed before operation, it can be detected from the fluctuation state of the differential pressure measured by the differential pressure gauge 6 that the inside of the pump body 1 is full.

  The pump body 1 has an opening 2a (hereinafter referred to as “water intake port 2a”) that is a connection portion with the water suction pipe 2 and an opening portion 3a (hereinafter referred to as “intake port 3a”) that is a connection portion with the intake pipe 3. And an opening 4 a (hereinafter referred to as “water supply port 4 a”) that is a connection portion with the water supply pipe 4. The intake port 3 a is located in the upper part of the pump body 1, and the water intake port 2 a is located in the lower part of the pump body 1 and higher than the water level of the water reservoir 20.

  One end of the water absorption pipe 2 is connected to the pump body 1 through a water inlet 2 a, and the other end is a cylindrical body immersed in the water storage body 20. When exhalation is performed before the operation of the water supply pump 10, if the pressure inside the pump body 1 is reduced, water is pumped from the water reservoir 20 into the pump body 1 through the water suction pipe 2.

  One end of the intake pipe 3 is connected to the pump body 1 through an intake port 3a, and the other end is a cylindrical body connected to a vacuum pump (not shown). When exhalation is performed before the feed water pump 10 is operated, by operating the vacuum pump, it is possible to intake air from the inside of the pump body 1 through the intake pipe 3 and decompress the inside of the pump body 1. The intake pipe 3 is provided with an intake valve 3c. By operating a vacuum pump connected to the intake pipe 3 and opening the intake valve 3c, it is possible to intake air from within the pump body 1. Further, by closing the intake valve 3c, the flow of fluid in the intake pipe 3 can be stopped.

  The intake pipe 3 is provided with a water stop 3b. The water stop 3b can prevent water from flowing into the intake pipe 3 from the pump body 1 when the water level in the pump body 1 reaches a predetermined height or more. As such a water stop 3b, a well-known float valve can be used, for example.

  One end of the water supply pipe 4 is connected to the pump body 1 through a water supply port 4a, and the other end is a cylindrical body connected to desired equipment for supplying water pumped up by the water supply pump 10. The water pumped up by the water supply pump 10 from the water reservoir 20 can be supplied to desired equipment through the water supply pipe 4. The water supply pipe 4 is provided with a water control valve 4b. By controlling the opening / closing of the water control valve 4b, the amount of water supplied to a desired facility connected to the water supply pipe 4 can be controlled. it can.

  The differential pressure gauge 6 is not particularly limited as long as it can measure the differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2. In this embodiment, the pipe 5 connected to the differential pressure gauge 6 is connected to the predetermined position 3x of the intake pipe 3 and the predetermined position 2x of the water absorption pipe 2, respectively, so that the pressure in the intake pipe 3 and the water absorption pipe 2 Measure the differential pressure from the pressure. In this example, the differential pressure gauge 6 is preferably a diaphragm type pressure gauge. This is because the diaphragm type pressure gauge is not exposed to the sliding portion or the electrode portion, so that sliding failure or short circuit does not occur.

  As a means for measuring the differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2, for example, a predetermined position 3 x of the intake pipe 3 and a predetermined position 2 x of the water absorption pipe 2 can be used. This difference may be obtained after each pressure gauge is attached to each and the respective pressures are measured. The pressure gauge in this case is also preferably a diaphragm type pressure gauge.

  Moreover, although not shown in figure, it is preferable that the water supply pump 10 is provided with a means to start supply of the water through the water supply pipe 4 based on having detected that the inside of the pump main body 1 is full. . As such means, for example, the opening / closing of the water control valve 4b can be controlled based on the measurement result by the differential pressure gauge 6 (fluctuation state of the differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2). A control device can be mentioned. The control device includes, for example, a CPU capable of calculating the operation amount of the water control valve 4b from the measurement result of the differential pressure gauge 6 and executing operation control of the water control valve 4b, and a storage device for the CPU. Can be configured. The CPU is configured by combining a microprocessor unit and various peripheral circuits necessary for the operation thereof, and a storage device for the CPU stores, for example, programs and various data necessary for operation amount calculation and operation control of the water control valve 4b. A ROM that stores data and a RAM that functions as a work area for the CPU are combined. In addition to this configuration, the CPU of the control device can be appropriately controlled with respect to the operation of the water control valve 4b by being combined with the software stored in the ROM. In the feed water pump 10, a signal output from the differential pressure gauge 6 toward the control device reaches the CPU as an input signal via the input port of the control device. The CPU of the control device calculates the operation amount of the water control valve 4b based on the input signal and the program stored in the ROM of the control device, and outputs an operation command to the water control valve 4b via the output port of the control device. To do.

  The water storage body 20 is not particularly limited as long as it can supply a sufficient amount of water when supplying water to a desired facility by the water supply pump 10. Examples of the water reservoir 20 include the sea and a lake. According to the water supply pump 10, when exhalation is performed, it is possible to prevent the determination of whether or not the inside of the pump body 1 is full due to fine foreign matters and salt contained in the pumped water. Therefore, according to the water supply pump 10, even when pumping up water containing fine foreign matter or salt, such as seawater or lake water, whether or not the inside of the pump body 1 has reached the full level when exhaling water is appropriately determined. The water can be determined and can be stably supplied to the desired equipment.

  Next, a full water detection method of the feed water pump 10 for detecting that the inside of the pump body 1 is full when exhalation is performed before the operation of the feed water pump 10 is started will be described below.

  The water supply pump 10 measures the differential pressure between the pressure in the intake pipe 3 and the pressure in the water intake pipe 2 when exhaling water before operation, and the pump body 1 is filled with water from the fluctuation state of the differential pressure. Can be detected. The differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2 can be measured by the differential pressure gauge 6 as described above. A method for detecting that the inside of the pump body 1 is full from the fluctuation state of the differential pressure will be described in detail below.

  By detecting the water head pressure when the inside of the pump body 1 of the feed water pump 10 is full, it can be determined in principle that the inside of the pump body 1 is full. However, when water is pumped from the water reservoir 20 by the water supply pump 10, the water head pressure changes depending on the water level of the water reservoir 20. Further, when exhalation is performed using a vacuum pump connected to the intake pipe 3, the pressure loss inside the water supply pump 10 is large, and it is difficult to detect only the water head pressure. Then, this inventor considered losing the influence of the water level of the reservoir 20 by detecting the differential pressure between the upper part and the lower part of the water supply pump 10. Moreover, this inventor discovered that the pressure loss inside the feed water pump 10 fluctuate | varies according to the change of the water level of the water storage body 20 by performing a test on various conditions. Furthermore, it discovered that it could be judged from the fluctuation | variation state of the differential pressure of the upper part of the feed water pump 10 and the lower part that the inside of the pump main body 1 became full.

  Specifically, the pipes 5 and 5 connected to the differential pressure gauge 6 are respectively connected to predetermined positions 3x and 2x of the intake pipe 3 at the upper part of the pump body 1 and the water absorption pipe 2 at the lower part, respectively. The pressure difference between the pressure in the pipe 3 and the pressure in the water absorption pipe 2 is measured. FIG. 2 is a diagram showing the change over time in the differential pressure between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2 when performing exhalation. The horizontal axis of the graph shown in FIG. 2 is the time [seconds] from the start of the vacuum pump connected to the intake pipe 3, and the vertical axis represents the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2. The differential pressure [kPa].

  In the graph shown in FIG. 2, the vacuum pump is started at time I, water reaches the water inlet 2a at time II, and water reaches the upper portion of the pump body 1 (air inlet 3a) at time III. It is considered that water has reached the predetermined position 3x of the intake pipe 3 at the time of IV, and the water stop 3b has been closed at the time of V. In the section from I to II, pressure loss due to air flowing in the feed water pump is observed. In the section of II to III, it is considered that the water level is rising from the predetermined position 2x of the water absorption pipe 2. In the section of III to IV, the diameter of the intake pipe 3 is narrower than the capacity of the pump body 1, so the water level is considered to have increased rapidly. In the section of IV to V, it is considered that the flow of water to the intake pipe 3 is stopped by the float of the water stop 3b floating, and the pressure loss is reduced.

  As shown in FIG. 2, the differential pressure increases rapidly in about 68 seconds to about 70 seconds (section III to IV) after starting the vacuum pump. Specifically, the slope of the time variation of the differential pressure from the time point III changes from 0.64 kPa / second to 7.00 kPa / second. This is considered to be because the diameter of the intake pipe 3 is smaller than the capacity of the pump body 1, so that the water level rapidly rises and the pressure loss rapidly increases. From this, it can be seen that the water pumped from the water reservoir 20 reaches the intake pipe 3 at about 68 seconds (III) after the vacuum pump is started. Thus, since the differential pressure increases rapidly after the inside of the pump body 1 becomes full, the degree of change in the gradient of the differential pressure is set as a threshold value for determining that the inside of the pump body 1 is full. Can do. Therefore, it can be determined that the inside of the pump body 1 is full when the slope of the time variation of the differential pressure exceeds a predetermined value.

  In addition, the differential pressure at the point of time when the slope of the temporal change of the differential pressure suddenly increases (time point III) (hereinafter referred to as “the differential pressure at the inflection point”) and the maximum differential pressure (IV The intermediate value with the differential pressure at the time point can also be a threshold value for determining that the inside of the pump body 1 is full.

  However, due to the characteristics of the vacuum pump, when the water head pressure changes due to the fluctuation of the water level of the water reservoir 20, the air suction amount changes, and the pressure loss changes accordingly. That is, since the differential pressure changes due to fluctuations in the water level of the reservoir 20, repeated experiments are performed under various conditions to obtain a large number of values of the differential pressure at the inflection point and the maximum differential pressure in the priming process. A more appropriate threshold value that can be judged to be full in 1 was examined.

  FIG. 3 is a diagram showing the differential pressure at the inflection point, the maximum differential pressure in the expiratory process, and the intermediate value between the two with respect to the water level of the reservoir 20. As shown in FIG. 3, the intermediate value between the differential pressure at the inflection point and the maximum differential pressure in the expiration process varies depending on the water level of the reservoir 20. Therefore, it is considered preferable to use a value obtained by averaging the plurality of intermediate values when the water levels of the water storage bodies 20 are different as the threshold value for determining that the pump body 1 is full.

  The above threshold value for determining that the inside of the pump body 1 is full varies depending on the pressure loss inside the pump that is actually used and the detection position of the pressure, as well as the ability of the vacuum pump that sucks the inside of the pump body. Therefore, an appropriate threshold value needs to be set for each actually used feed water pump or a combination of a feed water pump and a vacuum pump.

  FIG. 4 (A) and FIG. 4 (B) schematically show the flow of the full water detection method of the feed water pump that determines that the inside of the pump body 1 is full from the fluctuation state of the differential pressure as described above. It is a flowchart.

  The method illustrated in FIG. 4A includes a vacuum pump activation step S11 and a full water determination step S12. The vacuum pump starting step S11 is a step of starting the vacuum pump connected to the intake pipe 3 and depressurizing the inside of the pump body 1. By depressurizing the inside of the pump body 1, water is pumped from the water reservoir 20 into the pump body 1 through the water absorption pipe 2. In the full water determination step S12, after the water starts to be pumped into the pump body 1 as described above, the gradient of the time variation of the pressure difference between the pressure in the intake pipe 3 and the pressure in the water absorption pipe 2 is a predetermined threshold value. This is a step of determining whether or not As described above, whether or not the inside of the pump body 1 is full can be determined based on whether or not the slope of the time-dependent change in the differential pressure has reached a predetermined threshold value. The determination may be performed by an operator, or an apparatus that can determine automatically may be used. The full water determination step S12 is repeated until the gradient of the time variation of the differential pressure reaches a predetermined threshold. If it is determined that the predetermined threshold has been reached, the water supply pump 10 is activated to supply water to a desired facility. Can do.

  The method illustrated in FIG. 4B is the same except that the content of the full water determination step S22 is different from the full water determination step S12 of the method illustrated in FIG. Therefore, only the full water determination step S22 will be described for the method illustrated in FIG. In the full water determination step S22, as described above, an intermediate value between the differential pressure at the inflection point and the maximum differential pressure in the expiration process is obtained as a threshold value, and the pressure in the intake pipe 3 and the pressure in the intake pipe 2 are calculated. This is a step of determining whether or not the differential pressure has reached the threshold value. As described above, depending on whether or not the differential pressure between the pressure in the intake pipe 3 and the pressure in the water intake pipe 2 has reached an intermediate value between the differential pressure at the inflection point and the maximum differential pressure in the expiration process, It can be determined whether the inside of the pump body 1 is full. The full water determination step S22 is repeated until the differential pressure reaches the intermediate value, and if it is determined that the intermediate value has been reached, the water supply pump 10 can be activated to supply water to the desired equipment.

  As explained so far, according to the present invention, it is determined that the inside of the pump body is full from the fluctuation state of the differential pressure between the upper part and the lower part of the feed water pump, and it is as fine as seawater or lake water. Even when pumping up water containing foreign matter or salt, it is possible to appropriately determine whether or not the inside of the pump body has reached full water at the time of expiration. Therefore, according to the water supply apparatus using the water supply pump of the present invention, the cooling water can be stably supplied to a cooling apparatus that cools a desired apparatus such as a blast furnace or a coke oven.

DESCRIPTION OF SYMBOLS 1 Pump main body 2 Water intake pipe 2a Water intake port 3 Intake pipe 3a Air intake port 3b Water stop 3c Intake valve 4 Water supply pipe 4a Water supply port 4b Water control valve 6 Differential pressure gauge 10 Water supply pump 20 Water storage body

Claims (5)

A full water detection method for a water supply pump that pumps water from a reservoir and supplies the water to the outside.
The water supply pump includes a pump body, a water intake pipe that pumps water into the pump body from the water reservoir, and an intake pipe that sucks and decompresses the inside of the pump body,
An intake port that is a connection portion between the pump body and the intake pipe is located at an upper portion of the pump body, and a water intake port that is a connection portion between the pump body and the water absorption pipe is located at a lower portion of the pump body. ,
When performing exhalation before operation of the water supply pump, measure the differential pressure between the pressure in the intake pipe and the pressure in the water intake pipe,
A full water detection method for a water supply pump, wherein the pump main body is detected to be full from the fluctuation state of the differential pressure. A water supply pump that pumps water from a reservoir and supplies the water to the outside.
A pump body, a water suction pipe for pumping water from the water reservoir into the pump body, an intake pipe for sucking and depressurizing the inside of the pump body, and a water supply pipe for supplying the water from the pump body to the outside , And
An intake port that is a connection portion between the pump body and the intake pipe is located at an upper portion of the pump body, and a water intake port that is a connection portion between the pump body and the water absorption pipe is located at a lower portion of the pump body. ,
Means for measuring a pressure difference between the pressure in the intake pipe and the pressure in the water intake pipe;
A water supply pump capable of detecting that the inside of the pump body is full from the fluctuation state of the differential pressure when exhalation is performed before the operation of the water supply pump.   The water supply pump according to claim 2, further comprising means for starting the supply of water to the outside through the water supply pipe based on the detection that the inside of the pump body is full.   The water supply pump according to claim 2 or 3, further comprising a water stop device that prevents water from flowing from the pump body to the intake pipe when a water level in the pump body reaches a predetermined height or more.   The water supply pump according to any one of claims 2 to 4, wherein the means for measuring the differential pressure is a diaphragm type pressure gauge.