JPH11270773A - Piping structure about reciprocating pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To operate a reciprocating pump continuously or without interruption even if the air quantity of a pressure tank drops, by replenishing the pump with air. SOLUTION: A pipeline 3 connected to the downstream side of a reciprocating pump P for force-feeding fluid is provided with a pressure tank 5 situated near the reciprocating pump P. The pressure tank 5 is provided with a contact-type pressure gauge 7 for detecting the pressure of an air chamber 6 defined in the pressure tank 5 and transmitting corresponding signals to a controller 8. At least a pipeline 2 connected up to the upstream side of the reciprocating pump P is provided with an air intake pipeline 15, in which a stop valve 17 is disposed in electrical connection with the controller 8 so as to open the pipeline 15 in accordance with the signals that the pressure gauge 7 outputs and lead air into the pipeline 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piping structure around a reciprocating pump for intermittently pumping a fluid by a reciprocating motion of a plunger or the like.

[0002]

2. Description of the Related Art Conventionally, as a piping structure around a reciprocating pump for intermittently pumping a fluid such as water or industrial chemicals by reciprocating motion of a plunger or the like of this kind, there is, for example, a piping structure shown in FIG. The reciprocating pump, for example, a plunger pump P is connected to a suction pipe 2 connected to a water tank 1 provided buried in the ground GL on the upstream side on the suction side and a downstream water supply facility on the discharge side. Is connected to the discharge pipe 3 connected to the discharge pipe 3. The reciprocating pump P is provided at a height H1 above the water surface of the water tank 1. Also, this discharge line 3
A pressure tank 5 having a predetermined capacity is connected to a predetermined position close to the plunger pump P through a branch pipe 4, and the pressure tank 5 has a water surface h at a predetermined water level, Has an air chamber 6 formed therein. The pressure tank 5 is provided with a pressure gauge 7 with a contact. The pressure gauge 7 with a contact is relayed to a control device 8, and the control device 8 controls the pressure tank 5 through the pressure gauge 7 with a contact. The pressure in the air chamber 6 is detected, and the plunger pump P is turned on / off by a signal from the pressure gauge 7 with a contact. A drain valve 9 is provided on the bottom side of the pressure tank 5, and a valve 10 connected to an air compressor (not shown) is provided on the upper side.
When water is pumped by the plunger pump P, the pressure tank 5 provided in this manner serves as a cushion in which air in the air chamber 6 serves as a cushion, and the direct pressure of the plunger pump P is used as a pressure gauge 7.
In addition, it has a service to alleviate impact on other pipelines and the like.

[0003]

However, in this pressure tank 5, the amount of air gradually decreases with time during the operation of the plunger pump P. In this case,
As shown in FIG. 2 (A) (based on the actual measurement data), the maximum set pressure in the pressure tank 5 is set to 6 kgf / cm2.
With the lower limit set at 4 kgf / cm2, when the plunger pump P runs over the operating time, the air chamber 6
The maximum set pressure is 6kgf / as shown by A1, A2, A3.
As the pressure gradually rises from cm2, the pointer of the pressure gauge 7 causes micro-vibration in the range shown by the waveform between the rising pressures A1, A2, A3 and the lower limit pressure, indicating that the air amount has decreased. . When the plunger pump P is operated in the state where the rising pressure is A3, the pressure gauge 7 is damaged in a short time, and when the plunger pump P is operated for a long time, the piping is damaged. Therefore, the operation of the plunger pump P is stopped. It is necessary to drain the water, operate the air compressor, and supplement the compressed air into the pressure tank 5 from the valve 10 to adjust the pressure. Therefore, the frequency of operation / stop in the continuous operation is increased, and the water supply efficiency is reduced. Had declined.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional technical problem, and can supply air without stopping the reciprocating pump even if the amount of air in the pressure tank decreases. It is an object of the present invention to provide a piping structure around a reciprocating pump that can be operated continuously.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned technical problems, the present invention provides a pipe line on the downstream side connected to a reciprocating pump for pumping a liquid, which is provided with a pressure close to the reciprocating pump. A tank is provided, and the pressure tank is provided with a pressure gauge with a contact for detecting the pressure of the air chamber and transmitting the pressure to a control device, and an air introduction pipe is provided at least on an upstream side of the reciprocating pump. An on-off valve, which is connected to the control device, opens the air introduction line based on a signal from a pressure gauge with a contact, and introduces air into the line, is connected to the air introduction line. It is a piping structure around a reciprocating pump that is configured to be installed.

[0006]

According to the above construction, the upper limit pressure at which the on-off valve arranged in the air introduction pipe is opened by the pressure gauge with a contact attached to the pressure tank based on the maximum set pressure of the air chamber of the pressure tank. By setting the range, during continuous operation of the reciprocating pump, the decrease in air is detected by the rise in pressure in the air chamber of the pressure tank, and the on-off valve of the air introduction pipe is opened to open the air to the pipe. By introducing the air, the air is sucked into the pipeline together with water by the reciprocating operation of the reciprocating pump, and the air can be easily supplemented into the pressure tank, and the internal pressure of the pressure tank falls within the set pressure. Since it can be stabilized, continuous operation can be stably performed, and the water supply efficiency can be increased, and damage to the pressure gauge, the pipeline, and the like can be prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a reciprocating pump, that is, piping around a plunger pump P. As in the prior art, a suction pipe 2 connected to an upstream water tank 1 is connected to the suction side of the plunger pump P, and a discharge pipe 3 connected to a downstream water supply facility is connected to the discharge side. It is connected. Further, a pressure tank 5 having a predetermined capacity is connected via a branch pipe 4 to a predetermined position close to the plunger pump P in the discharge pipe 3, and the pressure tank 5 has a water surface h at a predetermined water level. The air chamber 6 is formed on the upper surface side. Also,
The pressure tank 5 is provided with a pressure gauge 7 with a contact. The pressure gauge 7 with a contact is relayed to a control device 8, and the control device 8 controls the air in the pressure tank 5 through the pressure gauge 7 with a contact. The pressure in the chamber 6 is detected, and a signal is transmitted to the control device 8.

Further, an air introduction line 15 having an air filter 16 attached to an end thereof is connected to the suction line 2 adjacent to the plunger pump P, and the air introduction line 15 is connected to the air introduction line 15. On-off valve for opening and closing, for example, solenoid valve 17 and check valve 1
The solenoid valve 17 is connected to the control device 8 so that when the pressure in the pressure tank 5 becomes equal to or higher than the set pressure, the solenoid valve 17 is controlled based on the detection signal of the pressure gauge 7 with a contact. Is opened for a predetermined time to supply air to the suction pipe line 2.

In the piping arrangement around the plunger pump P thus arranged, the experimental measurement result of the pressure adjustment accompanying the pressure fluctuation of the air chamber 6 of the pressure tank 5 is shown in FIG.
In this case, as shown in FIG. 1, a measurement pressure setting valve 20 is disposed on the downstream side of the discharge pipe 3 close to the branch pipe 4, as shown in FIG. The plunger pump P is operated with the pressure setting valve 20 closed, thereby setting the maximum set pressure in the air chamber 6 in the pressure tank 5 to, for example, 5 kgf / cm2. Next, while operating the plunger pump P and opening the pressure setting valve 20, the lower limit pressure is, for example, 2 kgf /
Set the valve opening to cm2. In this case, a general liquid column pressure gauge is used as the measurement pressure gauge.
Further, between the maximum pressure and the lower limit pressure, the amplitude of the liquid column pressure gauge in one stroke of the plunger pump P is shown.

With the pressure in the air chamber 6 of the pressure tank 5 set as described above, the plunger pump P is started to operate continuously. The operation elapsed time hr and the measured value of the pressure fluctuation in the pressure tank 5 in the course of this continuous operation are shown in FIG. 2 (B), and the pressure tank 5 is moved between a point in time b1 and a point in time b2. The internal pressure gradually increases from the set pressure of 5 kgf / cm2 and reaches approximately 6 kgf / cm2 at the time of b2, indicating a decrease in the amount of air. Since continuous operation in the state of b2 is a danger area, the solenoid valve 17 of the air introduction pipe 15 is opened at the time of b2 (for example, manual operation).

By opening the electromagnetic valve 17 of the air introduction pipe 15, air is introduced into the suction pipe 2 from the atmosphere through the air filter 16. The air introduced into the suction pipe 2 is sucked together with water in the suction step of the plunger pump P, and is discharged to the discharge pipe 3 in the discharge step. It is introduced into the tank 5. This air is introduced into the pressure tank 5 by opening the solenoid valve 17 for a predetermined time.

At time c1 when the solenoid valve 17 is opened for a predetermined time, air is replenished into the pressure tank 5, and the upper limit of the amplitude of the measuring pressure gauge is obtained at time c1 due to the reciprocating operation of the plunger pump P. The pressure was in the range of about 4.3 kgf / cm2 and the lower limit was in the range of about 2.5 kgf / cm2, which was close to the initially set upper limit pressure of 5 kgf / cm2 and lower limit pressure of 2 kgf / cm2, and the air chamber 6 was filled with air. (The solenoid valve 17 is closed at the time point c1).

When the plunger pump P continues to reach the time point c2 from the time point c1, the internal pressure of the pressure tank 5 reaches approximately 6 kgf / cm2 at the time point b2, and the air volume in the air chamber 6 decreases again. When the solenoid valve 17 is opened in the same manner as described above, air is introduced into the suction pipe 2, and when the plunger pump P is operated, the air is discharged together with water to the discharge pipe 3 side. The air is supplied into the pressure tank 5 in the same manner as described above, and the upper limit pressure of the amplitude of the measurement pressure gauge is approximately 4.5 kgf / cm2 and the lower limit pressure is approximately 2. 5kgf / cm2
Which is close to the initially set upper limit pressure of 5 kgf / cm2 and the lower limit pressure of 2 kgf / cm2, indicating that the air chamber 6 has been filled with air.

As shown by d1 to d2, e1 to e2..., The amount of air is reduced, and at d2, e2. By introducing the air to the side, the air is sucked together with the water in the suction step of the plunger pump P, is discharged to the discharge pipe 3 in the discharge step, and the air is filled in the pressure tank 5.

As described above, based on the actual measurement results, the pressure gauge 7 with a contact attached to the pressure tank 5 in the present embodiment is obtained.
By setting the upper limit pressure range in which the solenoid valve 17 disposed in the air introduction pipe 15 is opened based on the maximum set pressure of the air chamber 6 of the pressure tank 5 as a reference, during continuous operation of the plunger pump P, Detecting a decrease in the air by the pressure increase of the air chamber 6 of the pressure tank 5, opening the solenoid valve 17 of the air introduction line 15 and introducing the air into the suction line 2, the air is plunged. In the suction step of the pump P, it is sucked together with water, and discharged in the discharge pipe 3 in the discharge step. Air can be easily supplemented into the pressure tank 5 so that the internal pressure of the pressure tank 5 falls within the set pressure. Since it can be stabilized, continuous operation can be stably performed, and the water supply efficiency can be increased, and damage to the pressure gauge, the pipeline, and the like can be prevented.

In the above embodiment, the air introduction line 15 is connected to the suction line 2 on the upstream side of the plunger pump P. However, the present invention is not limited to this example.
The air can be introduced into the pressure tank 5 by connecting it to the downstream side of the discharge line 3 as shown by an alternate long and short dash line in FIG. Further, although the water tank 1 is exemplified as being buried in the ground GL, the present invention is not limited to this. The water tank 1 may be provided at a predetermined height position above the ground GL as in a water tank 1A shown by a dashed line in FIG. In this case, it is preferable that the position of the air filter 16 (suction port) in the air introduction pipe is set at a height h1 higher than the water surface of the water tank 1A. It is preferable to make the height higher. In addition, although the introduction of the air has been exemplified as being introduced from the atmosphere, it may be introduced by the air compressor 21 as shown in FIG. 1, and in this case, it is preferable to supply the air at a pressure slightly higher than the atmospheric pressure.

[Brief description of the drawings]

FIG. 1 is a piping diagram around a plunger pump.

FIG. 2 is an actual measurement data diagram of air supplementation accompanying a continuous operation time of a plunger pump and a change in pressure in a pressure tank.

FIG. 3 is a piping diagram around a conventional plunger pump.

[Explanation of symbols]

 2 suction line 3 discharge line 5 pressure tank 6 air chamber 7 pressure gauge with contact 8 control device 15 air introduction line 17 solenoid valve (open / close valve) P plunger pump (reciprocating pump)

Claims (1)

[Claims] 1. A pressure tank is disposed in a downstream pipe line connected to a reciprocating pump for pumping a liquid in proximity to the reciprocating pump. Pressure gauge with a contact that detects
An air introduction pipe is connected to at least an upstream pipe of the reciprocating pump, and the air introduction pipe is connected to the control device and is connected to the control device based on a signal from a pressure gauge with a contact. A piping structure around a reciprocating pump in which an on-off valve for opening the passage and introducing air into the pipeline is provided.