JPS6233111Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid supply device that supplies liquid from a liquid container to a high place using a reciprocating pump, and that prevents backflow of the liquid when the pump is stopped.

The chemical injection unit, which injects chemical liquids such as can cleaning agent into boiler pipes and sodium hypochlorite into water pipes, is connected to chemical liquid tank B containing chemical liquid A, as shown in Figure 1.
A reciprocating pump P is provided above, a suction pipe C is inserted into a chemical solution A in a liquid tank B, and a discharge pipe D is raised upward to form a boiler pipe F.
The reciprocating pump P is driven to suck in the chemical solution A from the suction pipe C and supply it to the boiler piping E etc. via the discharge pipe D.

Therefore, this chemical liquid unit is a reciprocating pump P.
When the drive of the chemical solution A is stopped and the supply of chemical solution A is stopped,
In order to prevent the chemical solution A from descending from the upper discharge pipe D through the pump chamber of the reciprocating pump P in the suction pipe C to the same position as the chemical solution level in the chemical solution tank B and flowing backward, the suction pipe is A check valve (foot valve) F is provided at the lower end opening of C. In other words, when the chemical solution A flows back and the pump chamber of the reciprocating pump P becomes empty, if this condition continues for a long time, the ball-shaped check valves installed at the suction and discharge ports of the pump chamber may become empty. The sealing surface (valve seat surface) becomes dry. Therefore, when the reciprocating pump P is started, the self-priming action is not performed, and the chemical solution A cannot be sucked from the suction pipe C, so that the pump cannot be driven.

However, a check valve (foot valve) F for backflow prevention is provided in the suction pipe to prevent the chemical solution A from flowing downward and backward from the discharge pipe D, but in the check valve F, the valve body and valve seat are Since the seal between them is not sufficient, the chemical solution A in the suction pipe C leaks into the liquid tank B from the gap between the two, and over a long period of time, the chemical solution A in the discharge pipe D leaks into the pump chamber. The liquid flows back through the suction pipe C to the liquid tank B, causing a problem in starting the reciprocating pump P as described above.

The present invention was developed in view of the above circumstances, and when the reciprocating pump is stopped, the improved discharge pipe can reliably prevent liquid backflow without using a check valve, making it easier to operate the reciprocating pump. Moreover, the present invention provides a liquid supply device that can be operated reliably.

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

FIG. 2 shows a chemical solution injection unit to which the device of the present invention is applied, and this chemical solution injection unit is, for example, a device that injects a chemical solution into a pipe connected to a boiler and through which tap water flows. In the figure, reference numeral 1 denotes a chemical solution tank for storing a chemical solution 20, such as a boiler cleaning agent, and a supply port 2 for supplying the chemical solution, which is covered with a lid 3, is provided at the top of the tank 1. In the figure, reference numeral 4 denotes a reciprocating pump installed on the head of the liquid tank 1, and this pump 4 consists of a pump section 5 and a drive mechanism section 6. The pump section 5 includes a pump chamber 7, a ball-shaped check valve 8 provided at the suction port (lower side) of the pump chamber 7, and a pump chamber 7.
For example, a ball-shaped check valve 9 is provided at the discharge port (upper side) of the pump chamber 7, and a plunger 10 that reciprocates within the pump chamber 7 to suck in and discharge the chemical solution 20 is provided. The drive mechanism section 6 uses, for example, a solenoid,
The plunger 10 of the pump section 5 is reciprocated by electromagnetic force. A suction pipe 11 is provided at the suction port of the pump section 5.
However, a discharge pipe 12 is connected to each discharge port,
These tubes 11 and 12 are provided in the chemical tank 1 together with a protective tube 13. The protection tube 13 is fitted into the hole 1a formed in the head of the chemical solution tank 1, and the tank 1 is closed.
It is hung inside. The suction pipe 11 is provided in the protection tube 13 along the vertical direction, and its upper end passes through the closed upper end of the protection tube 13 and is attached to the suction port of the pump part 5 of the reciprocating pump 4 with a nut 14. The lower end (suction port) protrudes from the lower end opening of the protective cylinder 13 and is located at a predetermined height near the bottom of the chemical tank 1, and a strainer 15 is attached thereto. Further, the discharge pipe 12 is formed with a rising portion 12a that rises from the pump 4 on the side connected to the reciprocating pump 4, and on the side connected to the pipe, the minimum allowable liquid level of the chemical solution 20 stored in the chemical solution tank 1 is formed. A depressed portion 12b is formed which extends down to about 100 degrees or below. That is,
One end of the discharge pipe 12 is connected to the discharge port of the pump section 5 by a nut 14 above the chemical tank 1, and after rising upward from this one end, it bends horizontally and then bends downward again. As a result, a rising portion 12a is formed, and furthermore, a rising portion 1
The downwardly bent portion of 2a extends, passes through the upper end of the protective tube 13, descends vertically inside the tube, and bends upward at the same height as the lower end of the suction pipe 11 (pump side portion 12c); A depressed portion 12b is formed by vertically moving up inside the protection tube 13 again and attaching the other end to the upper end of the protection tube 13 with the nut 14 (piping side portion 12d). Note that, for example, the bottom part of the depressed part 12b is the part where the chemical liquid 2 enters the chemical liquid tank 1.
It is located at the same position as or below the lowest allowable level of the chemical liquid 20 when replenishing the chemical liquid 20. The depressed portion 12b has a box-shaped shape such that the pump side portion 12c descends from the rising portion 12a to the lowest position, and the wiring side portion 12d rises again to the piping side end. moreover,
An injection pipe 16 is connected to the other end of the discharge pipe 12,
This injection pipe 16 is connected to piping 17 of the boiler. Note that the boiler piping 17 is connected to the reciprocating pump 4.
It is located higher up and has a higher lifting height. In addition, in the figure, 18 is a strainer provided at the inlet 2 of the chemical liquid tank 1, and 19 is a drain port provided at the lower part of the peripheral wall of the chemical liquid tank 1.

Thus, the chemical liquid 20 is supplied into the chemical liquid tank 1 from the inlet port 2, and is stored so that the level of the chemical liquid 20 reaches near the top of the tank 1. Reciprocating pump 4
The solenoid of the drive mechanism section 6 causes the plunger 10 of the pump section 5 to reciprocate, thereby sucking in and discharging the chemical solution. By driving the reciprocating pump 4, the chemical liquid 20 in the chemical liquid tank 1 enters the pipe from the lower end opening of the suction pipe 11 via the strainer 15, passes through the suction pipe 11, and passes through the check valve 8 on the suction port side of the pump section 5. and reaches the pump chamber 7. In the pump chamber 7, the plunger 10 pressurizes the chemical liquid 20, and the pressurized chemical liquid 20 is discharged into the discharge pipe 12 via the discharge port side check valve 9. The chemical solution 20 in the discharge pipe 12 is in the rising part 1
2a, and then descends through the pump-side portion 12c, which is one of the pipes of the drop-in portion 12b, and reaches the bottom, then rises through the other pipe, the pipe-side portion 12d, and enters the injection pipe 16. Next, the chemical solution 20 is injected into the boiler piping 17 through the injection pipe 16, and
Also, remove deposits inside the boiler and clean it. In this way, as the reciprocating pump 4 supplies the chemical 20 in the chemical tank 1 to the boiler piping 17, the amount of the chemical 20 in the chemical tank 1 decreases, the liquid level drops, and the chemical needs to be replenished. In this embodiment, it is possible to transfer the chemical solution 20 until the liquid level drops to the lower end opening of the suction pipe 11, but in order to prevent the chemical solution from rising, the chemical solution 20 can be transferred before the liquid level drops to the lower end opening of the suction pipe 11. The chemical solution 20 is replenished at a liquid level above that level.

When the chemical solution 20 is not injected into the boiler piping 17, the drive of the reciprocating pump 4 is stopped and the chemical solution 20 in the chemical solution tank 1 is injected into the boiler piping 17.
Stop supplying work to. Then, the chemical liquid 20 that has been sent into the injection pipe 16 flows down into the pipe side pipe portion 12d of the depressed part 12b in the discharge pipe 12, and the liquid level O of the chemical liquid 20 in the chemical liquid tank 1 when the chemical liquid transfer is stopped is changed. Descend to the same position. That is, the liquid level O' in the high side pipe portion 12d and the liquid level O in the chemical liquid tank 1 are at the same height. Therefore, the chemical liquid 20 is transferred from the liquid level of the discharge pipe 12 to the chemical liquid tank 1, that is, from the liquid level of the discharge pipe 12.
2, a pipe side portion 12d of the depressed portion 12b,
Pump side portion 12c and rising portion 12a
It exists between the pump chamber 9 of the pump section 5 of the reciprocating pump 4 and the suction pipe 11.
The liquid level in the piping side portion 12d is determined according to the liquid level in the chemical liquid tank 1, but the chemical liquid 20 is always present from the liquid level in the piping side portion 12d until it reaches the chemical liquid tank 1. . However, when the tank 20 in the chemical solution tank 1 is reduced below the lower end port of the suction pipe 11, the depressed portion 1 in the discharge pipe 12
Although the chemical liquid 20 remains only at the bottom of the tank 2b and does not remain in the rising part 12a of the discharge pipe 12, the pump part 5 of the reciprocating pump 4, or the suction pipe 11, This situation can be prevented by setting the liquid level below the allowable liquid level, that is, the liquid level at which chemical liquid replenishment is performed. Therefore, even if the reciprocating pump 4 is stopped for one day and the chemical solution 20 is not transferred, the pump chamber 7 of the pump section 5 and the check valves 8, 9
The chemical solution 20 is always present. Therefore, when starting the reciprocating pump 4 again, the self-priming effect at the time of starting can be performed well and the chemical solution 20 can be easily sucked from the suction pipe 11, and the reciprocating pump 4 can be started easily and reliably. I can do it.

In addition, in the liquid supply device of the present invention, a reciprocating pump is installed at a height above the highest liquid level of the liquid to be transferred, and the liquid is supplied to a location further above. Basically, it has a U-shaped depression that drops below the lowest allowable liquid level. For example, the minimum allowable liquid level is mainly the liquid level for replenishing the liquid. The liquid container is not limited to a tank, but may be of other types. The drop portion of the discharge pipe may be provided outside the liquid container. The reciprocating pump may use a mechanical drive mechanism such as a crank. In addition, it can be used in a wide variety of applications other than chemical injection units.

As explained above, the liquid supply device of the present invention has the following features:
When the reciprocating pump is stopped and the liquid supply is stopped, the liquid in the discharge pipe drops to the same level as the liquid in the liquid container at the falling part and stops. Since liquid is always present in the pump chamber, when starting the reciprocating pump, self-priming can be performed well and the reciprocating pump can be started easily. Further, there is no need to provide a check valve in the suction pipe as in the conventional case.

[Brief explanation of the drawing]

FIG. 1 is a pipeline diagram showing a conventional device, and FIG. 2 is a schematic sectional view showing an embodiment of the device of the present invention. DESCRIPTION OF SYMBOLS 1... Chemical liquid tank (liquid container), 2... Inlet port, 4... Reciprocating pump, 5... Pump section, 6...
... Drive mechanism section, 11 ... Suction pipe, 12 ... Discharge pipe, 12a ... Rising part, 12b ... Falling part, 17 ... Boiler piping, 20 ... Chemical solution.

Claims (1)

[Scope of utility model registration request] a liquid container; a reciprocating pump installed at a height higher than the highest liquid level of the liquid contained in the liquid container; and a discharge pipe connected to the reciprocating pump to supply the sucked liquid to a higher place than the reciprocating pump, the discharge pipe having a U-shaped depression and The drop portion extends downward to approximately the same height as the opening of the lower end of the suction pipe, and is located below the lowest allowable liquid level of the liquid in the liquid container.