JP2593797Y2 - Liquid ejector unloader - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unloader for a liquid ejecting apparatus.

The liquid ejecting apparatus is used, for example, as a high-pressure washing machine for ejecting high-pressure water to wash various machines and the like, a pesticide spraying machine for spraying pesticide liquids, etc. When the liquid ejecting nozzle of the liquid ejecting apparatus is operated while the liquid ejecting nozzle is closed, the pump is operated with no load to prevent an excessive load from being applied to the pump and the prime mover.

[0003]

2. Description of the Related Art A liquid ejecting apparatus as described above generally includes:
A tank as a water source in which the liquid to be ejected is stored, a pump for sucking the liquid from the tank and pumping the liquid through a liquid pumping line, and provided at the tip of the liquid pumping line to control the liquid injection And an injection nozzle having an open / close valve.

In the above-described liquid ejecting apparatus, there is a problem that if the ejection nozzle opening / closing valve is closed while the pump is operated, an excessive load is applied to the pump and the pump is damaged.

Therefore, conventionally, for example, 3-8
An unloader as described in Japanese Patent No. 6061 is provided.

The conventional unloader comprises a casing having an import for receiving the liquid pumped by the pump and an out port for discharging the liquid flowing from the import, wherein the import comprises the liquid pumping pipe. An upstream side (the pump side) of the passage, and the out port is located downstream of the liquid pressure feed line (the injection nozzle side) in the middle of the pipe of the liquid pressure feed line.

[0007] A check valve is provided in the casing to allow the flow of the liquid from the import to the outport, but to prevent the flow of the liquid in the opposite direction.

The casing is provided with a spill port for returning the liquid flowing from the import to the tank side. Open between the spill port and the import when the pressure in the liquid pumping line on the injection nozzle side becomes a predetermined value or more, and conversely, the pressure in the liquid pumping line on the injection nozzle side Is set to a predetermined value or less, a spill valve that closes is provided.

The conventional unloader constructed as described above operates as follows.

When the injection nozzle opening / closing valve is closed while the pump is operating, the pressure in the liquid pressure feed line rapidly increases. At this time, since the check valve is operating, the liquid does not flow back from the outport side to the import side.

On the other hand, when the pressure in the liquid pressure feed line on the injection nozzle side becomes equal to or higher than a predetermined value, the spill valve is greatly opened, and the liquid flowing from the import flows from the spill port to the tank side. Returned to

As described above, since the liquid to be pumped by the pump circulates without being pumped to the ejection nozzle side, an excessive load is not applied to the pump and the like.

[0013]

However, in the unloader having the conventional structure, the import and the out port are respectively connected in the middle of the liquid pressure feeding line, and the liquid is always pumped through the casing. Since the check valve is configured to prevent the backflow of the liquid in the casing, there is a problem that durability is lacking.

For this reason, for example, there is a drawback that it is not suitable for use in a liquid ejecting apparatus for a large amount of water such as for pumping a liquid of 100 liters or more per minute.

There is also a drawback that the method is not suitable for use with liquids containing sludge and the like.

The present invention has been made in view of the above circumstances, and aims to provide an unloader of a liquid ejecting apparatus which does not require a check valve and is suitable for large water volume and sewage water. is there.

[0017]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a liquid ejecting apparatus comprising a pump for pumping liquid to an ejecting nozzle and an ejecting nozzle opening / closing valve for opening and closing the ejecting nozzle. A valve chamber provided with an import connected in the middle of the pipeline, a return port for returning the liquid flowing from the import to the water source side, and a spill port, and closing the spill port from the inside of the valve chamber. And a valve element that is pushed back against the urging force to open the spill port in response to an increase in the pressure in the valve chamber due to the inflow of liquid from the import, and
An electric valve that opens and closes the return port operates in response to the outflow of liquid having a predetermined spray pressure or higher from the spill port and opens.
And a switch to be operated .

[0018]

In the unloader according to the present invention, the import is connected to a liquid pumping line connecting the pump and the injection nozzle constituting the liquid injection device, and the return port and the spill port are connected to the water source side. It is arranged.

When the pump is operated to open the injection nozzle opening / closing valve, the liquid pumped through the liquid pressure feed pipe is jetted from the injection nozzle at a high speed.

At this time, also in the valve chamber of the unloader,
Liquid flows in from the import connected to the liquid pumping line. However, if the outflow of liquid from the return port of the valve chamber is suppressed by the electric valve,
There is no outflow of liquid from the return port.

On the other hand, the spill port of the valve chamber is closed from the valve chamber side by the valve body, but the valve body is urged in a direction to close the spill port, and the valve chamber is closed. Is opened against the urging force in response to an increase in the pressure of the pressure. When the liquid is being injected from the injection nozzle, since the pressure in the valve chamber is a predetermined spray pressure, the degree of opening of the valve body is small, and the outflow amount of the liquid from the spill port is small. Speed is also small. Therefore, the switch does not operate, the motor-operated valve remains closed, and there is no outflow of liquid from the return port.

The above is the operating state of the unloader during liquid ejection.

Next, when the injection nozzle opening / closing valve is temporarily closed while the pump is operated, the pressure in the liquid pressure feed line rapidly increases. At the same time, the pressure in the valve chamber of the unloader increases.

When the pressure in the valve chamber is equal to or higher than a predetermined pressure, the valve body is pushed back against the urging force to open the spill port greatly, and at a high speed from the spill port. Large liquid spills.

As a result, in response to the outflow of the liquid having a predetermined spray pressure or more , the switch is turned on, for example, to open the electric valve. When the electric valve is opened, the liquid flowing into the valve chamber is returned directly from the return port to the water source side, and low-pressure light-load operation of the pump is achieved.

The above is the operating state of the unloader when the liquid injection is stopped.

Further, when the injection nozzle opening / closing valve is opened again and the injection of the liquid is restarted, the pressure in the valve chamber decreases to a predetermined spray pressure, so that the valve moves in a direction to close the spill port. . Thereby, the outflow of the liquid from the spill port is reduced, the switch is turned off to close the electric valve, and the outflow of the liquid from the return port is stopped.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an unloader 1 of a liquid ejecting apparatus according to an embodiment of the present invention, and FIG.
FIG. 2 is a fluid circuit diagram showing a state in which the unloader 1 shown in FIG.

In FIG. 2, reference numeral 2 denotes a tank as a water source for storing the liquid to be jetted, and reference numeral 3 denotes a plunger type high pressure pump for pumping the liquid sucked from the tank 2 through the suction pipe 4 through the liquid pressure feeding pipe 5. Reference numeral 3a denotes a motor for operating the pump, 6 denotes a liquid ejecting nozzle provided at the tip of the liquid pressure feeding pipe line 5, and 7 denotes a liquid ejecting nozzle provided in the ejecting nozzle 6 and controls ejection of liquid from the ejecting nozzle 6. The injection nozzle on / off valve of a trigger lever type or the like is shown, each having the same configuration as that described in the section of the related art.

Unloader 1 according to the present embodiment shown in FIG.
A return port 10 for returning the liquid flowing from the import 8 to the tank 2 via a return line 9;
The casing 12 includes a spill port 11 connected to the side, and a casing 12 having a valve chamber 13.

In the illustrated example, the import 8 and the return port 10 face each other.

The spill port 11 of the casing 12
A cylindrical valve body support 14 extending toward the spill port 11 is attached to a portion facing the spill port 11 so as to communicate between the inside and the outside of the valve chamber 13. A cylindrical valve body 1 via a sealing ring 15 for prevention
6 are slidably inserted in the axial direction.

The valve element 16 is formed in a tapered shape so that the tip end thereof becomes gradually thinner, and the tip end side forms a ring-shaped valve seat 17 which forms the periphery of the spill port 11.
And maintain the liquid tightness in the valve chamber 13.
The tapered surface 18 on the distal end side of the valve body 16 serves to close the spill port 11 and also acts as a push-back pressure receiving surface for receiving a pressure in a direction to open the spill port 11. It is.

A hollow portion 19 is provided in the valve body 16 and extends from the rear end portion toward the front end side.
Inside, a coil spring 20 for applying a biasing force to the valve body 16 in the direction of the valve seat 17 is inserted. A spring receiver 21 is provided at the rear end of the coil spring 20.

The urging force applied to the valve element 16 by the coil spring 20, that is, the pressing force of the valve element 16 against the valve seat 17 can be appropriately adjusted by a pressure adjusting knob 22 described below. I have.

That is, the pressure adjusting knob 22 includes a grip portion 23 and a small-diameter shaft 24 integrally formed with the grip portion 23 and extending linearly.
Is slidably penetrated into the valve body 16 and is screwed into a substantially cylindrical pressure-control knob receiver 25 attached to the casing 12.

The distal end of the shaft 24 of the pressure adjusting knob 22 projects from the distal end of the valve body 16.
A nut 25 for preventing slipping is screwed into 4a.

A step 26 is provided on the root side of the shaft 24, and the spring receiver 21 is pressed against the step 26.

In the drawing, reference numerals 27 and 28 denote the pressure adjusting knob 2
2 inner peripheral portion of the gripping portion 23 and the pressure adjusting knob receiver 25
29 are threaded threads provided around the outer end of the valve body, and 29 is an air vent hole provided in the pressure-control knob receiver 25 for smooth sliding of the valve element 16. It is.

In the above configuration, when the pressure control knob 22 is screwed into the pressure control knob receiver 25, the spring support 21 is formed by the step 26 of the pressure control knob 22.
Is moved in the direction of the valve element 16. As a result, the coil spring 20 is compressed, and the pressing force of the valve body 16 against the valve seat 17 increases.

Conversely, when the pressure adjusting knob 22 is turned in a direction to come off from the pressure adjusting knob receiver 25, the degree of compression of the coil spring 20 is relaxed, and the pressing force of the valve body 16 against the valve seat 17 is weak. Become.

As described above, the pressing force of the valve body 16 against the valve seat 17 is appropriately adjusted according to a desired spray pressure.

The return port 10 has a joint 30
The return line 9 is connected via a rotary electric valve 31.

The motor-operated valve 31 controls the flow of liquid from inside the valve chamber 13 toward the return line 9. When the motor-operated valve 31 is opened, the valve chamber 13 and the return line 9 are opened. When the motor-operated valve 31 is closed, the communication between the valve chamber 13 and the inside of the return pipe 9 is completely shut off.

The motor-operated valve 31 is electrically connected to a micro switch 32, as described below, and its operation is controlled by the micro switch 32.

The spill port 11 is connected to the return line 9.
Is connected to a bypass pipe 33 connected to the second pipe. A short pipe 3 is provided on the base 33a side of the bypass pipe 33.
4 are inserted perpendicular to the bypass channel 33. The inner end of the pipe 34 is connected to the bypass line 33.
The pitot tube effect is obtained.

In the pipe 34, a step portion serving as a valve seat 35 is provided. On the valve seat 35, a lightweight ball valve 36 is provided.
Is arranged. A shaft 37 is attached to the ball valve 36, and the shaft 37 protrudes outward from an outer end of the pipe 34. The switch button 3 of the micro switch 32 is provided at the tip of the shaft 37.
8 is connected to one end of a switch button pressing plate 39.

The switch button 38 protrudes outward from the switch body 40 in a normal state, and pushes up the switch button pressing plate 39. As a result, the ball valve 36 is in a state of being lifted from the valve seat 35 in the pipe 34 by the protruding output of the switch button 38, and the micro switch 32
Is in the “OFF” state, for example.

With the above configuration, the micro switch 32 is connected to the bypass line 3 from the spill port 11.
It operates in response to the outflow velocity of the liquid in three directions.

That is, when the spill port 11 is opened and a large amount of liquid flows into the bypass pipe 33 at a high speed,
Since the inside of the pipe 34 opened into the bypass pipe 33 is made negative, the ball valve 36 is adsorbed toward the valve seat 35. As a result, the switch button pressing plate 39 presses the switch button 38, and the micro switch 32 is turned on.

Note that reference numerals 41 and 42 in FIG. 1 denote wirings connected to a power supply circuit (not shown).

The unloader 1 according to the present embodiment configured as described above operates as follows.

First, when the pump 3 is operated and the injection nozzle opening / closing valve 7 is opened to start injection of liquid, the liquid sucked up from the tank 2 by the pump 3 passes through the liquid pressure feeding line 5. It is supplied to the injection nozzle 6 and is injected from the injection nozzle 6.

At this time, the valve chamber 1 of the unloader 1
Although the liquid also flows into 3, the pressure in the valve chamber 13 has a value corresponding to a predetermined spray pressure because the injection nozzle on-off valve 7 is open. Accordingly, the valve element 16 is slightly opened by the urging force of the coil spring 20 corresponding to a predetermined remaining water rate. Therefore, the amount of liquid flowing out of the spill port 11 into the bypass pipe 33 is small and low speed, and the negative pressure generated in the pipe 34 is also small, so that the “off” state of the micro switch 32 is maintained. The electric valve 31 is closed.

The urging force applied by the coil spring 20 to the valve body 16 can be freely adjusted by operating the pressure adjusting knob 22 as described above.

Here, when the injection nozzle on / off valve 7 is closed while the pump 3 is operated to temporarily suspend the liquid injection operation, the liquid pressure feeding pipe line 5 whose outlet is closed is successively inserted into the liquid pressure feeding pipe line 5. When the liquid is sent, the pressure in the liquid pressure feeding pipe line 5 rises rapidly.

The pressure in the valve chamber 13 of the unloader 1 sharply rises with the rise of the pressure in the liquid pressure feed pipe line 5. For this reason, a strong push-back pressure is applied to the push-back pressure receiving surface 18 of the valve body 16, and the valve body 16 is pressed against the spill port 1 against the urging force of the coil spring 20.
1 is pushed back so that it opens greatly.

When the spill port 11 is widely opened, the liquid being pumped into the valve chamber 13 is removed from the bypass line 33.
It flows out in large quantities and at high speed. As a result, the negative pressure generated in the pipe 34 inserted into the bypass pipe 33 increases, and the ball valve 36 floating in the pipe 34 is sucked by the protruding output of the switch button 38 so that the valve Adsorbed to the seat 35.

When the ball valve 36 is sucked in the direction of the valve seat 35, the switch button pressing plate 39 presses the switch button 38 of the micro switch 32, and the micro switch 32 is turned on.

As a result, the valve element 31a of the motor-operated valve 31 is rotated by a predetermined angle and opened, and the liquid pumped into the valve chamber 13 by the pump 3 flows out of the return port 10 one after another. It is returned to the tank 2 side.

As a result, even if the pump 3 continues to operate, an increase in the pressure in the liquid pressure feed line 5 can be avoided,
Low pressure operation of the pump 3 is realized.

Next, when the injection nozzle opening / closing valve 7 is opened to restart the interrupted liquid injection operation, the pressure in the valve chamber 13 of the unloader 1 decreases, so that the valve body 1 is opened.
6 moves in the direction to close the spill port 11 by the urging force of the coil spring 20. For this reason, the flow rate of the liquid into the bypass pipe 33 is reduced, and the pipe 3
The negative pressure in 4 is released, the micro switch 32 is turned off, and the electric valve 31 is closed.

The unloader 1 of the liquid ejecting apparatus according to the present embodiment, which operates as described above, is excellent in durability because it is not of the conventional check valve type. Therefore, there is no problem such as damage when applied to a liquid ejecting apparatus for a large amount of water or an ejecting apparatus for polluted liquid.

The unloading pressure can be arbitrarily changed by changing the opening diameter of the electric valve 31.

Further, it is possible to automatically control the stop and operation of the motor 3a for operating the pump 3 by using a signal from the micro switch 32.

[0067]

According to the unloader of the liquid ejecting apparatus according to the present invention, there is no need to use a check valve, the durability is superior to the conventional one, and the liquid ejecting apparatus having a large amount of water and the polluted liquid can be used. There is no problem such as damage even when applied to the injection device of the above.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an unloader of a liquid ejecting apparatus according to an embodiment of the present invention.

FIG. 2 is a fluid circuit diagram showing a state in which the unloader shown in FIG. 1 is connected to a liquid ejecting apparatus.

[Explanation of symbols]

 2 Water source 3 Pump 5 Liquid pressure feed line 6 Injection nozzle 7 Injection nozzle on-off valve 8 Import 10 Return port 11 Spill port 13 Valve room 16 Valve element 31 Electric valve 32 Switch

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F04B 53/00 F04B 23/00 B05B 9/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A liquid pressure feed pipe of a liquid jet apparatus comprising a pump (3) for feeding a liquid to a jet nozzle (6) under pressure and an jet nozzle opening / closing valve (7) for opening and closing the jet nozzle (6). 5) A valve chamber provided with an import (8) connected in the middle of the process, a return port (10) for returning the liquid flowing from the import (8) to the water source (2) side, and a spill port (11). (13) and the spill port (11) from the inside of the valve chamber (13).
And is pushed back against the urging force in response to a rise in the pressure in the valve chamber (13) due to the inflow of liquid from the import (8), and the spill port is A valve element (16) that opens (11) and operates in response to the outflow of liquid having a predetermined spray pressure or more from the spill port (11), and opens the return port (10) .
It switches allowed to electric valve for closing (31) opening operation (3
Unloader of the liquid jet apparatus characterized by including a 2), a.