JPS588951Y2 - pump equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pump device, in which a flexible membrane such as a diaphragm membrane is reciprocatingly displaced to pump a spray gun, and when the pump discharge pressure increases beyond a set pressure, the combustible membrane is It is configured to stop the displacement transmission from the drive mechanism, thereby stopping the actual pump action while continuing its operation without imposing a high load on the drive mechanism, and reliably preventing an increase in pump discharge pressure. The purpose of this invention is to provide a pump device with a

In general, various types of fixed volume pump devices, such as a piston-cylinder type and a diaphragm type, are known for pumping a spray liquid under pressure through a spray gun.

This type of fixed displacement pump device always pumps a constant volume of fluid as a spray liquid regardless of the size of the load, so the pump discharge pressure should not exceed a certain value when the load becomes large. A pump discharge pressure control mechanism is provided to control the pump discharge pressure.

However, when the pump discharge pressure increases with an increase in load, the discharge pressure control mechanism of the conventional diaphragm pump device recirculates (reliefs) a portion of the discharge fluid to the low-pressure pump suction side to reduce the pump discharge pressure. The configuration is such that it is prevented from increasing beyond a certain value.

For this reason, even if the pump discharge pressure control mechanism is activated and the pressure increase of the discharge fluid can be prevented, the drive mechanism of the pump device body remains under a high load, and if this condition continues for a long time, Not only does the drive mechanism unnecessarily waste power, but the power transmission mechanism is overworked, which accelerates its wear and tear.

Furthermore, in this device, a portion of the discharged fluid is returned to the low-pressure suction side of the pump, so the temperature of the returned fluid becomes high and its viscosity becomes low, causing problems such as leakage from the seal portion.

Also, a diaphragm type pump device is known which has a configuration in which a rond etc. directly connected to the diaphragm membrane is directly reciprocated and driven, but in this device, when the pump discharge pressure increases, the pressure of the fluid to be pressurized acts on the diaphragm membrane, As a result, the diaphragm membrane has the disadvantage of being damaged in a short period of time.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

The figure shows a schematic vertical sectional view of an embodiment of the pump device according to the present invention.

In the figure, a pump device 1 has a pump device main body 4 provided between a paint can 2 and a spray gun 3, and when the pump device main body 4 is driven once by power from an electric motor (not shown), The paint 2a as a spray liquid in the paint can 2 is sucked into the pump device main body 4 through the suction pipe 5, pressurized there, and fed under pressure to the spray gun 3 through the discharge pipe 6.

7 is a drive shaft connected to the rotating shaft (not shown) of the electric motor, and an eccentric shaft 7a formed at the tip thereof has a bearing γ.
b is fitted.

Reference numeral 8 denotes a drive mechanism including the drive shaft 7, an eccentric shaft 7a, a bearing 7b, a bushing 9 and a piston 10, which will be described later.This will be explained below.

When the electric motor is started and the eccentric shaft 7a rotates, the bushing 9 whose tip abuts against the outer peripheral surface of the bearing 7b is reciprocated at a predetermined period in the vertical direction in the figure.

This bushing 9 springs into the recess 10a of the piston 10.
The piston 10 is fitted so as to be slidable over a predetermined distance by inserting the spring 1a, and therefore, each time the bushing 9 moves downward, the piston 10 receives a downward force commensurate with the amount of compression of the spring lla.

Further, a spring is inserted around the outer circumference of the piston 10 to urge the piston 10 upwardly, and with these configurations, the piston 10 is moved by the spring 11 when the pusher 9 moves downward.
a.

11b in the downward direction in the figure, while the pusher 9
When it is displaced upwardly, it is returned upwardly due to the elastic force of the spring 11b.

The lower end surface of the piston 10 faces a drive-side pressurizing chamber 13 defined by a diaphragm membrane 12, and inside this pressurizing chamber 13 there is oil 14 as a displacement transmitting fluid.
etc. is filled with an incompressible fluid.

Therefore, when the piston 10 is displaced in the vertical direction, the displacement of the piston 10 is transmitted to the diaphragm 11 through the oil 14.
2c is transmitted, and the diaphragm membrane 12 is reciprocated in the vertical direction in synchronization with the displacement of the piston 10.

Here, the oil 14 as the displacement transmission fluid is the oil 14 in the oil reservoir 15 formed in the upper part of the pump device main body 4, which flows into the pressurizing chamber 13 via a communication channel 20, which will be described later. be.

Since the pressurizing chamber 13 is always in a state of no communication with the oil reservoir 15 (when the unload valve drive mechanism described later is not in operation), the oil 14 flows between the lower end surface of the piston 10 and the upper surface of the diaphragm membrane 12. The displacement of the piston 10 is reliably transmitted to the diaphragm membrane 12 via the oil 14, which is an incompressible fluid.

On the other hand, the lower surface of the diaphragm membrane 12 faces into the pressurized chamber 18 on the driven side defined between the suction valve 16 and the discharge valve 17, and is in contact with the paint 2a.

Therefore, when the diaphragm membrane 12 moves upward in accordance with the upward displacement of the piston 10, the pressurized pressure chamber 1
When the paint 2a is sucked into the pressurized chamber 18 and the diaphragm membrane 12 moves downward with the downward displacement l of the piston 10, the paint 2a sucked into the pressurized chamber 18 is discharged into the discharge pipe 6 via the discharge valve 17. It is discharged.

Here, the oil 1 acting on the upper surface of the diaphragm membrane 12
The pressure of 4 and the paint 2 acting on the lower surface of the diaphragm membrane 12
The pressures at a are approximately equal, so that no significant bias pressure is exerted on the diaphragm membrane, unlike in pump devices that use a diaphragm membrane that is in contact with liquid on only one side.

Reference numeral 19 denotes an unload valve having a communication flow path 20+l for communicating the pressurizing chamber 13 on the driving side and the oil reservoir 15. Normally, the ball 21 serving as the valve body is energized to close the valve seat. 23, so that the unload valve 19 is in a closed state.

24 is a discharge pressure detection mechanism, which is connected to the discharge valve 1 through a flow path 25.
A piston 27 as a displacement member is fitted in a paint introduction chamber 26 communicating with the downstream side of the piston 7, and the displacement of the piston 27 is detected as the displacement of the piston rod 27a.

Reference numeral 28 denotes an unloading valve drive mechanism, which brings the tip of the piston rod 27a into contact with one arm 29a of a rotary lever 29, which is provided on the bottom of the oil reservoir 15 so as to be rotatable within a predetermined angle range. The other arm 29b
The rod 30 attached to the unloading valve 19 is extended over the ball 21 of the unloading valve 19, and the tip of the rod 30 moves the ball 21 against the valve seat 23 according to the rotational position of the rotational lever 29. The configuration is as follows.

The rod 30 may be pivotally attached to the arm 29b or fixed to the ball 21, and the collar may simply be inserted between the rod 30 and the arm 29b.

Note that 27b is a stopper attached to the lower surface of the paint introduction chamber 26.

Reference numeral 31 denotes a rod that is brought into contact with one arm 29al of the lever 29 from the opposite side to the piston rod 27a, and a spring 33 fitted between the flange 31a and the lower end of the set pressure adjustment screw 32 causes the rod to move downward in the figure. is assisted by.

The set pressure adjustment screw 32 is used to set the pressure at which the unload valve 1 drive mechanism 28 should be operated, and if the screw-in amount is set as a dog, the elastic force of the spring 33 increases accordingly, so the set pressure is set as a dog. On the other hand, set pressure adjustment screw 32
When the amount of screwing in is made small, the elastic force of the spring 33 decreases,
The set pressure is small.

Assume that, for example, the nozzle of the spray gun 3 is fully closed while the pump device main body 4 is being operated with the screwing amount of the set pressure adjustment screw 32 set to a desired value.

When the spray gun 3 is fully closed, the pump device main body 4 enters the closed operation state, so that the pump discharge pressure increases beyond the set pressure, and the paint 2 introduced into the paint introduction chamber 26 increases.
The pressure at a also increases.

As a result, the piston 27 of the discharge pressure detection mechanism 24 is displaced upward against the urging force of the spring 33 via the rod 31.
Rotate the lever 29 clockwise in the figure.

As the rod 30 is moved downward as the lever 29 is rotated, the ball 21 of the unload valve 19 is pushed by the rod 30 and separated from the valve seat 23 against the force of the spring 22.

As a result, the drive-side pressurizing chamber 13, which had been sealed between the lower end surface of the piston 10 and the upper surface of the diaphragm membrane 12 and was cut off from the oil reservoir 15, is now closed to the unload valve 1.
9 to a low pressure oil reservoir 15.

Therefore, even if the piston 10 reciprocates, the oil 14 in the drive side pressurizing chamber 13 only flows reciprocally between the pressurizing chamber 13 and the oil reservoir 15, and the displacement of the piston 10 is caused by the diaphragm membrane 12. is not transmitted, and the pumping action is substantially stopped.

In this way, when the paint discharge pressure increases due to the nozzle of the spray gun 3 being closed, the discharge pressure detection mechanism 24,
The unload valve drive mechanism 28 and the like operate, and the pumping action of the pump device 1 is substantially stopped.

In that case, the pump device 1 is different from conventional pump devices configured to recirculate (relieve) the discharged paint to the low pressure side, and the pump device 1 stops the displacement transmission from the piston 10 to the diaphragm membrane 12, thereby substantially stopping the pumping action. Since the structure is such that the piston 10, the bearing 7b, and the eccentric shaft 7a
, shaft 7, etc., and the electric motor as a drive source are not subject to a high load.

Therefore, according to the pump device 1, when the unload valve 7 drive mechanism 28 is activated, the pump device main body 4 continues to be operated with no load, so that the electric motor wastes power, and the oil 14 and paint It is possible to reliably prevent inconveniences such as the drive mechanism 2a being overheated unnecessarily or stress being applied to each component of the drive mechanism and shortening its lifespan.

Furthermore, if the pump device 1j is 1L, there is no occurrence of erosion caused by the return of high-pressure fluid, which is seen in the conventional pump device.

As mentioned above, when a nozzle that has been closed is opened again,
Since the discharge pressure of the paint 2a decreases below the set pressure, the discharge pressure detection mechanism 24 and the piston 27 also return downward to their normal positions, and at the same time, the lever 29 also rotates counterclockwise in the figure.

As a result, the rod 30 that was in contact with the ball 21 Ic of the unload valve 19 changes upward and returns, and the ball 21 is urged by the spring 22 and seats on the valve seat 23, causing the unload valve 1
9 is closed.

As a result, the pressurizing chamber 13 on the drive side is cut off from the oil reservoir 15, and the pump device 1 resumes normal pumping action.

In the above explanation, the case where the pump discharge pressure rises above the set pressure due to the spray gun 3 being fully closed has been explained, but this is not limited to the case where the pump discharge pressure rises above the set pressure due to the nozzle of the spray gun 3 being extremely narrowed. Even if the set pressure is exceeded, the discharge pressure detection mechanism 24, unload valve drive mechanism 28, etc. operate in the same manner.

As mentioned above, when the nozzle of the spray gun according to the present invention is closed or throttled and the pressure of the fluid to be pressurized as a spray liquid in the pump device body exceeds the set pressure, the displacement member is displaced. The unload valve drive mechanism is actuated, and the chamber that seals the displacement transmission fluid is communicated with the outside via the unload valve, so that the reciprocating displacement of the drive mechanism via the displacement transmission fluid is not transmitted to the flexible membrane, and the pump device The pumping action of the main body is substantially stopped, thereby reliably preventing the discharge pressure of the pressurized body from increasing excessively beyond the set pressure, and furthermore, the discharge pressure control mechanism controls the pressure of the pressurized fluid. Instead of refluxing the fluid to the low pressure side, it is configured to disable displacement transmission by the displacement transmission fluid interposed between the drive mechanism and the flexible membrane, so that it is not possible to transmit the displacement by the displacement transmission fluid interposed between the drive mechanism and the flexible membrane. A high load may be applied to the pump drive electric motor, wasting power needlessly, causing the displacement transmission fluid to abnormally overheat, or causing the flexible membrane to wear out in a short period of time. It has the advantage of being able to reliably prevent inconveniences.

[Brief explanation of drawings]

The figure is a schematic vertical sectional view of an embodiment of the pump device according to the present invention. 1... Pump device, 4... Pump device main body, 7b.
... Bearing, 8... Drive mechanism, 10... Piston, 12... Diaphragm membrane, 13... Pressure chamber on drive side, 14... Oil, 18... Pressure on driven side Pressure chamber, 19... Unload valve, 24... Discharge pressure detection mechanism, 27... Piston, 28... Unload valve drive mechanism.

Claims (1)

[Scope of utility model registration request] The pump device is provided in contact with the spray liquid between the main body of the pump device, which has a flow path for pumping the spray liquid, and the flow path is provided with a suction valve and a discharge valve, and the suction valve and the discharge valve of the flow path. , a flexible membrane that pressurizes the spray liquid by its reciprocating displacement; a pressurizing chamber defined by the flexible membrane and containing a displacement transmitting fluid therein; a drive mechanism that reciprocates the membrane; a displacement member that detects and displaces when the nozzle of the spray gun is closed or throttled and the discharge pressure in the flow path reaches a set pressure; A pump device comprising: an unload valve that is closed and is provided in the pressurizing chamber and opens in conjunction with the displacement member to release displacement transmission fluid in the pressurizing chamber.