JP3078952B2 - Method for preventing dripping of liquid from discharge port in liquid pressure feed line - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a one-way valve for preventing backflow at least on a suction side line of a pump, and discharges the liquid in a liquid pressure feeding line for intermittently pumping a predetermined amount of liquid by driving a pump. The present invention relates to a method for preventing dripping of liquid from an outlet.

[0002]

2. Description of the Related Art In the prior art, as schematically shown in FIG. 2, a suction tube 11 made of a synthetic resin hard tube (outer diameter 6 mm, inner diameter 4 mm, minimum bending radius 30 mm).
Is connected to a suction part 21 of a pump 20 which is a reciprocating pump via a joint 13a, and the suction pipe 11 and a suction flow path 23 in the pump 20 form a suction-side pipe line 2 of the pump 20; A discharge pipe 12 made of a hard tube having the same specifications as the suction pipe 11 is connected to a discharge section 22 of the pump 20 by a joint 13b.
The discharge pipe 12 and the discharge flow path 24 in the pump 20 form a discharge side pipe 3 of the pump 20. The suction side pipe 2 and the discharge side pipe 3 form a liquid. A pressure feed line 1 is formed.

A first one-way valve 30a, which is a one-way valve for preventing backflow of the suction-side pipe 2, is provided in the suction channel 23 in the pump 20 in the liquid pressure feeding pipe 1. A second one-way valve 30b, which is a one-way valve for preventing backflow of the discharge-side pipe line 3, is disposed in the discharge passage 24 in the inside. The first one-way valve 30a is composed of a ball valve 31a and the ball valve 31a. A spring 33a for pressing the valve 31a against the valve seat 32a, and a second one-way valve 30b having the same structure as the first one-way valve 30a,
It has a ball valve 31b and a spring 33b for pressing the ball valve 31b against a valve seat 32b.

In FIG. 2, reference numeral 25 denotes a part of the suction and discharge passages 23 and 24 in the pump 20,
Each ball valve 31 of the first and second one-way valves 30a, 30b
3A and 3B show a pump chamber formed by an end face 27 of a piston 26 of the pump 20. A suction pipe 11 is a liquid tank filled with a liquid W as ink from a suction part 21 of the pump 20 (not shown). ), And the liquid pressure feeding pipe line 1 is filled with the liquid W. In this specification,
For one valve element, for example, a one-way valve, the liquid tank side or
The pipeline for pumping the liquid on the pump side is called the downstream pipeline.
The pipeline on the discharge port side from the valve body is referred to as the upstream pipeline.

[0005] In this liquid pressure feed line 1, a pump 20
When the piston 26 moves in the direction A, the pressure in the pump chamber 25 becomes negative, and as a result, this pressure becomes the second one-way valve 30.
b), the ball valve 31b of the second one-way valve 30b is strongly pressed against the valve seat 32b, and the ball valve 31a of the first one-way valve 30a overcomes the pressing force of the spring 33a. The first one-way valve 30a is separated from the valve seat 32a and is in the pressure feeding direction C of the liquid W.
The liquid W in the suction side pipe line 2 on the downstream side is supplied to the first one-way valve 3.
0a, and reaches the inside of the pump chamber 25.

[0006] Thereafter, when the piston 26 of the pump 20 moves in the direction B, the liquid W in the pump chamber 25 is pressurized,
As a result, this pressing force urges the pressing force of the spring 33a of the first one-way valve 30a, and the ball valve 31a of the first one-way valve 30a is strongly pressed against the valve seat 32a, and the second one-way valve 30b is pressed. The ball valve 31b is separated from the valve seat 32b by overcoming the pressing force of the spring 33b, and the liquid W in the pump chamber 25 corresponds to the moving volume of the piston 26 from the stroke end in the direction A to the stroke end in the direction B. The predetermined amount is determined by the second one-way valve 30b and the discharge pipe 12
And the discharge pipe 1 which is the discharge port 4 of the liquid pressure feeding pipeline 1
It is discharged from the second discharge port 4.

For this reason, the pump 20 is driven to drive the pump 2
When the piston 26 is reciprocated, the liquid W in the liquid tank (not shown) moves in the liquid pumping line 1 in the pumping direction C.
And is discharged intermittently by a predetermined amount from the discharge port 4 of the liquid pressure feeding pipe line 1.

However, according to the conventional technique, even if the piston 26 of the pump 20 reaches the stroke end in the direction A and stops moving in the direction A, the liquid W is moved downstream from the first one-way valve 30a in the direction C for feeding the liquid W. The liquid W in the suction-side pipe line 2 keeps flowing according to the law of inertia, and a part of the liquid W flows into the pump chamber 25 through the first one-way valve 30a.

As a result, the pressure of the liquid W in the pump chamber 25 rises, and this increased pressure urges the pressing force of the spring 33a of the first one-way valve 30a, and the first one-way valve 30a
To shut off the flow of the liquid W into the pump chamber 25,
The ball valve 31b of the second one-way valve 30b is replaced with its valve seat 32b.
A part of the liquid W in the pump chamber 25 passes through the second one-way valve 30b and flows into the discharge-side pipe line 3 on the upstream side in the pressure-feeding direction C of the liquid W from the second one-way valve 30b. And
A part of the liquid W in the discharge side pipe 3 is pushed out from the discharge port 4 of the liquid pressure feeding pipe 1, and so-called dropping of the liquid W occurs at the discharge port 4 of the liquid pressure feeding pipe 1.

[0010] Therefore, in the prior art, the liquid pressure feed line 1
Each time a predetermined amount of the liquid W is intermittently fed by using the method, there is a problem that the liquid W drops at the discharge port 4 of the liquid pressure feeding pipe line 1.

In the prior art having this problem, predetermined containers arranged at predetermined intervals are intermittently transported below a discharge port 4 of a liquid pressure feeding pipe 1 and a predetermined amount is transferred to each predetermined container. When the liquid W is injected, the amount of the liquid W injected into each predetermined container fluctuates, and the intermittent transfer device of the predetermined container is contaminated with the liquid W.

In the prior art, in order to shorten the discharge interval of the liquid W intermittently discharged from the discharge port 4 of the liquid pressure feeding pipeline 1, the reciprocating speed of the piston 26 of the pump 20 is increased to increase the unit. When the number of reciprocations of the piston 26 per time is increased, the intermittent operation of the liquid W in the suction side pipe line 2 downstream of the first one-way valve 30a in the pressure feeding direction C of the liquid W increases in proportion to the reciprocating speed of the piston 26. The maximum flow rate during pumping is increased and the kinetic energy during this is increased.

Therefore, according to the law of inertia caused by this kinetic energy, the liquid W in the suction side pipe line 2 downstream of the first one-way valve 30a in the direction C of feeding the liquid W in the pumping direction C is applied to the piston 26 of the pump 20. The amount of the liquid W passing through the first one-way valve 30a after stopping the movement in the direction A increases in proportion to the reciprocating speed of the piston 26. As a result, the dripping of the liquid W from the discharge port 4 in the liquid pressure feeding line 1 is caused. The amount also increased in proportion to the reciprocating speed of the piston 26.

[0014]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, according to the present invention, there is provided a pump in a suction-side pipe downstream of a one-way valve for preventing backflow of a suction-side pipe of a pump in a direction of pumping liquid. Even if the maximum flow rate during the intermittent pumping of the liquid is maximized within an allowable range, it is possible to prevent dripping of the liquid at the intermittent pumping of the liquid from the discharge port in the liquid pumping line. An object of the present invention is to provide a method for preventing dripping of liquid from a discharge port in a road.

[0015]

According to the present invention, a one-way valve for preventing backflow is provided at least on a suction side pipe of a pump, and a liquid is supplied by driving the pump. In a liquid pumping line for intermittently pumping a liquid at a fixed rate, a shut-off valve linked to the pump is disposed in a discharge-side line of the pump, and the shut-off valve is shut off from an open flow path.
Electromagnets, oil
Performed by external driving means selected from pressure, pneumatic, etc.
As a result, the opening and closing of the valve and the flow of
The inertia of the liquid on the flow side, the influence of pressure is shut off, and at the start of intermittent pressure feeding of the liquid to the discharge side pipe by the pump, the discharge side pipe is opened by the shut-off valve, and the liquid is pumped by the pump. When the intermittent pressure feed to the discharge side pipeline is stopped, the discharge side pipeline is shut off by the shutoff valve.

[0016]

According to the present invention employing the above-described structure, the shut-off valve linked to the pump is provided in the discharge side pipe of the pump, and when the pump starts intermittent pressure feeding of the liquid to the discharge side pipe, The discharge side pipe is opened by the shutoff valve, and when the intermittent pressure feeding of the liquid to the discharge side pipe by the pump is stopped, the discharge side pipe is shut off by the shutoff valve. After the one-time intermittent pressure feed is stopped, a part of the liquid on the downstream side of the pump is caused by the flow of the liquid downstream of the one-way valve for preventing the backflow of the suction side pipe of the pump in the pressure direction of the liquid by the law of inertia. Even if the liquid passes through the one-way valve and flows upstream from the one-way valve in the direction in which the liquid is pumped, the liquid is pushed out from the discharge port of the discharge-side pipe of the pump due to the inflow. Is located upstream of the one-way valve in the direction of liquid pressure It is prevented by the blocking of the discharge-side pipe line by shut-off valve which is arranged.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. However, in FIG. 1, the same components and members as those in FIG. 2 are given the same reference numerals as those in FIG. 2, and in the following description, based on FIG. The description of the same parts / members as those already described above will be omitted.

In one embodiment of the present invention, as schematically shown in FIG.
A shutoff valve 150, which is an electromagnetic valve having a flow path, is connected to a discharge portion 22 of the pump 20 which is a reciprocating pump (not shown).
The shut-off valve 150 is connected to the discharge pipe 1 shown in FIG.
A discharge pipe 112 made of a hard tube having the same specification as that of No. 2 (outer diameter 6 mm, inner diameter 4 mm, minimum bending radius 30 mm) is piped through a joint (not shown). Pump 2 with discharge channel 24
A discharge side conduit 103 of zero is formed. In FIG. 1, the shut-off valve 150 is indicated by a piping symbol.

The suction pipe 2 of the pump 20 is connected to the discharge pipe 11
Same specifications as hard tube No. 2 (OD 6mm, ID 4m
m, a minimum bending radius of 30 mm)
The suction pipe 11 is the same as the suction pipe 11 shown in FIG. 2 and a suction flow path 23 in the pump 20. The liquid pressure feeding pipe 100 is connected to the suction side pipe 2 and the discharge side of the pump 20. The pipe 103 is formed. In FIG. 1, reference numeral 104 denotes a discharge port of the discharge side pipe 103 which is a discharge port of the liquid pressure feeding pipe 100.

In the liquid pressure feeding line 100, the pump 20
Suction passage 23 in the pump 20 in the suction side pipeline 2
A first one-way valve 30a, which is a one-way valve for preventing backflow, is disposed in the discharge passage 24 in the pump 20 in the discharge-side conduit 103 of the pump 20 as a one-way valve for backflow prevention. A second one-way valve 30 b is provided, and the liquid W as ink is intermittently pressure-fed by a predetermined amount by driving the pump 20.

In the liquid pressure feeding line 100 described above,
In the illustrated embodiment, the shut-off valve 150 disposed in the discharge-side conduit 103 of the pump 20 is linked to the pump 20, and when the piston 26 of the pump 20 moves in the A direction and reaches the stroke end in the A direction. When the pump 20 starts the intermittent pressure feeding of the liquid W to the discharge side pipeline 103 at a point slightly later, the flow path of the shutoff valve 150 is switched from the shutoff flow path 152 to the open flow path 151, Shut-off valve 150
The discharge side conduit 103 is opened, and the pump 20 at the time when the piston 26 of the pump 20 moves in the direction B from the stroke end in the direction A to reach the stroke end in the direction B slightly, When the intermittent pressure feed of the liquid W to the discharge side pipeline 103 is stopped by the above, the flow path of the shutoff valve 150 is switched from the open flow path 151 to the cutoff flow path 152,
The discharge side pipe line 103 is shut off by the shutoff valve 150.

The liquid pressure feed line 100 shown in FIG.
In the experiment conducted using the conventional technique, the reciprocating speed of the piston 26 of the pump 20 was increased as compared with the conventional technique shown in FIG. 2 to make the liquid W in the pressure feeding direction C downstream of the first one-way valve 30a. Even if the maximum flow velocity during the intermittent pressure feeding of the liquid W in the suction side pipe line 2 is increased, the discharge port of the liquid pumping line 100
It was possible to obtain a good experimental result that the liquid W could be prevented from dropping from the liquid 104 .

In the illustrated embodiment, since the pump 20 is a reciprocating pump, a first one-way valve 30a for preventing backflow is provided in the suction side pipe line 2 of the pump 20, and the pump 20 discharges. A second one-way valve 30b for preventing backflow is provided in the side pipe 103, and a shutoff valve 150 is provided in the discharge-side pipe 103 of the pump 20 in addition to the second one-way valve 30b. The shut-off valve 150 allows the pump 20
When the intermittent pressure feeding of the liquid W to the discharge side pipe 103 by the pump 20 is started, the discharge side pipe 103 is opened, and when the intermittent pressure feeding of the liquid W to the discharge side pipe 103 by the pump 20 is stopped, the discharge side pipe 103 is shut off. Therefore, if the shut-off valve 150 can be used for both positive pressure and negative pressure, even if the pump 20 is a reciprocating pump,
The second one-way valve 30b for preventing backflow in the discharge-side conduit 103 becomes unnecessary.

In the illustrated embodiment, the pump 20 is a reciprocating pump. However, the pump 20 is not limited to a reciprocating pump, but may be a rotary pump such as a gear pump or a screw pump.
A centrifugal pump or an axial pump may be used. However,
In each pump such as a rotary pump, a centrifugal pump, and an axial flow pump, the liquid W is continuously pumped in the liquid pumping line by rotation of an impeller or the like. It is necessary to control ON / OFF of the rotation of the impeller and the like in order to perform the discharge. However, the pump 20 is preferably a reciprocating pump because the reciprocating pump does not need to be controlled.

When the pump 20 is a rotary pump, a centrifugal pump, an axial pump or the like, the one-way valve for preventing backflow only needs to be provided only in the suction side pipe line 2 of the pump 20.

Further, in the illustrated embodiment, the first
And the second one-way valve 30a, 30b is a ball valve 3
1a, 31b, valve seats 32a, 32b, spring 33
a, 33b, but the one-way valve for backflow prevention is not limited to this structure.

Further, in the illustrated embodiment, the shut-off valve 150 is an electromagnetic valve having two flow paths of the open flow path 151 and the cut-off flow path 152. It is not limited to a flow path switching valve such as this electromagnetic valve for switching the passage 152, but may be a gate valve, a ball valve, or the like. The driving method of the shut-off valve 150 is not limited to driving by an electromagnet. Drive by hydraulic pressure, pneumatic pressure or the like may be used.

In the illustrated embodiment, the hard tube forming the suction tube 11 and the hard tube forming the discharge tube 112 have the same specifications, and have an outer diameter of 6 mm.
Although the inner diameter is 4 mm and the minimum bending radius is 30 mm, the hard tube forming the suction tube 11 and the hard tube forming the discharge tube 112 are not limited to the same specification.
Its specifications are 6mm in outer diameter, 4mm in inner diameter, and the minimum bending radius is 30.
It is not limited to mm.

In the illustrated embodiment, the suction pipe 11 and the discharge pipe 112 are hard tubes made of synthetic resin. However, the suction pipe 11 and the discharge pipe 112 are not limited to the hard tubes made of synthetic resin. For example, a pipe made of metal or synthetic resin may be used.

Further, in the illustrated embodiment, the liquid W which is intermittently pumped by the pump 20 in the liquid pumping line 100 by a predetermined amount is ink. However, the liquid W is not limited to ink. -Any liquid such as an organic solvent or solution may be used.

[0031]

According to the present invention having the above-described structure and operation, when the pump stops the intermittent pressure supply of a predetermined amount of liquid to the discharge-side pipe, the backflow in the suction-side pipe of the pump is prevented. To the liquid downstream of the one-way valve
By the flow according to the law of inertia that may arise from, a portion of the liquid on the downstream side through the one-way valve, also flows from the one-way valve in the pumping direction upstream side of the liquid, due to the inflow However, the pushing out of the liquid in the discharge-side pipe, which is a dripping of the liquid, from the discharge port of the discharge-side pipe of the pump, which is the discharge port of the liquid pressure-feeding pipe, causes the one-way valve to pump the liquid in the direction of liquid pumping. it is prevented by the blocking of the discharge-side pipe line by shut-off valve disposed on the upstream side, the maximum during one intermittent pumping of liquid in the one-way valve from the pumping direction downstream side of the liquid suction side conduit even faster to maximize the flow rate within the allowable range, luck
This has the effect of preventing the liquid from dropping at every intermittent pressure feed from the discharge port in the liquid pressure feed line due to the flow due to the increase in kinetic energy .

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing a conventional technique.

[Explanation of symbols]

 2 Pump suction line 20 Pump 30a One-way valve for preventing backflow of suction side line 100 Liquid pumping line 103 Pump discharge side line 104 Discharge port of liquid pumping line 150 Shut-off valve W Liquid

Claims (1)

(57) [Claims] 1. A liquid pressure feeding line having a one-way valve for preventing backflow at least in a suction side line of the pump and intermittently pumping a predetermined amount of liquid by driving the pump, wherein the liquid pressure feeding line is interlocked with the pump. The shut-off valve is disposed in the discharge-side conduit of the pump, and the shut-off valve is opened and closed in the open flow path and the cut-off flow path.
The flow of the liquid is selected from among electromagnet, hydraulic, pneumatic, etc.
By the external drive means, the opening and closing of the valve and the fluid flow
The inertia of the liquid and the influence of the pressure are shut off, and when the pump starts intermittent pressure feeding of the liquid to the discharge-side pipe, the cut-off valve opens the discharge-side pipe, and the pump discharges the liquid on the discharge side. A method for preventing dripping of liquid from a discharge port in a liquid pressure feeding line, wherein the shutoff valve shuts off the discharge side line when intermittent pressure feeding to the line is stopped.