JPH06300200A - Method for preventing drooling of liquid through delivery port of liquid forced feed pipe line - Google Patents

Abstract

PURPOSE:To reduce the occurrence of drooling of liquid to the delivery port of a liquid forced feed line each time liquid is intermittently fed with a pressure, in the liquid forced feed line which is provided with a one-way valve for preventing the occurrence of a reverse flow located in the line on the suction side of at least a pump and through which liquid is fed with a pressure in given quantities through drive of a pump. CONSTITUTION:A soft tube 115 made of synthetic resin is used in a line 102 on the suction side located downstream of the forced feed direction C of liquid W from a one-way valve 30 for preventing the occurrence of a reverse flow of a line 102 on the suction side. When, through running of a pump 20, the liquid W is sucked toward the pump 20, the soft tube 115 is contracted by means of a negative pressure generated in the line 102 on the suction side. Further, when a negative pressure during one full intermittent forced feed of the liquid W in the soft tube 115 is decreased from a maximum negative pressure, a contraction amount of the soft tube 115 is reduced from a contraction amount at a maximum negative pressure period and the flow passage section area of the soft tube 115 is increased to a value higher than a flow passage section area at a maximum negative pressure period.

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 in at least a suction side pipe line of a pump, and discharges a predetermined amount of liquid intermittently by driving the pump. The present invention relates to a method for preventing liquid from dripping from an outlet.

[0002]

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

A first one-way valve 30a, which is a one-way valve for preventing backflow of the suction side pipe line 2, is arranged in the suction flow passage 23 in the pump 20 of the liquid pressure feed pipe line 1, and the pump 20 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 flow path 24 therein, and the first one-way valve 30a includes a ball valve 31a and a ball valve 31a. The second one-way valve 30b having the spring 33a for pressing the valve 31a against the valve seat 32a and having the same structure as the first one-way valve 30a is
It has a ball valve 31b and a spring 33b for pressing the ball valve 31b against the valve seat 32b.

In FIG. 2, reference numeral 25 is 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
3 shows a pump chamber formed by a and 31b and an end surface 27 of the piston 26 of the pump 20, and the suction pipe 11 is a liquid tank (not shown) filled with the liquid W which is ink from the suction portion 21 of the pump 20. ), And the liquid pumping line 1 is filled with the liquid W.

In this liquid pressure-feeding pipeline 1, a pump 20
When the piston 26 moves in the direction A, the inside of the pump chamber 25 becomes a negative pressure, and as a result, this pressure is applied to 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 pressure of the spring 33a. The first one-way valve 30a in the pumping direction C of the liquid W separated from the valve seat 32a
The liquid W in the suction side pipeline 2 on the further downstream side is the first one-way valve 3
It passes through 0a and reaches the inside of the pump chamber 25.

Thereafter, when the piston 26 of the pump 20 moves in the B direction, 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, the ball valve 31a of the first one-way valve 30a is strongly pressed against the valve seat 32a, and the ball valve 31a of the second one-way valve 30b. The ball valve 31b overcomes the pressing force of the spring 33b and is separated from the valve seat 32b, and the liquid W in the pump chamber 25 corresponds to the moving volume of the piston 26 from the stroke end in the A direction to the stroke end in the B direction. The predetermined amount to be set is the second one-way valve 30b and the discharge pipe 12
The discharge pipe 1 which is the discharge port 4 of the liquid pressure-feeding pipeline 1.
It is discharged from the two discharge ports 4.

Therefore, the pump 20 is driven to drive the pump 2
When the piston 26 of No. 0 is reciprocated, the liquid W in the liquid tank (not shown) moves in the liquid pumping line 1 in the pumping direction C thereof.
And is intermittently discharged from the discharge port 4 of the liquid pressure-feeding conduit 1 by a predetermined amount.

However, in the prior art, even if the piston 26 of the pump 20 reaches the stroke end in the A direction and stops moving in the A direction, it is downstream of the first one-way valve 30a in the C direction in which the liquid W is pumped. Since the flow of the liquid W in the suction side conduit 2 is maintained according to the law of inertia, a part of the liquid W passes through the first one-way valve 30a and flows into the pump chamber 25.

As a result, the pressure of the liquid W in the pump chamber 25 rises, and this rising pressure urges the pressing force of the spring 33a of the first one-way valve 30a to cause the first one-way valve 30a.
To block the flow of the liquid W into the pump chamber 25,
The ball valve 31b of the second one-way valve 30b is attached to its valve seat 32b.
Part of the liquid W in the pump chamber 25 passes through the second one-way valve 30b and flows into the discharge-side conduit 3 upstream of the second one-way valve 30b in the pumping direction C of the liquid W in order to separate the liquid W from the second one-way valve 30b. Then
A part of the liquid W in the discharge side pipe line 3 flows out from the discharge port 4 of the liquid pressure feed pipe line 1, and so-called dripping of the liquid W occurs at the discharge port 4 of the liquid pressure feed pipe line 1.

Therefore, in the prior art, the liquid pressure feeding line 1
There is a problem that every time a predetermined amount of liquid W is intermittently pressure-fed using, the liquid W is dripping at the discharge port 4 of the liquid pressure-feeding conduit 1.

In the prior art having this problem, the predetermined containers arranged at a predetermined interval are intermittently transferred below the discharge port 4 of the liquid pressure-feeding pipeline 1 to a predetermined amount in each predetermined container. When the liquid W is injected into each predetermined container,
The injection amount of the liquid fluctuated, and the intermittent transfer device of the predetermined container was contaminated with the liquid W.

[0012]

In view of the above-mentioned problems of the prior art, in the present invention, each time a predetermined amount of liquid is intermittently pressure-fed using the liquid pressure-feeding conduit, it is generated at the discharge port of the liquid pressure-feeding conduit. It is an object of the present invention to provide a method for preventing liquid dripping from a discharge port in a liquid pressure-feeding conduit, which can reduce liquid dripping compared to the conventional technique shown in FIG.

[0013]

As means for solving the above-mentioned problems, in the present invention, a backflow preventing one-way valve is provided in at least a suction side pipe line of a pump, and liquid is stored by driving the pump. In a liquid pumping line that intermittently pressurizes quantitatively, a soft tube made of synthetic resin is used for the suction side line downstream of the one-way valve in the pumping direction of the liquid, and the liquid is driven by the pump. The soft tube is contracted by the negative pressure generated in the suction side pipe line when sucking toward the pump, and the negative pressure during the intermittent intermittent feeding of the liquid in the soft tube is from the maximum negative pressure during that period. When decreasing, the shrinkage amount of the soft tube is reduced from the shrinkage amount at the maximum negative pressure, and the flow passage cross-sectional area of the soft tube is increased from the flow passage cross-sectional area at the maximum negative pressure. It has adopted the configuration.

[0014]

In the present invention having the above-mentioned structure, a soft tube is used on the downstream side of the one-way valve for backflow prevention in the suction side conduit of the pump in the pumping direction of the liquid. When the negative pressure during one intermittent pumping decreases from the maximum negative pressure during that period, to increase the flow passage cross-sectional area of the soft tube from the flow passage cross-sectional area at the time of the maximum negative pressure,
Compared with the prior art shown in FIG. 2, the inflow velocity of the liquid into the one-way valve immediately before the one-way valve is reduced more quickly, and the kinetic energy of the liquid immediately before the one-way valve is reduced more quickly. To do.

Therefore, in the present invention, the amount of the liquid passing through the one-way valve for preventing backflow in the suction side pipe in accordance with the law of inertia, which is caused by this kinetic energy, is greater than that in the prior art shown in FIG. Decrease.

[0016]

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 reference numerals as those in FIG. 2 are attached to the same parts / members as those in FIG. 2, and in the following description, based on FIG. The description of the same parts / members and the like as already explained in 1. will be omitted.

In one embodiment of the present invention, as shown in FIG. 1, a soft tube 115 made of synthetic resin (outer diameter 6 mm, inner diameter 4 mm, minimum bending radius 12 mm) is a reciprocating pump. 20 has a suction portion 21 and a joint 13a
2 to the soft tube 115 having the same specifications as the suction tube 11 of FIG.
m, inner diameter 4 mm, minimum bending radius 30 mm) is joint 11
The suction tube 111 is formed by the soft tube 115 and the hard tube 116, and the suction tube 111 and the suction passage 23 in the pump 20 form the pump 2
A zero suction side conduit 102 is formed.

Further, the discharge pipe 12 and the discharge flow passage 24 in the pump 20 form a discharge side pipe line 3 of the pump 20, and the discharge side pipe line 3 and the suction side pipe line 102 form a liquid pressure feed pipe. The path 100 is formed. The discharge pipe 12 has the same specifications as the hard tube 116, and is the same as the discharge pipe 12 of FIG.

The liquid pumping line 100 has a pump 20.
Suction passage 2 in the pump 20 in the suction side pipeline 102 of the
A first one-way valve 30a, which is a one-way valve for backflow prevention, is arranged at 3, and the soft tube 115 is provided in the suction-side conduit 102 on the downstream side of the first one-way valve 30a in the pumping direction C of the liquid W.
A second one-way valve 30b, which is a one-way valve for backflow prevention, is arranged in the discharge flow path 24 in the pump 20 in the discharge side pipe line 3 of the pump 20.

In the illustrated embodiment, the liquid W, which is ink, is pumped by the pump 20 using the liquid pressure supply conduit 100 described above.
While the liquid W is sucked toward the pump 20 by a predetermined amount intermittently by driving, the negative pressure generated in the suction side pipe line 102 by the drive of the pump 20 when sucking the liquid W toward the pump 20. When the negative pressure during the intermittent pumping of the liquid W in the soft tube 115 is contracted from the maximum negative pressure during that time, the contraction amount of the soft tube 115 is reduced at the maximum negative pressure. The flow passage cross-sectional area of the soft tube 115 is made larger than the flow passage cross-sectional area at the maximum negative pressure.

In the illustrated embodiment, the pump 20 is a reciprocating pump, but the pump 20 is not limited to a reciprocating pump, and a rotary pump such as a gear pump or a screw pump, a centrifugal pump or an axial flow pump. May be 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 pipeline by the rotation of the impeller, so that the liquid W is discharged from the discharge port of the liquid pumping pipeline. In order to intermittently discharge, it is necessary to control ON / OFF of the rotation of the impeller or the like. However, the reciprocating pump does not need to be controlled, so that the pump 20 is preferably a reciprocating pump.

In the illustrated embodiment, since the pump 20 is a reciprocating pump, the suction side pipe line 1 of the pump 20.
02 has a first one-way valve 30a for backflow prevention, and a second one-way valve 30b for backflow prevention in the discharge side conduit 3 of the pump 20.
However, when the pump 20 is a rotary pump, a centrifugal pump, an axial flow pump, or the like, a one-way valve for preventing backflow is provided only in the suction side pipe line 102 of the pump 20. good.

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

By the way, in the illustrated embodiment, the outer diameter and the inner diameter of the soft tube 115 are such that the hard tube 116 forming the suction pipe 111 of the liquid pressure feeding pipeline 100 and the hard tube forming the discharge tube 12 of the liquid pressure feeding pipeline 100. However, the outer diameter and inner diameter of the soft tube 115 are not limited to the same dimensions as the outer diameter and inner diameter of each hard tube.

The soft tube 115 has an outer diameter of 6
However, the specification of the soft tube 115 is not limited to these numerical values. By adjusting the specifications and the length of the soft tube 115, it is possible to minimize the dripping of the liquid W from the discharge port 4 of the liquid pressure supply conduit 100.

Further, the hard tube 116 forming the suction pipe 111 and the hard tube forming the discharge pipe 12 have the same specifications, and the specifications are an outer diameter of 6 mm and an inner diameter of 4 m.
m, minimum bending radius of 30 mm, but suction pipe 11
The hard tube 116 forming 1 and the hard tube forming the discharge pipe 12 are not limited to the same specifications, and the specifications are 6 mm in outer diameter, 4 mm in inner diameter, and 30 m in minimum bending radius.
It is not limited to m.

Further, the pipes other than the soft tube 115 in the suction pipe 111 and the discharge pipe 12 are hard tubes made of synthetic resin, but the pipes other than the soft tube 115 in the suction pipe 111 and the discharge pipe 12 are made of synthetic resin. The pipe is not limited to a hard tube made of metal, and may be a pipe made of metal or synthetic resin, for example.

In the illustrated embodiment, the soft tube 11
5 and the hard tube 116 form the suction tube 111, but the suction tube 111 may be formed of only the soft tube 115.

By the way, in an experiment in which the suction pipe 111 of FIG. 1 is formed of only the soft tube 115 and a predetermined reciprocating pump is used as the pump 20 of FIG. 1, compared with the conventional technique shown in FIG. It was possible to obtain a good experimental result that almost no dripping of the liquid W from the discharge port 4 of the liquid pressure feeding conduit 100 of FIG.

Further, in the illustrated embodiment, the liquid W is intermittently pressure-fed by the pump 20 in the liquid pressure-feeding conduit 100 by a predetermined amount. However, the liquid W is not limited to the ink, and the water is not limited to the ink. Any kind of 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 negative pressure during the intermittent intermittent feeding of the liquid in the soft tube decreases from the maximum negative pressure during that period, the conventional method shown in FIG. Compared with the technology, the inflow speed of the liquid to the one-way valve for backflow prevention of the suction side pipe is reduced more quickly, and the amount of the liquid passing through the one-way valve according to the law of inertia is reduced. It is possible to reduce the amount of liquid dripping that occurs at the discharge port of the liquid pressure supply pipe each time the fixed amount of liquid is intermittently pressure-fed, as compared with the conventional technique shown in FIG.

[Brief description of drawings]

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

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

[Explanation of symbols]

 4 Discharge Port of Liquid Pumping Line 20 Pump 30a One-way Valve for Backflow Prevention of Suction Side 100 Liquid Pumping Line 102 Pump Suctioning Line 115 Soft Tube C Pumping Direction of Liquid W Liquid

Claims (1)

[Claims] 1. A liquid pressure-feeding line that has a one-way valve for preventing backflow in at least a suction side line of the pump and intermittently feeds a predetermined amount of liquid by driving the pump,
A soft tube made of a synthetic resin is used for the suction side conduit on the downstream side of the one-way valve in the liquid pumping direction, and the suction side conduit is used when the liquid is sucked toward the pump by driving the pump. The soft tube is contracted by the negative pressure generated therein, and when the negative pressure during the intermittent pumping of the liquid in the soft tube decreases from the maximum negative pressure during that period, the contraction amount of the soft tube is reduced. Reducing the contraction amount at the time of the maximum negative pressure to increase the flow passage cross-sectional area of the soft tube from the flow passage cross-sectional area at the time of the maximum negative pressure,
A method for preventing liquid from dripping from a discharge port in a liquid pressure supply pipe line.