JP2002371955A - Reciprocating drive unit and liquid transfer pump using the reciprocating drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reciprocating drive unit and a liquid transfer pump, capable of being used for physical and chemical machine such as a flow injection, generating no noise, and having a long life. SOLUTION: This reciprocating drive unit and the liquid transfer pump comprises a drive portion composed of bellows 21 linearly reciprocating according to thermal expansion/shrinkage of liquid 5 filled in a liquid reservoir portion 1, a pump mechanism portion 4 sucking/discharging the liquid by reciprocating of the drive portion, and a thermo-module 3 by Peltier effect for alternately heating and cooling the liquid reservoir portion 1. The volume of the liquid in the liquid reservoir portion 1 is changed by temperature, thereby actuating the pump mechanism portion 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating drive device which uses expansion and contraction due to a temperature change and is used as a drive source for a pump or other mechanism, and an analytical device such as a flow injection device using the device. To a liquid sending pump.

[0002]

2. Description of the Related Art Conventionally, a liquid feeding pump includes a bellows pump using a bellows, a plunger pump for reciprocating a plunger in a cylinder, a tube pump for sequentially crushing tubes from an upstream side to a downstream side, and a biting pump. There are various types of liquid feed pumps, such as a gear pump that rotates a combined gear and a rotary pump that rotates a triangular rotor in a gourd-shaped cylinder. These pumps use an electric motor as a drive source, and use the rotation as it is as a rotational drive or convert the rotation into a reciprocating motion through a motion conversion mechanism such as a cam mechanism or a crank mechanism. .

[0003] Among these various pumps, plunger pumps, in which the operation amount and the liquid transfer amount are always in a fixed relation, are often used for the quantitative liquid transfer of the physical and chemical equipment such as flow injection.

[0004]

In the above-described conventional liquid feed pump, since the driving source is a motor, the life of the liquid feeding pump often depends on the life of the electric motor as the driving source. Further, the electric motor always emits noise when it is driven to rotate, and there is a problem that the level of the noise increases as the use period elapses.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a noiseless and long-life reciprocating drive device and a liquid feed pump using the device.

[0006]

SUMMARY OF THE INVENTION A reciprocating drive according to the present invention for solving the above-mentioned conventional problems and achieving the intended object is characterized by a liquid reservoir in which an expansion and contraction liquid is sealed in a hollow interior. And a drive unit that reciprocates linearly in response to thermal expansion and contraction of the liquid in the liquid reservoir, and heating and cooling means for alternately heating and cooling the liquid reservoir. .

[0007] The features of the liquid feed pump according to the present invention are as follows.
A liquid reservoir in which the expansion / contraction liquid is sealed in the hollow interior, a drive unit which reciprocates in a linear direction corresponding to the thermal expansion and contraction of the liquid in the liquid reservoir, and a pump mechanism which sucks and discharges the liquid by the reciprocation of the drive unit And heating and cooling of the liquid reservoir are alternately performed.

In both of the above-mentioned inventions, the heating and cooling means uses a thermo module which generates a heat-generating action and a heat-absorbing action by the Peltier effect, and changes the polarity of the DC current applied to the thermo-module to control the heating and cooling. It is preferable that the cooling be performed alternately, and that the drive unit be a bellows-shaped bellows connected to the liquid reservoir.

[0009] In the above liquid feed pump, the pump mechanism is a plunger pump mechanism having a cylinder and a plunger reciprocating in the cylinder, and it is preferable that the plunger is linked to a drive unit.

[0010]

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

The drawings show a liquid feed pump constituted by using a reciprocating drive device according to the present invention. In the figure, reference numeral 1 denotes a liquid reservoir, 2 denotes a drive unit, and 3 denotes a thermo module as a heating / cooling means. There is a reciprocating drive device. The reciprocating drive device operates the pump mechanism 4 to constitute a liquid sending pump.

The liquid reservoir 1 is a flat liquid reservoir main body 1.
1, the hollow interior of the main body 11 is
It has become. The reservoir main body 11 is formed of a metal material having high thermal conductivity in a hollow shape, and has upper and lower walls connected to each other by reinforcing ribs 12 so that the reservoir 1 is not easily deformed.

The drive unit 2 comprises a bellows 21. The bellows 21 has a fixed end side on which the liquid reservoir main body 1 is provided.
1 so that the moving end side is moved in the axial direction by the internal pressure.

An expansion / contraction liquid 5 having a large thermal expansion coefficient and a constant or nearly constant expansion coefficient with respect to a temperature change is sealed in the liquid reservoir 1 and the bellows 21. The volume of the expansion / contraction liquid changes due to the temperature change. The change causes the bellows 21 to extend or contract.

Thermomodules 3 and 3, which are heating and cooling means, are fixed to both sides of the liquid reservoir main body 11 so that heating or cooling is performed. The thermo-module 3 uses a plate-shaped module in which at least one side is absorbed (cooled) or radiated (heated) by supplying a direct current using the Peltier effect.

A pair of power terminals 31 and 32 of the thermo module 3 are connected to a power supply 33,
In the Japanese Patent Application Laid-Open Publication No. H11-27139, the current is supplied by changing the + -polarity of the DC current at desired set times.

Further, the pair of thermo modules 3 is
Each of the heat transfer surfaces 3a,
The current is supplied so that 3a is on the heat dissipation side or heat absorption side at the same time.

A plunger pump mechanism is used for the pump mechanism section 4, and a plunger 42
Are inserted so that they can reciprocate while maintaining gas-liquid tightness. A liquid suction path 44 and a liquid supply path 45 are communicated with the cylinder head 43. Check valves 44 a and 45 a are provided in each of the liquid paths, and the cylinder 41 is moved from the liquid suction path 45 to the cylinder 41 by the operation of pulling out the plunger 42. The liquid is sucked into the inside, and the liquid feed path 45
, The liquid in the cylinder 41 is pushed out.

The tip of the plunger 42 of the pump mechanism 4 is brought into contact with the tip of the bellows 21 of the drive unit 2 described above, and the operation of the plunger 42 on the pushing side is reduced.
1 in the extension direction. The operation of the plunger 42 in the withdrawal direction is performed by the coil spring 46.
Of the bellows 21 in the contraction direction of the bellows 21 by the elasticity of the bellows.

The liquid feed pump having the above-described configuration supplies a DC current to the thermomodules 3 and 3 by the power supply device 33 at predetermined time intervals while changing the polarity of + and-.
Heating and cooling of the liquid reservoir main body 11 are alternately performed, whereby the volume of the expansion / contraction liquid 5 in the liquid reservoir 1 changes, and the bellows 21 of the drive unit 2 expands and contracts. Following this operation, the plunger 42 of the pump mechanism 4 is pushed and pulled out.

[0021]

As described above, the reciprocating drive device according to the present invention has a liquid reservoir portion in which expansion and contraction liquid is sealed in a hollow interior, and reciprocates in a linear direction corresponding to the thermal expansion and contraction of the liquid in the liquid reservoir portion. By having a driving unit that operates and a heating and cooling unit that alternately heats and cools the liquid reservoir, the reciprocating drive is performed by expansion and contraction due to a change in the temperature of the liquid. There is no portion where friction occurs due to noise, there is no noise, and the life is significantly longer than that of the conventional electric mechanism.

By configuring the liquid feed pump so as to operate the pump mechanism for sucking and discharging liquid by the reciprocating operation of the reciprocating drive device, a noiseless and long-life liquid feed pump is formed.

Further, in the reciprocating drive device and the liquid sending pump, a thermo module which generates heat and heat is absorbed by the Peltier effect is used as the heating and cooling means, and the polarity of the direct current supplied to the thermo module is changed. By performing the heating and the cooling alternately by doing so, a compact and small reciprocating drive device and a liquid sending pump can be configured, which contributes to the downsizing that enables the carrying of the analytical instrument.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view schematically showing a liquid feed pump according to the present invention.

FIG. 2 is a plan view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid storage part 2 Drive part 3 Thermo module 3a, 3a Heat transfer surface 4 Pump mechanism part 5 Expansion / contraction liquid 11 Liquid storage main body part 12 Reinforcement rib 21 Bellows 31, 32 Power supply terminal 33 Power supply device 41 Cylinder 42 Plunger 43 Cylinder head Part 44 Liquid suction path 44a Check valve 45 Liquid feed path 45a Check valve 46 Coil spring

Claims (7)

[Claims] 1. A liquid reservoir in which an expansion / contraction liquid is sealed in a hollow interior, a drive unit reciprocating in a linear direction corresponding to thermal expansion / contraction of the liquid in the liquid reservoir, and heating and cooling of the liquid reservoir And a heating / cooling means for alternately performing the above operations. 2. A thermo module which generates heat and absorbs heat by a Peltier effect as heating and cooling means,
The reciprocating drive device according to claim 1, wherein heating and cooling are alternately performed by changing a polarity of a direct current supplied to the thermo module. 3. The reciprocating drive device according to claim 1, wherein the drive portion is a bellows-shaped bellows communicating with the liquid reservoir. 4. A liquid reservoir in which an expansion / contraction liquid is sealed in a hollow interior, a driving unit reciprocating in a linear direction corresponding to thermal expansion / contraction of the liquid in the liquid reservoir, and a suction / discharge operation by the reciprocating operation of the driving unit. A liquid feed pump comprising: a pump mechanism for liquid; and a heating / cooling means for alternately heating and cooling the liquid reservoir. 5. A heating / cooling means using a thermo module which generates heat and absorbs heat by a Peltier effect,
The liquid supply pump according to claim 4, wherein heating and cooling are alternately performed by changing a polarity of a direct current supplied to the thermomodule. 6. The liquid feed pump according to claim 4, wherein the drive section is a bellows-shaped bellows communicated with the liquid storage section. 7. A pump mechanism comprising a plunger pump mechanism having a cylinder and a plunger reciprocating in the cylinder, wherein the plunger is interlocked with a drive unit. 7. The liquid sending pump according to 6.