JPH0514193Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a piston type pump for liquid delivery, and is particularly used for injectors for liquids such as solutions, concentrated solutions such as chemicals, water, and detergents. This invention relates to a piston type pump for liquid feeding. The present invention also relates to a piston-type pump for a dispenser of an automatic analyzer, and in particular,
The present invention relates to a piston-type pump for injecting liquids such as specimens such as plasma and urine, diluents, water, reagents, detergents, etc. handled by automatic analyzers, such as a piston-type pump such as a dispenser, such as a syringe.

(B) Prior art In an automatic analyzer, a certain amount of a sample or other reagent is injected into a reaction tube, or a certain amount of other detergent or other certain amount of dilution water, etc. is injected into a reaction tube. An automatic dispenser is used to introduce the tube.

Such an automatic dispenser has a discharge nozzle, a conduit,
It consists of a syringe, a switching valve, and a driving part.
Various types of syringe barrels are used, such as a short barrel type and a multiple barrel type for simultaneous dispensing. Such syringe-type reciprocating pumps are required to accurately dispense a fixed amount of variously determined amounts without causing any change in the internal volume of the cylinder, and in addition, to maintain the sealing between the cylinder and the piston. In order to ensure sufficient liquid tightness, it is made of materials with excellent corrosion and abrasion resistance, such as glass materials or synthetic resin materials such as nylon, vinyl chloride, Teflon, polyethylene, and composite materials thereof. has been done.

(c) Problems that the invention aims to solve However, for example, in automatic reagent analyzers,
For example, inorganic phosphorus analysis uses an analytical reagent solution containing 10% sulfuric acid, creatinine analysis uses an alkaline solution with a pH of 12 or higher, and bilirubin analysis uses a saturated caffein solution. However, the piston type pumps used for this purpose, such as syringe barrels, are not all corrosion resistant in terms of materials. Conventionally, when a piston-type pump such as a syringe barrel is used for a certain period of time, the sliding parts wear out and the sealing ability decreases, causing fluid leakage that contaminates or corrodes peripheral equipment, causing problems. be. Moreover, precipitation of crystals from a saturated solution or precipitates due to mutual reactions between reagents results in accelerated wear of the sliding parts of the cylinder and piston, prompting replacement of the piston head and cylinder, and increasing running costs. This is a problem.

Further, such a decrease in the sealing between the cylinder and the piston head causes a change in volume, resulting in poor dispensing precision and a decrease in analysis precision, which is a problem.

The purpose of this invention is to solve problems caused by corrosion and abrasion of the sliding parts of the cylinder and piston head due to liquid in piston-type pumps for metered liquid delivery used in liquid delivery equipment of dispensing devices. It is said that

(d) Means for solving the problem The present invention is a metering liquid transfer device used in liquid transfer equipment such as a dispenser that prevents corrosion and wear between the cylinder and the piston head due to the liquid being transferred. The purpose is to provide pistons for

Furthermore, the present invention provides a solution by covering the cylinder and piston head sliding parts with a liquid that is insoluble in the liquid to prevent them from coming into contact with the liquid being fed.

That is, the present invention provides a piston type pump for liquid delivery that includes a piston in a cylinder that communicates with a flow path switching valve, in which a liquid layer that is insoluble with respect to the liquid to be delivered is provided on the surface of the piston on the liquid contact side. A piston-type pump for liquid delivery is characterized by:

In this invention, the piston type pump for liquid delivery is
Includes plunger pumps. In addition, in the present invention, the liquid layer that is insoluble in the liquid to be delivered is
It is used to isolate the piston head or plunger head from the liquid being pumped, and it is made of a material that is inert, insoluble, or difficult to use with respect to the liquid being pumped, so as not to change the composition of the liquid being pumped. Must be soluble.

Further, when the reciprocating pump is arranged with the suction valve and the discharge valve located above the cylinder, it is preferable that the specific gravity is higher than that of the liquid to be fed.

Such a liquid is selected depending on the liquid to be fed, but it is preferable that it has not only an isolating effect but also a lubricating effect. When the liquid to be sent is water or an aqueous solution, examples of such liquids include, for example,
There are silicone oils such as methylphenyl silicone oil. However, in addition to these, fluorine silicone oil, fluorocarbon, etc. are also used.

(E) Effect The present invention forms a liquid layer on the working surface of the piston or plunger that is insoluble in the liquid to be pumped. Alternatively, liquid can be delivered without direct contact with the plunger head. Therefore, even if solute is precipitated by feeding a saturated solution, the precipitated solute will not come into contact with the cylinder and piston head or plunger head because the cylinder is covered with a liquid layer that has poor affinity for the solvent. It does not get into the sliding parts, and there is no wear on the piston head or plunger head and cylinder.

(F) Example Hereinafter, one embodiment of the piston-type reciprocating pump of the present invention will be described with reference to the attached drawings, but the present invention is not limited in any way by this description and examples. do not have.

The figure is a schematic explanatory diagram of an embodiment of the piston-type reciprocating pump of the present invention.

A reciprocating pump 1 has a piston 3 in a cylinder 2.
A piston actuating rod 4 is connected to the piston 3. A silicone oil layer 6 is formed on the surface 5 of the piston head. The suction and discharge passage 7 of the cylinder 2 is connected to a three-way flow passage switching valve 8.
Among the remaining channels of this switching valve 8, one channel 10 is connected to a conduit 11 connected to a dispensing nozzle (not shown), and the other channel 12 is connected to a conduit 11 connected to a dispensing nozzle (not shown). It connects to a conduit 13 which is inserted at one end into a container (not shown). The flow path switching valve 8 rotates the rotor 14 by 180 degrees,
Via the T-junction 15 of the rotor 14, the suction and discharge channel 7 of the cylinder 2 can be connected to a conduit either on the dispensing nozzle side or on the reagent container side.

Since the reciprocating pump 1 of this example is configured as described above, the piston 3 is actuated by actuating a drive device (not shown) such as a crank or cam that is engaged with the piston actuating rod. When moved upward, the reagent 16 sucked into the cylinder 2 is
Suction and discharge path, T-junction 15 of rotor 14, conduit 1
1 to a reaction tube (not shown) from a dispensing nozzle. When the reagent dispensing is completed, the three-way flow path switching valve is rotated 180 degrees to communicate the suction and discharge path 7 of the cylinder 2 with the conduit 13 whose one end is inserted into the reagent container. Then, when the drive device is activated to move the piston 3 downward, the reagent 16 is sucked into the cylinder 2 via the conduit 13, the T-junction 15 of the rotor 14, and the suction/discharge path 7. Once the reagent 16 has been sucked into the cylinder, the drive device is operated again to move the piston 3.
is moved upward, and the reagent 16 in the cylinder 2 is dispensed from the dispensing nozzle.

In this way, in this example, during the suction and discharge processes of the reagent 16, the silicone oil layer on the cylinder head 5 is stably formed, so that the reagent 16 does not come into contact with the surface 5 of the piston head. corrosion and wear of the piston head were significantly reduced.

Such corrosion and wear of the piston head is similar, for example, in the case of other fluorosilicone oils and fluorocarbons.

Furthermore, when the reciprocating pump of this example was used in a sample dispensing process, a diluent dispensing process, a cleaning agent dispensing process, etc., corrosion and wear were reduced as in the reagent dispensing process of this example.

(g) Effects of the invention In the piston type reciprocating pump of the invention,
Since a liquid layer that is insoluble in the liquid to be delivered is formed on the working surface of the piston or plunger, unlike conventional piston-type reciprocating pumps, the liquid to be delivered, such as the liquid to be dispensed, is There is no direct contact between the piston head or plunger, reducing corrosion and wear. Therefore, compared to conventional piston-type reciprocating pumps, the number of liquid leaks within the same period is reduced, and contamination and corrosion of peripheral equipment due to this can be prevented.

In this way, in the piston-type reciprocating pump of the present invention, since the piston head does not come into direct contact with the liquid to be delivered, such as the liquid to be dispensed, the material of the piston head can be selected regardless of the type of liquid. This makes it possible to select materials that have excellent rigidity in addition to corrosion resistance. Therefore, according to the present invention, it is possible to use the reciprocating pump for a long period of time, and it is also possible to provide an economical piston-type reciprocating pump with low cost and low maintenance costs.

In addition, according to the present invention, a decrease in dispensing accuracy due to corrosion, wear, etc. is avoided even after long-term use, so analysis accuracy is improved compared to conventional piston-type reciprocating pumps. can be measured.

As described above, the piston-type reciprocating pump of the present invention has many advantages over conventional pumps.

[Brief explanation of drawings]

The figure is a schematic explanatory diagram of an embodiment of the piston-type reciprocating pump of the present invention. Regarding the symbols in the diagram, 1 is a reciprocating pump, 2 is a reciprocating pump,
is the cylinder, 3 is the piston, 4 is the piston operating rod, 5 is the piston head, 6 is silicone oil,
7 is a suction and discharge path, 8 is a three-way flow path switching valve, 9, 1
0 and 12 are one way of the three-way flow path switching valve, 11 and 1
3 is a conduit, 14 is a rotor, 15 is a T-junction, and 16 is a reagent.

Claims (1)

[Scope of utility model registration request] A piston-type pump for liquid delivery that includes a piston in a cylinder that communicates with a flow path switching valve, characterized in that a liquid layer that is insoluble in the liquid to be delivered is provided on the liquid-contacting side of the piston. Piston type pump for liquid delivery.