CN109229958B

CN109229958B - Program-controlled injection pump system for corrosion-resistant ultra-trace metal impurities

Info

Publication number: CN109229958B
Application number: CN201810840075.9A
Authority: CN
Inventors: 徐陶然; 蒋小明
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2018-07-27
Filing date: 2018-07-27
Publication date: 2021-05-18
Anticipated expiration: 2038-07-27
Also published as: CN109229958A

Abstract

The invention discloses a corrosion-resistant ultra-trace metal impurity program-controlled injection pump system, relates to the field of fluids, and particularly relates to a corrosion-resistant program-controlled injection pump system. The syringe pump system consists of a syringe and a driving stepping motor thereof. The system and the fluid contact part are made of chemical corrosion resistant polymer materials (fluorine-containing plastics, polypropylene, polyphenylene sulfide, polyether ether ketone, polyethylene and the like). The system at least comprises an injector with a channel, a driving stepping motor and a set of mechanical transmission parts. The driving stepping motor is controlled by a program to realize automatic operation. The metal parts used by the system are sealed in a corrosion-resistant high polymer material box body and are relatively isolated from the external environment, so that the metal parts are prevented from being corroded.

Description

Program-controlled injection pump system for corrosion-resistant ultra-trace metal impurities

Technical Field

The invention relates to the field of fluids, in particular to a chemical corrosion resistant, ultra-trace metal impurity and program controlled injection pump system.

Background

The injection pump system is widely applied to the fields of analytical chemistry, environmental science, chemical industry, environmental protection, food, clinical medicine, life science and the like. The materials of the syringe cylinder of the prior syringe pump comprise glass, quartz, ceramics, metal, plastics and the like, and the materials of the piston thereof comprise glass, ceramics, rubber and the like. Some special fluid application fields (fields of semiconductors, geochemistry, life science and the like) require that fluid equipment has the capability of resisting strong chemical corrosion (nitric acid, hydrochloric acid, sulfuric acid, hydrofluoric acid and the like) and has ultra-trace metal impurities, and the existing injection pump is difficult to meet the requirements. Mainly because glass, quartz, ceramics and metals are difficult to meet the requirement of strong chemical corrosion resistance, for example, hydrofluoric acid can corrode the glass, the ceramics and the metals, and trace metal impurities can be released in a strong chemical corrosion medium; the rubber piston can be corroded in a strong chemical corrosion medium, and trace metal impurities are released;

on the other hand, metal parts of a driving stepping motor and a mechanical transmission device of the existing injection pump system are exposed to corrosive gas atmosphere, and not only are the metal parts easily corroded, but also volatile metal compounds formed by the metal parts are also polluted by potential trace metal impurities.

Disclosure of Invention

The invention provides a corrosion-resistant ultra-trace metal impurity program-controlled injection pump system, which aims to solve the technical problems in the background technology.

The corrosion-resistant ultra-trace metal impurity program-controlled injection pump system mainly comprises 7 parts: the device comprises an injector, an injector needle cylinder fixing sleeve, a mechanical transmission part, a driving stepping motor, a stepping motor driving module, a limit photoelectric switch and a sealing shell.

An injector: for aspirating and injecting fluids. The syringe needle is made of high molecular materials (fluorine-containing plastics, polypropylene and the like) which are resistant to strong chemical corrosion; the injector piston is also made of high polymer materials (fluorine-containing plastics, polypropylene or polyethylene and the like) which are resistant to strong chemical corrosion and have a self-lubricating effect; the injector push rod is made of high polymer materials (polyether-ether-ketone, polyphenylene sulfide or polytrifluorochloroethylene and the like) with high mechanical strength and chemical corrosion resistance.

Fixing a syringe needle: the device is used for fixing the syringe of the injector, preventing the syringe of the injector from moving up and down and preventing the syringe of the high polymer material from deforming, and ensuring the injection precision of the fluid.

Mechanical transmission parts: the stepping motor is used for connecting the injector push rod and the driving stepping motor, and transmitting the motion of the stepping motor to the injector push rod, so that the injector push rod can do vertical accurate motion under the driving of the stepping motor.

Driving a stepping motor: used for driving the syringe push rod connected with the syringe push rod to move up and down.

Limiting the photoelectric switch: the limiting device is fixed on the transmission component which moves up and down and moves together with the transmission component so as to judge the upper and lower limiting positions of the push rod of the injector and limit the push rod of the injector to exceed the upper and lower limiting positions.

Step motor drive module: the stepping motor control system consists of a hardware circuit for controlling the movement of the stepping motor and an embedded driving program.

Sealing the housing: the device is used for supporting the injector, the injector syringe jacket, the mechanical transmission part, the driving stepping motor and the stepping motor driving module, and is also used for sealing the metal parts of the mechanical transmission part, the stepping motor and the stepping motor driving module so as to isolate the metal parts from corrosive media in the environment.

Drawings

Fig. 1A and 1B are front and back structural views of a four-channel, exemplary corrosion-resistant ultra-trace metal impurity program-controlled injection pump system, respectively.

Fig. 2A and fig. 2B are the appearance and the section structure of the syringe fixing sleeve of the injector respectively.

Fig. 3A and 3B are external structures and sectional views of a push rod of the syringe.

Fig. 4A and 4B are an oilless bearing outer structure and a sectional view.

Fig. 5A, 5B, 5C and 5D are front, top, bottom and back views of the syringe push rod connection seat structure, respectively.

Fig. 6 is a linear slide table.

Fig. 7 is a front view of a sealed enclosure of a four-channel, corrosion-resistant ultra trace metal contaminant programmable injection pump system.

Description of the reference numerals

In fig. 1A and 1B, 1-syringe barrel; 2-injector syringe fixing sleeve; 3-liquid discharge and air exhaust holes; 4-the stepping motor drives the lead screw; 5-a linear sliding table; 6-injector push rod connecting seat; 7-photoelectric switch baffle; 8-a screw connector; 9-a stepper motor; 10-sealing the housing; 11-oil free sealed bearings; 12-a syringe push rod; 13-upper and lower limit slot type photoelectric switches; 14-stepper motor driver.

In fig. 2A and 2B, 15-external threads.

In fig. 3A and 3B, 16-annular projecting ribs; 17-a disc; 18-blind hole.

In fig. 5A, 5B, 5C and 5D, 19 — the pusher card.

In fig. 6, 20 — slider.

Detailed Description

The system architecture and the operation of the present invention will be described in detail below for a better understanding of the present invention.

The injector needle cylinder 1 of the system is made of high polymer materials (fluorine-containing plastics, polypropylene and the like) which are resistant to strong chemical corrosion, and the outer side of the injector needle cylinder is sleeved with an injector needle cylinder fixing sleeve 2, so that the up-and-down movement of the injector needle cylinder and the deformation of the injector needle cylinder made of the high polymer materials are prevented, and the fluid injection precision is ensured; the injector syringe fixing sleeve 2 is made of high polymer material with higher mechanical strength, and the thickness of the injector syringe fixing sleeve is thicker so as to ensure the mechanical strength of the injector syringe fixing sleeve; the syringe barrel retaining collar 2 is externally threaded 15 (as shown in figures 2A and 2B) so that it screws into the system's seal housing 11, compressing the outer edge of the lower end of the syringe barrel as it screws, securing the syringe within the system's seal housing 11.

The injector push rod is made of a high polymer material (polytetrafluoroethylene (PTFE), PFA or the like) with self-lubricating effect, high mechanical strength and strong chemical corrosion resistance, and the structure of the injector push rod is shown in fig. 3A and 3B. The upper end of the push rod of the injector is provided with an annular protruding edge, and the size of the annular protruding edge is slightly larger than the inner diameter of the syringe so as to ensure good sealing performance of the syringe and the push rod. The lower end structure of the injector push rod is provided with a disc 17 which is connected with the injector push rod connecting seat 6. The syringe plunger has a blind bore 18 therein.

The oil-free sealed bearing 11 is made of a self-lubricating and strong chemical corrosion resistant polymer material (PTFE or polyetheretherketone PEEK, etc.), a fluororubber O-ring is installed inside the inner diameter of the bearing to enhance the sealing effect, and the structure of the oil-free sealed bearing is shown in fig. 4A and 4B. The oilless sealed bearing 11 isolates the injector space from the mechanical transmission space of the stepping motor below. The oilless sealed bearing 11 has a liquid discharge exhaust hole 3 which is the same as the outside of the injection pump system.

The injector push rod connecting seat 6 is connected with the injector push rod 12 and the stepping motor transmission screw rod 4, and the structure of the injector push rod connecting seat is shown in fig. 5A, fig. 5B, fig. 5C and fig. 5D. The upper end of the injector push rod connecting seat 6 is connected with the lower end of an injector push rod 12; the push rod clamping piece 19 locks the disc at the lower end of the push rod 12 of the injector; the lower end of the injector push rod connecting seat 6 is connected with a stepping motor transmission screw rod 4 through a screw rod nut; the screw rod 4 passes through the center of the connecting seat 6 and is connected with a blind hole of a push rod of the injector; photoelectric switch baffles 7 can be arranged on the left side and the right side of the connecting seat 6, the photoelectric switch baffles 7 move along with the connecting seat 6, and when the connecting seat shields the upper limiting groove type photoelectric switch 13 and the lower limiting groove type photoelectric switch 13, the stepping motor stops immediately. The whole injector push rod connecting seat 6 is arranged on a sliding block 20 of the linear sliding table 5.

The rotating shaft of the stepping motor 9 is connected with the screw rod 4 through the screw rod connector 8, the circular motion of the stepping motor 9 is transmitted to the screw rod 4 and converted into the linear motion of the injector push rod connecting seat 6 through a screw rod nut, and then the injector push rod 12 is pushed to move up and down.

The stepper motor driver 14 is mounted in the rear sealed space of the syringe pump system. The stepper motor driver 14 is composed of stepper motor driving hardware and embedded control software, and controls the motion of the stepper motor.

The above-mentioned unit structures are sealed in a sealed shell 11 made of high-strength and chemical-corrosion-resistant polymer material (polypropylene PP, PFA, PEEK, PPS or polychlorotrifluoroethylene PCTFE) to prevent corrosion of corrosive gas in external environment.

The program-controlled injection pump system for the corrosion-resistant ultra-trace metal impurities, which is provided by the invention, is based on a high polymer material with strong chemical corrosion resistance, realizes the accurate injection of the fluid of the trace metal impurities in a strong chemical corrosion environment through a novel and reasonable mechanical structure design, and can be widely applied to the field of fluid injection with extremely high requirements on the metal impurities and extremely strong chemical corrosion.

The foregoing description of the invention is illustrative and not restrictive, and it will be understood by those skilled in the art that many changes, variations or equivalents may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. The utility model provides a corrosion-resistant super trace metal impurity programme-controlled injection pump system which characterized in that: four unit structures are sealed in a sealed shell (11) made of high polymer materials with high mechanical strength and strong chemical corrosion resistance, and the unit structures are as follows: the syringe is made of a high polymer material with strong chemical corrosion resistance, a syringe fixing sleeve with strong chemical corrosion resistance is arranged outside the high polymer material syringe, the syringe fixing sleeve is screwed into the system sealing shell by adopting a threaded structure, and the bottom of the syringe fixing sleeve presses the convex outer edge at the lower end of the syringe, so that the high polymer material syringe is ensured not to deform and move up and down, and the injection volume precision of the syringe is ensured; the injector push rod is made of high polymer materials with strong chemical corrosion resistance, self-lubricating function and better mechanical strength, and the upper end of the injector push rod is designed into a plurality of layers of annular protruding edges; the injector and the fluid contact part are both made of high molecular materials resistant to strong chemical corrosion, can be used in a strong chemical corrosion medium for a long time, and have the advantage of no precipitation of ultra-trace metal impurities; the injector is isolated from a mechanical transmission device at the lower part of the injector through an oilless sealed bearing, and the oilless sealed bearing is made of high polymer materials with strong chemical corrosion resistance and self-lubricating function; the oil-free sealed bearing is provided with a liquid discharge exhaust hole communicated with the outside; the lower end of the injection push rod is designed into a disc shape and is connected with the upper end of an injector push rod connecting seat through a pair of push rod clamping pieces, the injector push rod connecting seat is arranged on the linear sliding table, the lower end of the injector push rod connecting seat is connected with a screw rod nut, and a screw rod of a stepping motor penetrates through the injector push rod connecting seat through the screw rod nut and is inserted into an injector push rod blind hole; the stepping motor drives the screw rod to rotate, and the screw rod nut drives the injector push rod connecting seat to move up and down on the linear sliding table so as to drive the injector push rod to move up and down; the stepper motor is controlled by driver hardware circuitry and software programming.