CN116025537A

CN116025537A - Liquid chromatographic pump

Info

Publication number: CN116025537A
Application number: CN202211629518.2A
Authority: CN
Inventors: 丁旭; 张鑫; 尹杨青; 朱松奎; 陈文辉; 谢传东; 杜周
Original assignee: Anhui Wanyi Science and Technology Co Ltd
Current assignee: Anhui Wanyi Science and Technology Co Ltd
Priority date: 2022-12-15
Filing date: 2022-12-15
Publication date: 2023-04-28

Abstract

The invention discloses a liquid chromatographic pump which comprises a pump seat, a driving unit, a transmission unit, a plunger rod, a low-pressure body and a high-pressure body, wherein the driving unit, the transmission unit, the plunger rod, the low-pressure body and the high-pressure body are all arranged in the pump seat, the plunger rod and the transmission unit are in floating connection by adopting a flexible connecting mechanism, the flexible connecting mechanism comprises a support frame and a limit groove, the support frame is fixedly arranged on the end face of the plunger rod, the limit groove is arranged on the end face, close to the plunger rod, of the transmission unit, and a ball is arranged in the limit groove, so that the support frame and the transmission unit are connected in a point contact mode, and the support frame is also connected with a stabilizing mechanism. The invention has simple and reliable structure and smaller dead volume, can eliminate the inclination or shaking of the plunger rod and prevent the service life of the sealing ring from being influenced.

Description

Liquid chromatographic pump

Technical Field

The invention relates to a liquid chromatography technology, in particular to a liquid chromatography pump.

Background

In the development process of the liquid chromatograph, the performance of the whole machine is higher and higher, the requirement is also continuously improved, and the pressure resistance and stability requirements on the infusion pump are also higher and higher.

The liquid chromatograph infusion pump in the liquid chromatograph is used for delivering liquid at a constant flow rate, and the sample is transported to the detection system for detection through the mobile phase. The infusion pump is usually a cam pump and a linear motor pump, the cam pump drives a main cam and an auxiliary cam to rotate through a motor so as to drive a plunger rod to reciprocate, and the transmission of liquid is realized through the curve matching of the main cam and the auxiliary cam; the linear motor pump controls the linear motor to make the plunger rod reciprocate through the movement of the screw rod so as to achieve the purpose of transfusion. In any mode, the pump head adopts a high-pressure sealing ring and a low-pressure sealing ring to realize the sealing of liquid, and a pipeline system in a high-pressure area realizes the constant-flow unidirectional conveying of the liquid through a main unidirectional valve and an auxiliary unidirectional valve.

Under the serial working condition, the inlet and the outlet of the main pump head are provided with one-way valves for active liquid suction, the auxiliary pump head is used for passive liquid suction, the compression spring compresses and restores the plunger rod to be pushed against the cam, so that the motion of the plunger rod accords with the curve characteristic of the cam, and the mechanism realizes that the main pump head and the auxiliary pump head alternately work cooperatively to achieve stable liquid suction, but the working characteristic of the reciprocating plunger pump inevitably generates larger liquid suction pulsation. And the infusion pump that adopts cam to drive the push rod subassembly motion, and then the plunger rod motion is driven by the push rod subassembly, although can realize pumping high-pressure fluid, fluid pulsation is unavoidable, and simultaneously, at plunger rod in reciprocating motion's in-process, its continuous and sealing washer friction takes place, but owing to the slope or the shake of plunger rod, can make the sealing washer damage accelerate, influences life and the sampling precision of sealing washer.

Disclosure of Invention

In order to solve the above-mentioned shortcomings in the prior art, an object of the present invention is to provide a liquid chromatography pump, which has a simple and reliable structure and a small dead volume, and can eliminate the inclination or shaking of the plunger rod, and prevent the life of the seal ring from being affected.

The technical scheme adopted for solving the technical problems is as follows: the liquid chromatographic pump comprises a pump seat, a driving unit, a transmission unit, a plunger rod, a low-pressure body and a high-pressure body, wherein the driving unit, the transmission unit, the plunger rod, the low-pressure body and the high-pressure body are all arranged in the pump seat;

the flexible connecting mechanism comprises a support frame and a limit groove, wherein the support frame is fixedly arranged on the end face of the plunger rod, the limit groove is formed in the end face, close to the plunger rod, of the transmission unit, and balls are arranged in the limit groove, so that the support frame is connected with the transmission unit in a point contact mode;

the support frame is also connected with a stabilizing mechanism.

Optionally, a guide seat adapted to the transmission unit is arranged in the pump seat, so that the transmission unit reciprocates in the guide seat along a straight line.

Optionally, the transmission unit includes movable rod, cam and installs the transmission shaft of cam, be equipped with in the guide holder be used for passing the guiding hole of movable rod, the movable rod pass through the synovial membrane with guiding hole sliding connection.

Optionally, the driving unit comprises a motor and belt wheels respectively installed in an output shaft and a transmission shaft of the motor, and the two belt wheels are connected through a belt.

Optionally, the stabilizing mechanism comprises two pull pins arranged in the supporting frame and a connecting rod fixedly arranged in the end face of the guide seat, which is close to one side of the plunger rod, wherein the connecting rods are in one-to-one correspondence with the pull pins, and a first spring is connected between the paired pull pins and the connecting rods and is in a stretching state;

the positions of the two pull pins in the support frame are symmetrical relative to the center of the support frame, and the two connecting rods connected with the same support frame are distributed in the guide seat along the same vertical line.

Optionally, the ball is connected with the bottom of the limit groove through a second spring, and the second spring is in a compressed state;

the inner diameter of the limiting groove is larger than the diameter of the ball, so that the ball can swing freely in the limiting groove, the end face of the limiting groove is detachably connected with a locking end cover, and a through hole exposing part of the ball is formed in the locking end cover.

Optionally, the low-pressure body is fixedly connected with the guide seat through guide rods, the number of the guide rods is four, and the area surrounded by the four guide rods in the guide seat is parallelogram;

two ends of the supporting frame are respectively connected with two guide rods positioned on the same side in a sliding manner.

By adopting the technical scheme, the invention has the following beneficial effects:

1. the plunger rod and the transmission unit are connected in a point contact floating connection mode, so that the phenomenon of shaking or tilting of the plunger rod can be prevented when the transmission unit transmits the plunger rod, radial friction of the plunger rod to the sealing ring is effectively prevented, the service life of the sealing ring is ensured, and the risk of liquid leakage is reduced;

2. the invention adopts the support frame as the intermediate piece to drive the driving torque of the driving unit, and the support frame is internally provided with the stabilizing mechanism, thereby ensuring the stability of the driving.

Drawings

FIG. 1 is a schematic diagram of the structure of the present invention;

FIG. 2 is a cross-sectional view of the present invention;

FIG. 3 is a schematic view of the connection of the plunger rod of the present invention;

FIG. 4 is a schematic view of the connection of the support frame of the present invention;

FIG. 5 is a schematic illustration of the connection of a guide rod to a guide holder of the present invention;

fig. 6 is a schematic diagram of the connection of the guide rod to the low pressure body of the present invention.

Detailed Description

The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings.

It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

As shown in fig. 1, the present invention discloses a liquid chromatography pump comprising a pump base 1 and a driving unit, a transmission unit, a plunger rod, a low pressure body 2 and a high pressure body 3 installed in the pump base 1.

As shown in fig. 1 and 2, in the present invention, a driving unit is used to provide driving force to the entire pump. The driving unit is fixedly installed at one end of the pump base 1, and its position is not movable. In general, the motor 4 is a power source of a driving unit, and in the lobe pump, the motor 4 is used for driving a cam to rotate, and the plunger rod is driven to reciprocate when the cam rotates, so that infusion is realized. Specifically, in one embodiment of the present invention, the driving unit further includes two pulleys, one of which is fixedly installed at the output shaft of the motor 4, and the other of which is fixedly installed at the end of the transmission shaft of the cam, and the two pulleys are connected by a belt to achieve belt transmission.

In the present invention, as shown in fig. 2, the transmission unit includes a cam 5, a transmission shaft 6, and a moving lever 7 engaged with the cam 5. The transmission shaft 6 is installed in the pump seat 1 through a belt seat bearing 33, wherein the end part of the transmission shaft 6 is fixedly provided with one of the belt pulleys, and the transmission shaft 6 is connected with the output shaft of the motor 4 through belt transmission. Specifically, the diameters of the two pulleys are not uniform, wherein the large pulley is fixed to the transmission shaft 6 and the small pulley is fixed to the output shaft of the motor 4. The cams 5 are fixedly arranged in the transmission shaft 6, and normally, the plunger rod is provided with a main plunger rod and a secondary plunger rod, and the main plunger rod and the secondary plunger rod are respectively transmitted through the cams, so that in the invention, the number of the cams 5 and the moving rods 7 is respectively two, and the two cams 5 are arranged with a phase difference, so that the movement of the plunger rod reaches the condition of pumping and transfusion. In addition, in the present invention, in order to facilitate the reciprocating motion of the moving rod 7, a guide seat 8 may be provided in the pump seat 1, and guide holes 9 penetrating both ends may be provided in the guide seat 8, and the moving rod 7 may be slidably connected in the guide holes 9 through a sliding film. One end of the moving rod 7 is connected to the rim of the cam 5 through a cam follower 10, and the cam follower 10 is connected to the end of the moving rod 7 through a pin 11. An optical coupler 16 can be installed at one end of the transmission shaft 6 far away from the belt wheel, and a photoelectric switch 27 is installed at the corresponding position of the pump seat 1, so that the rotation state of the transmission shaft 6 can be monitored in real time and fed back to a control system of liquid chromatograph in real time, and the rotation condition of the motor 4 can be corrected.

In the invention, a limit groove 12 is formed at the end part of the moving rod 7 far away from the cam 5, and a ball 13 is connected in the limit groove 12, wherein the ball 13 is preferably a smooth-surface steel ball. The ball 13 is connected in the limit groove 12 by a second spring 14 and is screwed with a locking end cap 15 at the end of the moving rod 7, so that the ball 13 is restrained in the limit groove 12. In the present invention, a through hole having a smaller diameter than the ball 13 is formed in the center of the locking end cap 15 so that a part of the ball 13 can pass out of the through hole. Based on this, the second spring 14 should always be in a compressed state so that the balls 13 are pressed against the locking end cap 15, so that part of the balls 13 are exposed from the through holes. In addition, the inner diameter of the limit groove 12 should be larger than the diameter of the ball 13 so that the ball 13 can generate micro motion effect in the axial direction and the radial direction of the limit groove 12 in the limit groove 12.

In the present invention, as shown in fig. 2 and 3, the plunger rod includes a main plunger rod 17 and a sub plunger rod 18, and the main plunger rod 17 and the sub plunger rod 18 are connected to the corresponding moving rod 7, respectively, so that the moving rod 7 drives the main plunger rod 17 and the sub plunger rod 18. Specifically, the main plunger rod 17 and the auxiliary plunger rod 18 are respectively connected with the moving rod 7 through the supporting frame 19, and the supporting frame 19 is of a flat plate structure, so that the contact mode of the balls 13 and the supporting frame 19 is point contact, and when the moving rod 7 inclines or shakes, the radial force of the main plunger rod 17 and the auxiliary plunger rod 18 can be eliminated by the balls 13, so that the service life of the sealing ring is prolonged, and the risk of liquid leakage is reduced. Since the balls 13 can generate radial micro-motion when driving with the support 19, the balls 13, the support 19 and the limit groove 12 can be regarded as a flexible connection mechanism, which can realize floating connection of the plunger rod and the moving rod 7.

As shown in fig. 2 and 4, in order to secure the stable connection between the support 19 and the balls 13, a stabilizing mechanism is also connected to the support 19. Specifically, the stabilizing mechanism comprises two pull pins 20 arranged in the supporting frame 19, and a connecting rod 21 fixedly arranged in the end face of the guide seat 8, which is close to one side of the plunger rod, wherein the connecting rod 21 is an L-shaped rod, the connecting rod 21 corresponds to the pull pins 20 one by one, a first spring 22 is connected between the paired pull pins 20 and the connecting rod 21, and the first spring 22 is always in a stretching state. In addition, in order to further ensure the stability of the support frame 19, the positions of the two pull pins 20 in the support frame 19 are symmetrical relative to the center of the support frame 19, and the two connecting rods 21 connected with the same support frame 19 are distributed along the same vertical line in the guide seat 8, so that the distribution of the first springs 22 is rectangular, the pulling force of the first springs 22 is uniform, and the stability of the movement of the plunger rod is ensured.

In the present invention, as shown in fig. 2, 5 and 6, the low pressure body 2 and the guide seat 8 are fixedly connected through the guide rod 23, so as to position the low pressure body 2, and two ends of the guide rod 23 are respectively connected with the low pressure body 2 and the guide seat 8 through the locking chuck 24. The guide rods 23 are four, and two ends of the support frame 19 are respectively connected with the two guide rods 23 positioned on the same side in a sliding way through sliding bearings 25. The area enclosed by the positions of the four guide rods 23 in the guide seat 8 is parallelogram-shaped so as to ensure that the support frame 19 is inclined.

In the present invention, as shown in fig. 2, the low pressure body 2 and the high pressure body 3 are fastened by screw connection, and a support plate 26 is further connected between the low pressure body 2 and the guide holder 8, so as to strengthen the fastening degree of the low pressure body 2. The high-pressure area and the low-pressure area are formed between the low-pressure body 2 and the high-pressure body 3 through the high-pressure sealing ring 28 and the low-pressure sealing ring 29, and the high-pressure sealing ring 28 and the low-pressure sealing ring 29 are tightly pressed through the low-pressure body mounting frame 30, so that two independent spaces are formed. The high pressure area between the main plunger rod 17 and the auxiliary plunger rod 18 is connected in series in a flow path through a pipeline joint of an active check valve 31 and a passive check valve 32 to serve as a flow path for constant flow transfusion, and the low pressure area on the low pressure body 2 forms an independent loop through the pipeline joint and is used for lubricating the plunger rod, so that abrasion of the plunger rod and the high pressure sealing ring 28 and the low pressure sealing ring 29 in the moving process can be reduced.

The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Other technical features besides those described in the specification are known to those skilled in the art, and are not described herein in detail to highlight the innovative features of the present invention.

Claims

1. The liquid chromatographic pump is characterized by comprising a pump seat, a driving unit, a transmission unit, a plunger rod, a low-pressure body and a high-pressure body, wherein the driving unit, the transmission unit, the plunger rod, the low-pressure body and the high-pressure body are all arranged in the pump seat;

the support frame is also connected with a stabilizing mechanism.

2. The liquid chromatography pump according to claim 1, wherein a guide seat adapted to the transmission unit is provided in the pump seat, so that the transmission unit reciprocates in a straight line in the guide seat.

3. The liquid chromatography pump according to claim 2, wherein the transmission unit comprises a moving rod, a cam and a transmission shaft for mounting the cam, a guide hole for passing through the moving rod is arranged in the guide seat, and the moving rod is slidably connected with the guide hole through a sliding film.

4. A liquid chromatography pump according to claim 3, wherein the drive unit comprises a motor and pulleys mounted in the output shaft and the drive shaft of the motor, respectively, the two pulleys being connected by a belt.

5. The liquid chromatography pump according to claim 2, wherein the stabilizing mechanism comprises two pull pins arranged in the supporting frame and a connecting rod fixedly arranged in the end face of the guide seat, which is close to the side of the plunger rod, the connecting rods are in one-to-one correspondence with the pull pins, and a first spring is connected between the paired pull pins and the connecting rods and is in a stretching state;

6. The liquid chromatography pump according to claim 5, wherein the ball is connected with the bottom of the limit groove through a second spring, and the second spring is in a compressed state;

7. The liquid chromatography pump according to claim 6, wherein the low-pressure body is fixedly connected with the guide seat through guide rods, the number of the guide rods is four, and the area surrounded by the positions of the four guide rods in the guide seat is in a parallelogram shape;