CN219733574U - Plunger pump system and ion chromatograph - Google Patents

Abstract

The utility model relates to a plunger pump system, which is used for an ion chromatograph and comprises a first pump head and a second pump head, and the plunger pump system further comprises: a first gear; a second gear; a first rack; a second rack; the first gear can be respectively meshed with the first rack and the second rack, so that the rotation of the first gear can drive the plunger of the first pump head to move towards the suction position and drive the plunger of the second pump head to move towards the pumping position at the same time, the second gear can be respectively meshed with the first rack and the second rack, so that the rotation of the second gear can drive the plunger of the first pump head to move towards the pumping position and drive the plunger of the second pump head to move towards the suction position at the same time, and the first gear and the second gear are configured to asynchronously actuate the first rack and asynchronously actuate the second rack. The plunger pump system can enable the flow velocity of the fluid to be stable, has a simple structure and has a longer service life. The utility model also relates to an ion chromatograph.

Description

Plunger pump system and ion chromatograph

Technical Field

The utility model relates to the field of ion chromatography, in particular to a plunger pump system and an ion chromatograph.

Background

Ion chromatography (Ion Chromatography) is one of High Performance Liquid Chromatography (HPLC), a liquid chromatography method for analyzing anions and cations. Specifically, ion chromatography is a chromatography method in which a fixed relative ionic substance is separated with an ion exchange resin of low exchange capacity, and a change in the conductance of an effluent is continuously detected by a conductance detector.

Of the current ion chromatographs, the ICS-600 type ion chromatograph is based on ion chromatography technology and is designed specifically to meet the detection needs of the user's conventional anions and cations. The ion chromatograph is provided with a double-plunger pump, can be compatible with a micro-membrane inhibitor regenerated continuously through electrolysis or chemistry, is controlled through software, and has the advantages of simplicity in operation, rapidness in starting, reliability and stability in performance and the like.

The plunger pump is a key component in ion chromatographs, and is mainly used for injecting sample liquid into a rotary cut valve at a constant and customizable speed, and the rotary cut valve is configured to distribute the sample liquid into corresponding liquid pipelines in the ion chromatograph according to the flow path of an ICS system. For example, ICS-600 ion chromatographs employ a single motor, double-ended reciprocating plunger pump. In particular, a single motor is used to drive the two pump heads to reciprocate to achieve injection and flow control of the sample liquid. Compared with the traditional double-motor design, the single-motor double-head reciprocating plunger pump can reduce the volume and the size of an instrument to a smaller degree, thereby saving space and improving the overall efficiency of the system. In addition, by using only one motor to control the reciprocation of the two pump heads, the motion control system of the instrument is simplified. The design is simple and reliable, the number and complexity of components are reduced, and the stability and reliability of the system are improved.

As shown in fig. 3, the conventional single-motor double-head reciprocating plunger pump system 1 'has a two-stage structure mainly including a primary pump member F and a secondary pump member S, and the sample liquid pumped from the primary pump member F is fed into the secondary pump member S, and therefore, the two plunger pumps of the double-plunger pump system 1' are required to operate asynchronously.

In order to achieve the above-mentioned requirements of asynchronous movement, as shown in fig. 4, the above-mentioned primary pump member mainly includes a pump head F1, a push rod F2, a bearing F3, a support F4 and a spring F5, and the above-mentioned secondary pump member includes a reduction support S6, a reduction swing rod S7 and reduction bearings S8, S8' in addition to the pump head S1, the push rod S2, the bearing S3, the support S4 and the spring S5.

The cam C is connected with the driving motor and driven by the driving motor to swing reciprocally, so as to drive the two bearings F3 and S3 attached to the cam C to swing. The pump heads F1 and S1 are mainly used for sucking and discharging the sample liquid, and a check valve is provided in the pump heads to unidirectionally convey the sample liquid. The push rods F2, S2 are horizontally movable, and are connected at one end to the bearing and at the other end to the pump head to push the pump head to move by the thrust from the bearing. The bearings F3 and S3 are attached to the cam C and are driven by the cam C to swing left and right along the support. The supports F4 and S4 support the bearing to swing. The springs F5 and S5 are connected to the bearing via a link for pushing the push rod to return and for closely fitting the bearing to the cam. The deceleration support S6 is used for supporting the deceleration swinging rod S7. The deceleration pendulum rod S7 is used for transmitting thrust from the bearing S4, and one end is connected to the deceleration bearing S8, and the other end is connected to the deceleration bearing S8'. The speed reducing bearing S8' is connected to the push rod S2 so as to drive the pump head S1 to move via the push rod S2.

As can be seen from fig. 4, the cam C is driven by the driving motor as an initial power source, and transmits thrust to the push rods F2, S2 through the bearings F3, S3, thereby driving the push rods F2, S2 to reciprocate, and thus sucking and outputting the sample fluid.

However, in the case where the swing speed of the cam C is constant, the flow rate of the liquid pumped by the above-described plunger pump system is not constant throughout the process.

Taking the primary pump member as an example, at the initial position shown in fig. 4, the center of the cam C, the center of the bearing F3, the axis of the push rod F2, the contact point of the cam C with the bearing F3, and the contact point of the bearing F3 with the push rod F2 are all on the same horizontal line, at this time, the advancing speed of the cam C is completely transmitted to the push rod F2, and the moving speed of the push rod F2 is equal to the advancing speed of the cam C.

However, at the intermediate position shown in fig. 5, as the cam C swings rightward, the cam C pushes the bearing F3 rightward, and the bearing F3 swings rightward centering on the seat F4, thereby pushing the push rod F2 to move rightward. At this time, the center of the cam C, the center of the bearing F3, and the axis of the push rod F2 are not guaranteed to be on the same horizontal line, and the contact point of the cam C with the bearing F3 and the contact point of the bearing F3 with the push rod F2 are not guaranteed to be on the same horizontal line, and therefore, the speed of the push rod F2 moving in the horizontal direction is not equal to the advancing speed of the cam C in the horizontal direction, but is always in the process of being changed along with the swinging of the cam C, and thus the flow rate of the sample fluid cannot be kept constant.

In addition, since the plunger pump system adopts a two-stage transmission structure formed by a primary pump component and a secondary pump component, the secondary pump component also needs to comprise auxiliary mechanisms such as a speed reduction support S6, a speed reduction swing rod S7 and speed reduction bearings S8 and S8' in order to drive the secondary pump component to move. The addition of the auxiliary mechanisms not only can greatly increase the processing and manufacturing cost, but also can influence the transmission efficiency and the accuracy of the transmission mechanism, thereby negatively affecting the whole system.

In addition, as described above, after the cam C swings rightward to the maximum stroke, the push rod F2 is reset leftward, but the force that brings the push rod F2 to reset leftward is not from the cam C but from the spring F5. This requires that the spring force of the spring F5 is much greater than the urging force of the cam C to allow the cam C to closely engage the bearing F3, which can exert excessive pressure and friction on the cam surface, thereby causing undesirable wear on the cam C, affecting the service life.

Therefore, how to provide a plunger pump system with stable fluid flow rate, simple structure and long service life in the field of ion chromatography is a technical problem to be solved currently.

Disclosure of Invention

The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a plunger pump system that can always keep the flow rate of a pumped fluid constant, has a simple structure, and has a long service life.

In order to achieve the object of the present disclosure, there is provided a plunger pump system for an ion chromatograph including a first pump head and a second pump head, each pump head including a cylinder and a plunger located in the cylinder, the plunger being reciprocable between an inhalation position and a pumping position, the plunger pump system further comprising: a first gear that can be driven to rotate in a first direction; a second gear which is driven by the first gear to rotate in a second direction opposite to the first direction; the first rack is connected with the plunger of the first pump head so as to drive the plunger to reciprocate; the second rack is connected with the plunger of the second pump head so as to drive the plunger to reciprocate; the first gear can be respectively meshed with the first rack and the second rack, so that the rotation of the first gear can drive the plunger of the first pump head to move towards the suction position and drive the plunger of the second pump head to move towards the pumping position, the second gear can be respectively meshed with the first rack and the second rack, so that the rotation of the second gear can drive the plunger of the first pump head to move towards the pumping position and drive the plunger of the second pump head to move towards the suction position, and the first gear and the second gear are configured to asynchronously actuate the first rack and asynchronously actuate the second rack.

According to the structure, the plunger pump system only comprises a primary transmission structure, mainly a gear transmission structure, does not need a swing rod rotating structure and a speed reducing mechanism, has extremely high transmission precision, ensures that the flow velocity of a liquid sample in the ion chromatograph is kept stable, greatly reduces the complexity of the system, and simultaneously reduces the requirement on the installation space.

Preferably, the plunger pump system further includes an intermediate transmission device disposed between the first gear and the second gear along a gear transmission path for rotating the first gear and the second gear in opposite directions.

According to the above configuration, by providing an intermediate transmission between the first gear and the second gear, it is possible to improve the flexibility of transmission and control in which the first gear rotates the second gear, and also to provide more options in space, thereby enabling a more compact system arrangement (e.g., direct engagement between the first gear and the second gear is not necessarily required, thereby enabling a more flexible rack arrangement).

Preferably, the intermediate transmission device includes a third gear and a fourth gear that are directly meshed with each other, wherein the first gear rotates the third gear, and the fourth gear rotates the second gear.

According to the above constitution, by providing two intermediate transmission gears, the first gear and the second gear can be arranged at a distance, thereby allowing the arrangement of racks engaged therewith to be more flexible, and the drive control of the double-headed plunger to be more convenient.

Preferably, the third gear and the first gear are coaxially disposed so as to be non-rotatable and axially spaced apart, and the fourth gear and the second gear are coaxially disposed so as to be non-rotatable and axially spaced apart.

According to the above-described configuration, by arranging the third gear and the fourth gear that directly mesh with each other and the corresponding first gear and second gear coaxially spaced apart, it is possible to make the third gear and the fourth gear not interfere with meshing of the first gear, the second gear and their corresponding racks at any time, thereby making it easier for the first gear and the second gear to mesh with the same rack on both sides thereof, respectively.

Preferably, the plunger pump system further includes a first plunger and a second plunger, the first rack is connected to the plunger of the first pump head via the first plunger, and the second rack is connected to the plunger of the second pump head via the second plunger.

According to the above configuration, the first rack and the second rack can drive the plungers of the first pump head and the second pump head connected with the first rack and the second rack via the first push rod and the second push rod, respectively, so that the structure is simple and the operation is simple. In addition, due to the existence of the indirect push rod, the arrangement of the two pump heads can be more flexible, for example, the two pump heads are placed at a position with a distance from the gear and the rack, and therefore the flexibility of the system is improved. In addition, the possibility of controlling the gear drive to be asynchronous in time with the reciprocating movement of the plungers in the dual pump head can also be increased by providing additional components at the push rod position, for example by providing stops.

Preferably, the first gear and the second gear each include toothed portions and non-toothed portions, and are arranged such that their respective toothed portions alternately mesh with the first rack and with the second rack to achieve asynchronous reciprocating actuation.

According to the above configuration, the toothed portion and the non-toothed portion can be simply provided on the gear to realize asynchronous reciprocating movement of the rack engaged therewith. More specifically, when the toothed portion of the first gear is engaged with the rack to drive its rectilinear motion, the non-toothed portion of the second gear is in contact with the rack, so that it is achieved that only the first gear drives the rack, and vice versa.

Preferably, the angular range of the non-toothed portion is larger than the angular range of the toothed portion.

According to the above configuration, since the angular range of the non-toothed portion is larger than the angular range of the toothed portion, neither the first gear nor the second gear is engaged with the rack during a certain intermediate stage of the rotation process, and since no external force acts from the gears, the rack is slowly decelerated and then reversely moved before the rack is reversely moved by the next gear drive, whereby the entire movement process can be made smoother, and abrasion can be reduced and the service life can be prolonged.

Preferably, the first rack is a rack capable of meshing with the first gear and the second gear, and the second rack is a rack capable of meshing with the first gear and the second gear, respectively.

According to the above configuration, the first rack and the second rack are provided as a single rack, respectively, which can simplify the structure, simplify the installation, and reduce the manufacturing cost. Furthermore, by allowing the first gear and the second gear to asynchronously drive the same rack (e.g., two racks), the setup of the overall plunger pump system is greatly simplified.

Preferably, the first gear is disposed closer to the first pump head and the second pump head than the second gear.

According to the above configuration, by disposing the drive gear close to the two pump heads, the arrangement of the drive motor can be facilitated, thereby obtaining a more compact system.

Preferably, the first rack and the second rack are arranged parallel to each other, wherein the first rack, the first push rod and the plunger of the first pump head are positioned on a straight line, and the second rack, the second push rod and the plunger of the second pump head are also positioned on a straight line.

According to the above configuration, by arranging the rack, the plunger, and the rod, and the plunger of the pump head on a straight line, the power transmission efficiency can be improved, and the moving speed of the plunger can be made constant, and further the flow rate of the fluid can be made constant.

The utility model also relates to an ion chromatograph, comprising: the above-described plunger pump system; and a driving mechanism for driving the first gear to rotate.

According to the above configuration, the first gear is driven to rotate by the driving mechanism, and the entire plunger pump system is thereby driven to move, so that the rotational speed of the first gear can be kept constant while the rotational speed of the driving mechanism is kept constant, and the flow rate of the liquid can be kept constant.

Preferably, the plunger pump system further comprises a rotary cut valve, and in the pumping position, the first pump head or the second pump head is used for injecting sample liquid into the rotary cut valve, and the rotary cut valve is configured to dispense the sample liquid into a corresponding liquid pipeline in the ion chromatograph.

According to the above constitution, the rotary cut valve can realize stable distribution of the sample liquid by means of stable flow rate, thereby facilitating accurate operation of the ion chromatograph.

Drawings

Technical features of the present utility model are clearly described in the following technical solutions with reference to the above objects, and advantages thereof are apparent from the following detailed description with reference to the accompanying drawings, which illustrate preferred embodiments of the present utility model by way of example, without limiting the scope of the inventive concept.

Fig. 1 is a schematic diagram showing the overall structure of a plunger pump system for an ion chromatograph according to the present utility model.

Fig. 2A is a front view showing a gear set and a rack set of a plunger pump system for an ion chromatograph of the present utility model, fig. 2B is a perspective view from obliquely below, and fig. 2C is a schematic plan view from above.

Fig. 3 is a schematic diagram showing the overall structure of an ion chromatograph according to the related art.

Fig. 4 is a schematic diagram showing the overall structure of a single motor double-headed reciprocating plunger pump of the ion chromatograph of the prior art.

Fig. 5 is a schematic diagram showing the relative positions of a cam and a swing link in the neutral position of a single motor double-headed reciprocating plunger pump of a prior art ion chromatograph.

List of reference numerals:

1. 1' a plunger pump system;

11. a first pump head;

12. a second pump head;

13. a first push rod;

14. a second push rod;

a cylinder body B;

p plunger;

g1 A first gear;

g2 A second gear;

g3 A third gear;

g4 A fourth gear;

t1 is provided with a tooth part;

t2 has no teeth;

r1 is a first rack;

r2 is a second rack;

d1 A first direction;

d2 A second direction;

c cam;

a first stage pump member;

an S-stage pump member;

f1, S1 pump head;

f2, S2 pushing rods;

f3, S3 bearings;

f4, S4 support;

f5, S5 springs;

s6, a speed reduction support;

s7, decelerating the swing rod;

s8, S8' reducing bearings;

1A eluent supply means;

1B sample supply means;

a 1C separator;

1D a conductivity cell;

1E, a regeneration liquid recovery device;

a PS pressure sensor;

PD pulse damper;

a PA protection device;

and V sample injection valve.

Detailed Description

The present utility model relates to the field of ion chromatography, although the description is described with the aid of ion chromatography, it will be appreciated that the plunger pump system of the present utility model may also be applied to other systems comprising single motor asynchronous reciprocating double plungers, such as but not limited to other devices in the field of high performance liquid chromatography. Furthermore, while the plunger pump system of the present utility model includes a pump head, it should be understood that in actual products the pump head may be sold, packaged, transported, etc. separately from the other components of the plunger pump system, but should be incorporated into the plunger pump system during use of the ion chromatograph.

In the present utility model, the term "single motor" means that the plunger pump system as a whole is driven by a single driving motor; the term "dual plunger" means that the plunger pump system comprises two pump heads (plungers), both plungers being driven in motion by a single driving power; the term "reciprocating" means that the above-described drive motor drives two plungers to reciprocate back and forth in one direction; the term "asynchronous" means that the directions of movement of the two plungers are opposite, when one plunger performs an intake action, the other plunger performs a pumping action, and vice versa.

In the present utility model, the expression "along the gear transmission path" means along the power transmission path of the gear, for example, in the direction from the driving end to the driven end. In the present utility model, "gear", "rack" is a conventional understanding in the art unless otherwise specified, but these components may include other parts than conventional gears, racks, such as protrusions, stops, grooves, etc., to facilitate cooperation with other components or for control purposes, etc.

In the present utility model, the expressions "first", "second", etc. are not an order of importance of priority, but merely represent different individual devices, components, etc.

The plunger pump system of the present utility model is used for an ion chromatograph, as shown in fig. 3, which includes mainly a plunger pump system 1', an eluent supply device 1A, a sample supply device 1B, a separator 1C, a conductivity cell 1D, a regenerated liquid recovery device 1E, a sample injection valve V, and the like. The eluent flows as a mobile phase from the container containing the eluent of the eluent supply apparatus 1A to the plunger pump system 1', and the eluent having a stable flow rate after passing through the primary pump member F and the secondary pump member S in the plunger pump system 1' passes through, for example, the pressure sensor PS and the pulse damper PD to enter the sample valve V. At the same time, the sample liquid from the sample supply device 1B also flows into the sample valve V, and the sample valve V may be configured as a rotary cut valve, and the connection and disconnection of the flow of the sample fluid can be achieved by rotation. The eluent entering the sample valve V brings the sample liquid into the separator 1C (e.g. chromatographic column) via the protection device PA for separation. The eluent is ionized in the conductivity cell 1D, and then sent to the regeneration liquid storage tank of the regeneration liquid recovery device 1E, and then sent to the detector for detection.

The plunger pump system 1 of the present utility model comprises two pump heads, namely a first pump head 11 and a second pump head 12. Although not shown in detail in the figures, each pump head may also include other fluid components and control components that are not illustrated in detail. Each of the first pump head 11 and the second pump head 12 includes a cylinder B and a plunger P. The above-described plunger P moves between a suction position where the pump head sucks in fluid and a pump-out position where the pump head pumps out fluid, as shown in fig. 1, the plungers P of the first pump head 11 and the second pump head 12 are in an intermediate position (i.e., a position between the suction position and the pump-out position). Here, the position at which the plunger P moves to the leftmost side of the cylinder B may be defined as a suction position, and the position at which the plunger P moves to the rightmost side of the cylinder B may be defined as a pumping position, and the plunger P reciprocates back and forth between the suction position and the pumping position. It will be appreciated that when the plunger P is moved to the suction position, the plunger is already in a mode of sucking a liquid sample, and when the plunger P is moved to the pumping position, the plunger is already in a mode of pumping a liquid sample. In other words, the sample liquid is not sucked or pumped when the plunger is in the suction position or the pumping position.

To effect movement of the plunger in the pump head, the plunger pump system of the present utility model first includes a first gear, typically a drive gear, driven by a drive motor or other conceivable drive means (e.g., a hydraulic drive). Here, the rotation direction of the first gear is defined as a first direction D1, and a direction opposite to the first direction is defined as a second direction D2. Typically, during operation, the rotational direction of the first gear is maintained, i.e., the drive source (drive motor or other power mechanism) drives the first gear in one direction. In order to drive both pump heads simultaneously, the first gear needs to engage with two racks or rack portions, which will be described in further detail below. Since the rotation direction thereof remains unchanged, the first gear always drives one of the two racks to move in one direction, and always drives the other one to move in the other direction opposite to the one direction.

The above-described plunger pump system further includes a second gear independent of the first gear, and the second gear is not normally driven by the drive mechanism but is rotated by the first gear. Herein, the term "entraining" includes direct entraining and indirect entraining. Thus, the second gear may also be referred to as a driven gear. The second gear wheel also meshes with two racks or rack portions, which are described in detail below. Since the rotation direction of the second gear is opposite to that of the first gear, the second gear always drives one of the two racks to move in the other direction and always drives the other one of the two racks to move in the one direction.

Therefore, the rack can be driven to reciprocate back and forth by the first gear and the second gear, and then the plunger pump is driven to reciprocate back and forth.

Although an example in which the first rack and the second rack are single racks is disclosed in the present utility model, it should be understood that it is also possible to include a plurality of independent first rack portions or a plurality of independent second rack portions instead of a single rack. The first gear and the second gear may be engaged with different rack portions of the rack, respectively, and may be configured to cooperate with the control mechanism and the stopper mechanism, as long as the plunger can reciprocate back and forth.

The intermediate transmission device is not necessarily two gears that mesh with each other, and may be, for example, four or more gears that are arranged side by side with each other, as long as the mechanism is capable of achieving the reverse movement of the first gear and the second gear. In the present utility model, the intermediate transmission is typically a gear transmission, rather than a cam transmission, belt transmission, or the like, as described in the prior art.

A plunger pump system according to one embodiment of the present disclosure is described below with specific reference to fig. 1 to 2. Fig. 1 is a schematic diagram showing the overall structure of a plunger pump system 1 according to the present utility model.

As shown in fig. 1, the plunger pump system 1 of the present utility model mainly includes a first pump head 11, a second pump head 12, a first push rod 13, a second push rod 14, a gear set, and a rack set.

The first pump head 11 and the second pump head 12 each include a cylinder B and a plunger P positioned inside the cylinder B, and one ends of the plungers P of the first pump head 11 and the second pump head 12 are connected to the first push rod 13 and the second push rod 14, respectively, whereby the plungers P are configured to reciprocate between a suction position where liquid is sucked and a pumping position where liquid is pumped by an external force of the first push rod 13 and the second push rod 14 (fig. 1 shows a state where the plungers P are positioned at an intermediate position).

Hereinafter, a gear set and a rack set of the plunger pump system 1 for an ion chromatograph according to the present utility model will be specifically described with reference to fig. 2A to 2C. Fig. 2A is a front view showing a gear set and a rack set of the plunger pump system 1 for an ion chromatograph of the present utility model, fig. 2B is a perspective view, and fig. 2C is a schematic plan view.

As shown in fig. 2A, the gear set includes a first gear G1, a second gear G2, a third gear G3, and a fourth gear G4, the first gear G1 is driven to rotate in a first direction by a driving motor, the second gear G2 is driven to rotate in a second direction opposite to the first direction by the first gear G1, the third gear G3 and the fourth gear G4 constitute an intermediate transmission device, the intermediate transmission device is disposed between the first gear G1 and the second gear G2, the power of the first gear G1 is transmitted to the second gear G2, and the first gear G1 and the second gear G2 are rotated in opposite directions, specifically, the third gear G3 and the fourth gear G4 are engaged with each other, and the first gear G1 rotates the third gear G3, the third gear G3 transmits the power to the fourth gear G4 engaged therewith, and the fourth gear G4 rotates the fourth gear G2.

In order to achieve the above function, as shown more clearly in fig. 2B and 2C, the third gear G3 and the first gear G1 are arranged coaxially so as not to be rotatable relative to each other and so as to be spaced apart from each other in the axial direction of the gears, and likewise the fourth gear G4 and the second gear G2 are arranged coaxially so as not to be rotatable relative to each other and so as to be spaced apart from each other in the axial direction of the gears. It will be appreciated that the intermediate transmission of the present utility model may also comprise a gear train that is not coaxially disposed with either the first gear or the second gear, such as a plurality of gears disposed side by side as described above.

The rack set includes a first rack R1 and a second rack R2, wherein one end of the first rack R1 is connected to the first push rod 13 and is further connected to the plunger P of the first pump head 11, and one end of the second rack R2 is connected to the second push rod 14 and is further connected to the plunger P of the second pump head 12, whereby the plungers P of the first pump head 11 and the second pump head 12 are driven to move by the movements of the first rack R1 and the second rack R2.

Further, it is preferable that the first rack R1 and the second rack R2 are single racks engaged with the first gear G1 and the second gear G2, respectively. Here, the first gear and the second gear are usually engaged with different portions of the same rack, so as to avoid interference with each other. Thus, by providing the racks as a single rack, the structure can be simplified and the manufacturing cost can be reduced. It should also be appreciated that in other embodiments, the first gear engages a first one of the first racks and a first one of the second racks, and the second gear engages a second one of the first racks and a second one of the second racks, i.e., the first gear and the second gear may engage different ones of the racks.

The first gear G1 and the second gear G2 can be engaged with the first rack R1 and the second rack R2, respectively, so that the plungers P of the first pump head 11 and the second pump head 12 can be driven to move in opposite directions by rotation of the gears, specifically, since the first gear G1 and the second gear G2 are rotated in opposite directions, the first gear G1 and the second gear G2 are configured to be capable of asynchronously actuating the first rack R1 and capable of asynchronously actuating the second rack R2, rotation of the first gear G1 can simultaneously drive the plungers P of the first pump head 11 to the suction position and the plungers P of the second pump head 12 to the pumping position, and rotation of the first gear G2 can simultaneously drive the plungers P of the first pump head 11 to the pumping position and the plungers P of the second pump head 12 to the suction position.

In order to achieve the above-described asynchronous actuation function, there are various embodiments of the present utility model. In the embodiment shown in fig. 2A to 2C, the first gear G1 and the second gear G2 include a toothed portion T1 and an untoothed portion T2, respectively, and are provided such that their respective toothed portions T1 alternately mesh with the first rack R1 and the second rack R2, respectively. Further, the toothed portions T1 and the non-toothed portions T2 of the first gear G1 and the second gear G2 are positioned relative to the first rack R1 and the upper second rack R2 such that the toothed portions T1 of the first gear G1 and the toothed portions T1 of the second gear G2 do not simultaneously mesh with racks, whereby it is possible to prevent gear teeth from being broken due to the reverse rotation direction of the gears.

Preferably, the two non-toothed portions and the two toothed portions comprised by the first gear are angularly uniformly spaced apart, and the two non-toothed portions and the two toothed portions comprised by the second gear are also angularly uniformly spaced apart. More preferably, the angular range of the non-toothed portion T2 is larger than the angular range of the toothed portion T1. For example, the angular range of the non-toothed portion T2 may be 60-90 degrees, while the angular range of the toothed portion T1 may be 90-120 degrees.

In other embodiments, not shown, the first gear and the second gear are engaged with different rack portions, and when the first gear is engaged with its corresponding rack portion to drive it to move linearly, the second gear is not driven to move linearly despite being engaged with its corresponding rack portion by means of a stopper member or other control member, and then control is performed in the opposite direction. In these embodiments, the first gear and the second gear may be configured as full teeth, i.e., not include non-toothed portions. But this is not preferred because even though the transmission is also stable, more additional mechanisms are required to control the order of the asynchronous transmissions.

As shown in fig. 1, fig. 1 shows an example in which the first gear G1 is arranged closer to the first pump head 11 and the second pump head 12 than the second gear G2, and the first gear G1 rotates in a counterclockwise direction, and the second gear rotates in a clockwise direction.

During the rotation, at the start time, the toothed portion T1 of the first gear G1 is engaged with the first rack R1 and the second rack R2, the toothed portion T1 of the second gear G2 is not engaged with the first rack R1 and the second rack R2, and the first rack R1 moves in the left direction and the second rack R2 moves in the right direction under the driving of the first gear G1.

With the rotation of the first gear G1, the toothed portion T1 of the first gear G1 is disengaged from the rack during a certain period of time in the middle, and at this time, since the angular range of the non-toothed portion T2 is larger than the angular range of the toothed portion T1, neither the first gear G1 nor the second gear G2 is engaged with the first rack R1 nor the second rack R2 during a certain period of time, and the movement of the rack starts to be decelerated without the action of external force.

After a certain time has elapsed, the toothed portion T1 of the second gear G2 starts to mesh with the rack, thereby driving the rack to move in the opposite direction.

The above-mentioned movement process is repeatedly performed, and only the first gear G1 is driven to rotate in a constant direction by the driving motor, so that the first rack R1 and the second rack R2 can be driven to reciprocate asynchronously. In addition, by setting the angular range without the toothed portion T2 to be larger than the angular range of the toothed portion T1 described above, the rack can be decelerated before each reverse movement, so that the movement process can be made smoother, the loss can be reduced, and the service life can be prolonged.

As shown in fig. 1, the first rack R1 and the second rack R2 are arranged parallel to each other, and the first rack R1, the first push rod 13, and the plunger P of the first pump head 11 are aligned, and the second rack R2, the second push rod 13, and the plunger P of the second pump head 12 are also aligned.

Accordingly, the moving speeds of the first rack R1 and the second rack R2 can be transmitted to the first pump head 11 and the second pump head 12 without loss, respectively, and the flow rate of the fluid can be kept stable. It will be appreciated that the present utility model may be provided with other transmission mechanisms between the rack and the plunger than a push rod, such as a four bar linkage or the like.

As shown in fig. 1, the plunger pump system 1 of the present utility model described above is applied to the ion chromatograph shown in fig. 1 instead of the conventional single-motor double-head reciprocating plunger pump system, and the plunger pump system 1 of the present utility model has a single-stage transmission structure, and can simplify the processing and assembling procedure, and simplify the structure, and further, by setting the speed of the driving structure to be constant, the moving speed of the rack can be kept constant all the time, so that the moving speed of the plunger can be kept constant, and further, the flow rate of the liquid can be kept stable.

The foregoing description has provided numerous features and advantages including various alternative embodiments, as well as details of the structure and function of the devices and methods. The intent herein is exemplary and not exhaustive or limiting.

It will be apparent to those skilled in the art that various modifications can be made in the full scope indicated by the broad general meaning of the terms expressed in the appended claims, especially in matters of structure, material, elements, components, shapes, sizes and arrangements of parts, including combinations of parts within the principles described herein. To the extent that such modifications do not depart from the spirit and scope of the appended claims, they are intended to be included therein.

Claims (12)

1. A plunger pump system (1), the plunger pump system (1) being for an ion chromatograph, comprising a first pump head (11) and a second pump head (12), each pump head comprising a cylinder (B) and a plunger (P) located within the cylinder (B), the plunger (P) being reciprocally movable between an inhalation position and a pumping position, characterized in that the plunger pump system (1) further comprises:

a first gear (G1), the first gear (G1) being drivable to rotate in a first direction;

-a second gear (G2), said second gear (G2) being drivable by said first gear (G1) to rotate in a second direction opposite to said first direction;

a first rack (R1), wherein the first rack (R1) is connected with a plunger (P) of the first pump head (11) so as to drive the plunger to reciprocate; and

a second rack (R2), the second rack (R2) being connected to a plunger (P) of the second pump head (12) so as to be capable of driving it to reciprocate;

wherein,,

the first gear (G1) can be respectively meshed with the first rack (R1) and the second rack (R2), so that the rotation of the first gear (G1) can simultaneously drive the plunger (P) of the first pump head (11) to move towards the suction position and drive the plunger (P) of the second pump head (12) to move towards the pumping position;

the second gear (G2) can be respectively meshed with the first rack (R1) and the second rack (R2), so that the rotation of the second gear (G2) can simultaneously drive the plunger (P) of the first pump head (11) to move towards a pumping position and drive the plunger (P) of the second pump head (12) to move towards a suction position;

the first gear (G1) and the second gear (G2) are configured to asynchronously actuate the first rack (R1) and to asynchronously actuate the second rack (R2).

2. Plunger pump system (1) according to claim 1, further comprising an intermediate transmission arranged between the first gear (G1) and the second gear (G2) along a gear transmission path for rotating the first gear (G1) and the second gear (G2) in opposite directions.

3. The plunger pump system (1) as claimed in claim 2, wherein the intermediate transmission comprises a third gear (G3) and a fourth gear (G4) which are directly engaged with each other, wherein the first gear (G1) rotates the third gear (G3), and the fourth gear (G4) rotates the second gear (G2).

4. A plunger pump system (1) as claimed in claim 3, characterized in that the third gear (G3) is coaxially arranged non-rotatably and axially spaced apart from the first gear (G1), and the fourth gear (G4) is coaxially arranged non-rotatably and axially spaced apart from the second gear (G2).

5. The plunger pump system (1) as claimed in claim 1, further comprising a first push rod (13) and a second push rod (14), the first rack (R1) being connected to the plunger (P) of the first pump head (11) via the first push rod (13), and the second rack (R2) being connected to the plunger (P) of the second pump head (12) via the second push rod (14).

6. Plunger pump system (1) according to any one of claims 1 to 5, wherein the first gear (G1) and the second gear (G2) each comprise a toothed portion (T1) and a non-toothed portion (T2), and are arranged such that their respective toothed portions (T1) are alternately engaged with the first rack (R1) and with the second rack (R2) to achieve asynchronous reciprocating movement of the first rack (R1) and the second rack (R2).

7. Plunger pump system (1) according to claim 6, characterized in that the angular range of the non-toothed portion (T2) is larger than the angular range of the toothed portion (T1).

8. The plunger pump system (1) as set forth in claim 6, wherein the first rack (R1) is one rack capable of meshing with the first gear (G1) and the second gear (G2), respectively, and the second rack (R2) is one rack capable of meshing with the first gear (G1) and the second gear (G2), respectively.

9. Plunger pump system (1) according to any one of claims 1 to 5, wherein the first gear (G1) is arranged closer to the first pump head (11) and the second pump head (12) than the second gear (G2).

10. Plunger pump system (1) according to claim 5, characterized in that the first rack (R1) and the second rack (R2) are arranged parallel to each other, wherein the first rack (R1), the first push rod (13) and the plunger (P) of the first pump head (11) are located in a straight line, and the second rack (R2), the second push rod (14) and the plunger (P) of the second pump head (12) are also located in a straight line.

11. An ion chromatograph, characterized in that the ion chromatograph comprises:

plunger pump system (1) according to any one of claims 1 to 10; and

and the driving mechanism is used for driving the first gear (G1) to rotate.

12. The ion chromatograph of claim 11, further comprising a rotary cut valve, in the pump-out position, the first pump head (11) or the second pump head (12) being configured to inject a sample liquid into the rotary cut valve, the rotary cut valve being configured to dispense the sample liquid into a corresponding liquid line in the ion chromatograph.