CN114487213A - Volumetric liquid chromatograph flow measuring device and method - Google Patents
Volumetric liquid chromatograph flow measuring device and method Download PDFInfo
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- 238000012625 in-situ measurement Methods 0.000 abstract description 4
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- 238000000926 separation method Methods 0.000 description 15
- 238000012360 testing method Methods 0.000 description 7
- 238000004704 ultra performance liquid chromatography Methods 0.000 description 4
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F11/00—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it
- G01F11/02—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement
- G01F11/021—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the piston type
- G01F11/025—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the piston type with manually operated pistons
- G01F11/027—Apparatus requiring external operation adapted at each repeated and identical operation to measure and separate a predetermined volume of fluid or fluent solid material from a supply or container, without regard to weight, and to deliver it with measuring chambers which expand or contract during measurement of the piston type with manually operated pistons of the syringe type
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/16—Injection
- G01N30/20—Injection using a sampling valve
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/26—Conditioning of the fluid carrier; Flow patterns
- G01N30/28—Control of physical parameters of the fluid carrier
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/04—Preparation or injection of sample to be analysed
- G01N30/16—Injection
- G01N30/20—Injection using a sampling valve
- G01N2030/201—Injection using a sampling valve multiport valves, i.e. having more than two ports
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
- G01N30/02—Column chromatography
- G01N30/26—Conditioning of the fluid carrier; Flow patterns
- G01N30/28—Control of physical parameters of the fluid carrier
- G01N30/32—Control of physical parameters of the fluid carrier of pressure or speed
- G01N2030/326—Control of physical parameters of the fluid carrier of pressure or speed pumps
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Abstract
The invention discloses a flow measuring device and a method for a positive displacement liquid chromatograph, which comprises a workbench, a liquid inlet pipe, a first electromagnetic valve, a three-way valve, a second electromagnetic valve, a liquid outlet pipe, an injector, a controller, a trigger switch unit and a sliding counterweight mechanism, wherein the injector comprises an injector pipe and a push rod, the sliding counterweight mechanism comprises a linear guide rail, a sliding block and a counterweight block, the linear guide rail is fixedly arranged on the workbench, the table top of the workbench is vertical to the gravity direction, and an included angle is formed between the linear guide rail and the table top of the workbench; the sliding block is arranged on the linear guide rail and is in sliding connection with the linear guide rail; the balancing weight is fixedly arranged on the sliding block; the sliding block is connected with the tail part of the push rod through a transmission mechanism. Constant tension is provided through the sliding counterweight mechanism, and the tension does not change along with the sliding stroke, so that the constant pressure in the injector is ensured, and the in-situ measurement of the HPLC flow is realized.
Description
Technical Field
The invention relates to a device and a method for measuring the flow of a liquid chromatograph, which adopt a volume type principle and can be applied to the measurement of the flow index of the liquid chromatograph used in the industries of food, medicine, environment, chemical industry, scientific research and the like.
Background
Liquid Chromatograph (HPLC) is a commonly used instrument for organic analysis, and is widely applied to industries such as food, medicine, environment, chemical industry, scientific research and the like. The liquid chromatograph consists of four parts of transfusion, separation, detection and data processing. Wherein the infusion system (hereinafter referred to as pump) is the "heart" of the HPLC and provides the power for the operation of the HPLC. The most critical parameter for pump metering is flow. The accuracy and stability of the pump flow rate is directly related to the consistency and effectiveness of the HPLC measurement results. At present, a great deal of Ultra Performance Liquid Chromatography (UPLC) instruments emerge, and the UPLC has the important characteristic that the pump flow is set to be below 0.2mL/min for operation, and the requirement of in-situ measurement of a liquid chromatograph is provided, namely the pump flow is accurately measured under a certain pressure state, and the accuracy and the stability of the flow under the pump working state of the in-situ measurement UPLC are realized. At the present stage, the technical standards of the HPLC measurement calibration work are mainly JJG705-2014 "calibration procedure of liquid chromatograph" and european medicine administration quality control laboratory (EDQM-OMCL) "quality control document", and the flow measurement is performed by adopting a manual weighing and calculating mode, so that the method cannot meet the requirement of HPLC low-flow in-situ field measurement. The existing flowmeter can not realize the in-situ measurement of flow in function.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the defect that the existing flowmeter is not suitable for the inspection of flow related indexes of a liquid chromatograph, the invention provides a device and a method for measuring the flow of a positive displacement liquid chromatograph.
The technical scheme is as follows: in order to achieve the purpose, the invention adopts the technical scheme that:
the utility model provides a positive displacement liquid chromatograph flow measurement device, includes workstation, feed liquor pipe, solenoid valve one, tee bend, solenoid valve two, drain pipe, syringe, controller, trigger switch unit, slip counter weight mechanism, wherein:
one end of the electromagnetic valve is connected with the liquid inlet pipe, and the other end of the electromagnetic valve is connected with the first pipe orifice of the tee joint. One end of the second electromagnetic valve is connected with the liquid outlet pipe, and the other end of the second electromagnetic valve is connected with a pipe orifice two of the tee joint. And the injector port of the injector is connected with the three-way pipe port III.
The injector comprises an injector tube and a push rod, the injector tube is fixedly arranged on the workbench, the head of the push rod is arranged in the injector tube, and the push rod is connected with the injector tube in a sliding manner.
The trigger switch unit comprises a trigger head I, a trigger head II and a trigger separation blade, wherein the trigger head I and the trigger head II are electrically connected with a controller, and a timer is arranged in the controller. One end of the trigger separation blade is fixedly connected with the tail of the push rod, and the first trigger head and the second trigger head are located on a stroke track of the trigger separation blade.
The sliding counterweight mechanism comprises a linear guide rail, a sliding block and a counterweight block, the linear guide rail is fixedly installed on the workbench, the table surface of the workbench is perpendicular to the gravity direction, and an included angle is formed between the linear guide rail and the table surface of the workbench. The slider is installed on linear guide, just slider and linear guide sliding connection. The balancing weight is fixedly installed on the sliding block. The sliding block is in driving connection with the tail part of the push rod.
When the push rod is located at the first limit position, the trigger blocking piece is in contact with the first trigger head, the sliding block is located at the first limit position, and the timer counts time. When the push rod is located at the second limit position, the triggering separation blade is in contact with the triggering head II, the sliding block is located at the second limit position, and the timer counts time II.
When the push rod is loosened, when the sliding block is located at the third limit position, the triggering separation blade is in contact with the third triggering head, and at the moment, the push rod is located at the third limit position. When the sliding block is located at the second limit position, the triggering separation blade is in contact with the second triggering head, and the push rod is located at the second limit position. When the sliding block is located at the second limit position, the triggering blocking piece is in contact with the first triggering head, and the push rod is located at the first limit position.
Preferably: including fixed pulley, rope one end and the afterbody fixed connection of push rod, the other end is walked around fixed pulley and balancing weight fixed connection.
Preferably: the push rod comprises a connecting rod, wherein one end of the connecting rod is fixedly connected with the sliding block, and the other end of the connecting rod is fixedly connected with the tail part of the push rod.
Preferably: the counterweight fixing device comprises a counterweight fixing screw rod and a counterweight block locking nut, wherein the counterweight fixing screw rod is fixedly installed on a sliding block, the counterweight block is arranged on the counterweight fixing screw rod, and the counterweight block is fixed with the counterweight fixing screw rod through the counterweight block locking nut.
Preferably: the linear guide rail is vertical to the table surface of the workbench.
Preferably: a temperature sensor is arranged on the syringe tube.
Preferably: the trigger separation blade is fixed on the tail part of the push rod through the matching of a fixing screw and a fixing nut.
Preferably: the trigger switch unit comprises a third trigger head, the third trigger head is electrically connected with the controller, and the third trigger head is located on a stroke track of the trigger separation blade.
A flow measuring method of a positive displacement liquid chromatograph comprises the following steps:
the first electromagnetic valve is opened, the second electromagnetic valve is closed, and the liquid enters the injector through the liquid inlet pipe and the tee joint. The push rod in the injector is pushed out under the action of liquid pressure, the push rod drives the trigger separation blade to move, the trigger separation blade passes through the trigger head one time, the trigger separation blade is contacted with the trigger head one time, the timer starts to work, and the timer times the first time
While recording the volume one
. Meanwhile, the push rod drives the sliding block to slide upwards along the linear guide rail, and drives the balancing weight to lift along the direction opposite to the gravity, so that the balancing weight provides resistance in the opposite direction to the push rod.
The liquid continues to enter the injector, the push rod in the injector continues to be pushed out under the action of the liquid pressure, the push rod continues to drive the trigger separation blade to move, when the trigger separation blade passes through the second trigger head, the trigger separation blade is contacted with the second trigger head, and the timer times the second trigger head
Simultaneously recording the volume two
。
The unit flow rate is:
wherein:
the flow rate is expressed in terms of a unit flow rate,
indicating the volume of the effective stroke of the plunger within the syringe barrel,
and the running time of the trigger barrier between the first trigger head and the second trigger head is shown.
Preferably: the volume of the active stroke of the plunger in the syringe barrel is calibrated as follows:
setting two time timing programs which are respectively recorded as a first time timing program and a second time timing program, wherein the first time timing program is used for recording the running time of the trigger barrier between the first trigger head and the second trigger head
，
. The second time timer is used for recording the total time of multiple circulation measurement
。
To carry out
Measuring in a second continuous cycle, measuring the first time in a timing sequence
The running times of the secondary measurements, respectively
. At the total time
The liquid flowing out from the liquid outlet is introduced into the container through a pipeline, and the net weight of the container before the liquid is received is respectively measured
And total weight after receiving liquid
Then the effective stroke volume of the push rod in the syringe tube is:
wherein,
indicating the volume of the effective stroke of the plunger within the syringe barrel,
indicating temperature
The density of the liquid to be treated,
and indicating the time delay correction introduced in the communication process of the second electromagnetic valve.
Compared with the prior art, the invention has the following beneficial effects:
1. the constant-pressure liquid chromatograph flow measurement device has the advantages that constant-pressure drive is provided through the sliding counterweight mechanism, the constant-pressure effect is more stable, the pressure range covers (10-600) bar, and further the lower limit of flow measurement is lower than 0.001 ml/min.
2. The mode of current counter weight scheme and fixed knot structure for trigger switch unit is more stable, is difficult for producing the displacement in transportation and removal process, and stability data show, and current compound mode makes flow test data can remain stable in 12 months, has consequently reduced the device calibration number of times, changes in the use.
3. By introducing the time delay correction parameter of the electromagnetic valve, a test result shows that the flow measurement result after time delay correction has better linearity.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Fig. 2 is a schematic diagram of a connection for measuring traffic according to an embodiment of the present invention.
Detailed Description
The present invention is further illustrated by the following description in conjunction with the accompanying drawings and the specific embodiments, it is to be understood that these examples are given solely for the purpose of illustration and are not intended as a definition of the limits of the invention, since various equivalent modifications will occur to those skilled in the art upon reading the present invention and fall within the limits of the appended claims.
A flow measuring device of a positive displacement liquid chromatograph is shown in figure 1 and comprises a workbench, a liquid inlet pipe 20, a first electromagnetic valve 31, a tee joint 1, a second electromagnetic valve 32, a liquid outlet pipe 21, an injector 4, a controller 5, a trigger switch unit 6, a sliding counterweight mechanism, a fixed pulley 74 and a cable 75, wherein:
one end of the first electromagnetic valve 31 is connected with the liquid inlet pipe 20, and the other end of the first electromagnetic valve is connected with the first pipe orifice of the tee joint 1. One end of the second electromagnetic valve 32 is connected with the liquid outlet pipe 21, and the other end of the second electromagnetic valve is connected with the second pipe orifice of the tee 1. And the injector opening of the injector 4 is connected with the pipe opening III of the tee joint 1.
The injector 4 comprises a syringe tube 41 and a push rod 42, the syringe tube 41 is fixedly arranged on a workbench, the head of the push rod 42 is arranged in the syringe tube 41, and the push rod 42 is connected with the syringe tube 41 in a sliding way. The syringe barrel 41 is provided with a temperature sensor 8. The heat capacity of the probe part of the temperature sensor is small, the probe part is tightly attached to the outer wall of the re-injector, the temperature of the measuring system can be sensed quickly, a heat preservation device can be added outside the injector, and the interference of the external environment to the temperature is reduced.
The trigger switch unit 6 comprises a first trigger head 61, a second trigger head 62, a third trigger head 63 and a trigger blocking sheet 64, wherein the first trigger head 61, the second trigger head 62 and the third trigger head 63 are electrically connected with the controller 5, and a timer is arranged in the controller 5. One end of the trigger block 64 is fixedly connected to the tail portion of the push rod 42, and in another embodiment of the present invention, the trigger block 64 is fixed to the tail portion of the push rod 42 by the cooperation of the fixing screw 43 and the fixing nut 44. And the first trigger head 61, the second trigger head 62 and the third trigger head 63 are positioned on the stroke track of the trigger blocking sheet 64.
The sliding counterweight mechanism comprises a linear guide rail 71, a sliding block 72 and a counterweight block 73, wherein the linear guide rail 71 is fixedly installed on the workbench, the table surface of the workbench is perpendicular to the gravity direction, an included angle is formed between the table surface of the linear guide rail 71 and the table surface of the workbench, and the gravity of the counterweight block 73 cannot be completely offset as long as the included angle is formed between the table surface of the linear guide rail 71 and the table surface of the workbench. In another embodiment of the invention, the linear guide 71 is perpendicular to the table top of the table. The slider 72 is mounted on the linear guide 71, and the slider 72 is slidably connected with the linear guide 71. The weight 73 is fixedly mounted on the slider 72. In another embodiment of the present invention, the counterweight fixing screw 76 and the counterweight block locking nut 77 are included, the counterweight fixing screw 76 is fixedly installed on the sliding block 72, the counterweight block 73 is disposed on the counterweight fixing screw 76, and the counterweight block 73 is fixed with the counterweight fixing screw 76 through the counterweight block locking nut 77. Different pulling forces can be provided by adjusting the number and weight of the clump weights. Thereby realize the inside different pressures of syringe to realize the normal position detection of different pressure demands. The slider 72 is connected with the tail part of the push rod 42 through a transmission mechanism. The transmission mechanism comprises a fixed pulley 74 and a cable 75, one end of the cable 75 is fixedly connected with the tail part of the push rod 42, the other end of the cable is fixedly connected with the balancing weight 73 by bypassing the fixed pulley 74, the opening of the injector 4 faces upwards, the tail part of the push rod 42 is positioned below the opening of the injector 4, and the gravity of the balancing weight 73 is subjected to direction conversion through the fixed pulley and acts on the tail part of the push rod 42. In another embodiment of the present invention, the transmission mechanism includes a connecting rod, one end of the connecting rod is fixedly connected to the sliding block 72, the other end of the connecting rod is fixedly connected to the tail portion of the pushing rod 42, the injector opening of the injector 4 faces downward, the tail portion of the pushing rod 42 is located above the injector opening of the injector 4, and the connecting rod converts the gravity of the counterweight block 73 to act on the tail portion of the pushing rod 42.
The working principle is as follows: when the first electromagnetic valve 31 is opened and the second electromagnetic valve 32 is closed, the liquid is injected into the syringe tube 41, the push rod is pushed to move downwards, the counterweight block 73 is driven to move upwards, when the push rod 42 is located at the first limit position, the trigger blocking piece 64 is in contact with the first trigger head 61, at this time, the slide block 72 is located at the first limit position, and the timer counts time by one. When the push rod 42 is located at the second limit position, the trigger block 64 contacts the second trigger head 62, and the slide block 72 is located at the second limit position, and the timer counts time two. When the push rod 42 is located at the third limit position, the trigger block 64 contacts the trigger head three 63, and the slide block 72 is located at the third limit position, and the timer counts three.
When the second electromagnetic valve 32 is opened, the counterweight block 73 moves downwards to drive the push rod to move upwards, the liquid injected into the syringe tube 41 flows out of the liquid outlet tube 21, when the slider 72 is located at the third limit position, the trigger blocking piece 64 contacts with the trigger head third 63, and at this time, the push rod 42 is located at the third limit position. When the slider 72 is in the second extreme position, the trigger block 64 contacts the second trigger head 62, and the push rod 42 is in the second extreme position. When the slide block 72 is located at the second extreme position, the trigger blocking piece 64 is in contact with the first trigger head 61, and the push rod 42 is located at the first extreme position.
A flow measuring method of a positive displacement liquid chromatograph comprises the following steps:
The liquid continuously enters the injector 4, the push rod 42 in the injector 4 is continuously pushed out under the action of the liquid pressure, the push rod 42 continuously drives the trigger blocking piece 64 to move, when the trigger blocking piece 64 passes through the second trigger head 62, the trigger blocking piece 64 is contacted with the second trigger head 62, and the timer times for the second time
Simultaneously recording the volume two
。
Liquid continuously enters the injector 4, the push rod 42 in the injector 4 is continuously pushed out under the action of liquid pressure, the push rod 42 continuously drives the trigger block piece 64 to move, when the trigger block piece 64 passes through the trigger head III 63, the trigger block piece 64 is contacted with the trigger head III 63, and the timer times III
Simultaneously recording volume three
。
The electromagnetic valve, the trigger switch and the temperature sensor are connected to the host controller through cables. The trigger sequence of the trigger switch can be trigger head one-trigger head two, trigger head two-trigger head three, trigger head one-trigger head three.
The unit flow rate is:
wherein:
and means the flow rate per unit flow, i.e. flow rate,
indicating the volume of the effective stroke of the plunger within the syringe barrel,
indicating the time of travel of the trigger blade 64 between the first 61 and second 62 trigger heads.
Step 2, the second electromagnetic valve 32 is opened, at this time, the liquid outlet pipe 21 is conducted, the balancing weight 73 slides downwards along the linear guide rail 71 under the action of gravity, so that the balancing weight 73 provides an upward thrust for the push rod 42, therefore, the liquid in the injector 4 is pushed out by the push rod 42, the liquid flows out through the second pipe orifice of the tee joint 1 and the liquid outlet pipe 21, when the front end of the push rod rebounds to the bottom, the next work can be carried out, and after all the works are completed, the second electromagnetic valve 32 is closed.
The constant pulling force is provided by the counterweight drive in the whole sliding process, and the pulling force does not change along with the sliding stroke. The force applied to the end of the push rod is also constant, thereby ensuring a constant pressure inside the syringe.
The volume of active stroke of the plunger in the syringe barrel is calibrated as follows:
setting two time timing programs, namely a first time timing program and a second time timing program, wherein the first time timing program is used for recording the contact of the trigger baffle plate 64 on the trigger head I61Run time between two hairs 62
，
. The second time timer is used for recording the total time of multiple circulation measurement
。
To proceed with
Measuring in a second continuous cycle, measuring the first time in a timing sequence
The running times of the secondary measurements, respectively
. At the total time
The liquid flowing out from the liquid outlet is introduced into the container through a pipeline, and the net weight of the container before the liquid is received is respectively measured
And total weight after receiving liquid
Then the volume of the effective stroke of pushrod 42 within syringe barrel 41 is:
wherein,
indicating the effectiveness of the plunger in the syringe barrelThe volume of the stroke is such that,
indicating temperature
The density of the liquid to be treated,
and indicating the time delay correction introduced in the communication process of the second electromagnetic valve. The time delay correction value introduced in the electromagnetic valve switch action communication process is between 5 and 20 ms.
TABLE 1 delay corrected flow measurements
As shown in table 1, the flow measurement result after the delay correction is better in linearity and higher in accuracy. The invention not only meets the measurement of the flow index of the common high performance liquid chromatograph, but also meets the measurement requirement of the ultra-high performance liquid chromatograph and the liquid chromatograph-mass spectrometer on the flow in the ultra-low range, and the measurement repeatability is obviously superior to the prior art.
TABLE 21.0 Long-term stability data for ml/min flow rates
As shown in table 2, the prior art combination makes the flow test data stable for 12 months, thereby reducing the number of times the device is calibrated and making it easier to use.
TABLE 3 introduction of solenoid valve delay correction parameter test results
As shown in table 3, by introducing the solenoid valve delay correction parameter, the test result shows that the flow measurement result after delay correction has better linearity and higher precision.
The invention significantly reduces the boot-strap balancing time of the device by two measures: 1, the addition of the counterweight shortens the test recovery time, and a diaphragm valve can be used, so that the dead volume of the whole measuring system is smaller. 2 is to add a temperature sensor which can sense the temperature equilibrium state of the measuring system and add a thermal isolation measure to reduce the heat exchange between the external environment and the injector. Compared with the prior art, the startup balance time of the device is obviously reduced by less than 2min, so that the test is more efficient.
The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.
Claims (10)
1. A flow measuring device of a positive displacement liquid chromatograph is characterized in that: including workstation, feed liquor pipe (20), solenoid valve (31), tee bend (1), solenoid valve two (32), drain pipe (21), syringe (4), controller (5), trigger switch unit (6), slip counter weight mechanism, wherein:
one end of the first electromagnetic valve (31) is connected with the liquid inlet pipe (20), and the other end of the first electromagnetic valve is connected with a pipe orifice I of the tee joint (1); one end of the second electromagnetic valve (32) is connected with the liquid outlet pipe (21), and the other end of the second electromagnetic valve is connected with a pipe orifice II of the tee joint (1); the injector opening of the injector (4) is connected with the pipe opening III of the tee joint (1);
the injector (4) comprises an injector tube (41) and a push rod (42), the injector tube (41) is fixedly arranged on the workbench, the head of the push rod (42) is arranged in the injector tube (41), and the push rod (42) is connected with the injector tube (41) in a sliding manner;
the trigger switch unit (6) comprises a first trigger head (61), a second trigger head (62) and a trigger blocking piece (64), the first trigger head (61) and the second trigger head (62) are electrically connected with the controller (5), and a timer is arranged in the controller (5); one end of the trigger blocking piece (64) is fixedly connected with the tail part of the push rod (42), and the first trigger head (61) and the second trigger head (62) are positioned on a stroke track of the trigger blocking piece (64);
the sliding counterweight mechanism comprises a linear guide rail (71), a sliding block (72) and a counterweight block (73), the linear guide rail (71) is fixedly arranged on the workbench, the table surface of the workbench is vertical to the gravity direction, and an included angle is formed between the linear guide rail (71) and the table surface of the workbench; the sliding block (72) is arranged on the linear guide rail (71), and the sliding block (72) is connected with the linear guide rail (71) in a sliding manner; the balancing weight (73) is fixedly arranged on the sliding block (72); the sliding block (72) is connected with the tail part of the push rod (42) through a transmission mechanism;
when the push rod (42) is located at a first limit position, the trigger blocking piece (64) is in contact with a first trigger head (61), the sliding block (72) is located at a first limit position, and a timer counts time for one; when the push rod (42) is located at the second limit position, the trigger blocking piece (64) is in contact with the second trigger head (62), the sliding block (72) is located at the second limit position, and the timer counts time by the second limit position.
2. The flow rate measuring device for a positive displacement liquid chromatograph according to claim 1, wherein: the transmission mechanism comprises a fixed pulley (74) and a rope (75), one end of the rope (75) is fixedly connected with the tail part of the push rod (42), the other end of the rope (75) bypasses the fixed pulley (74) to be fixedly connected with a balancing weight (73), the injector opening of the injector (4) faces upwards, and the tail part of the push rod (42) is positioned below the injector opening of the injector (4); or the transmission mechanism comprises a connecting rod, one end of the connecting rod is fixedly connected with the sliding block (72), the other end of the connecting rod is fixedly connected with the tail part of the push rod (42), the injector opening of the injector (4) faces downwards, and the tail part of the push rod (42) is positioned above the injector opening of the injector (4).
3. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 2, wherein: including counter weight fixing screw (76), balancing weight lock nut (77), counter weight fixing screw (76) fixed mounting is on slider (72), balancing weight (73) set up on counter weight fixing screw (76), just balancing weight (73) are fixed mutually with counter weight fixing screw (76) through balancing weight lock nut (77).
4. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 3, wherein: and a diaphragm valve is arranged at the joint of the injector opening of the injector (4) and the pipe opening III of the tee joint (1).
5. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 4, wherein: the linear guide rail (71) is vertical to the table surface of the workbench.
6. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 5, wherein: a temperature sensor (8) is arranged on the syringe tube (41).
7. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 6, wherein: the trigger baffle plate (64) is fixed on the tail part of the push rod (42) through the matching of a fixing screw (43) and a fixing nut (44).
8. The apparatus for measuring the flow rate of a positive displacement liquid chromatograph according to claim 7, wherein: the trigger switch unit (6) comprises a trigger head III (63), the trigger head III (63) is electrically connected with the controller (5), and the trigger head III (63) is located on a stroke track of the trigger blocking sheet (64).
9. A flow rate measuring method based on the flow rate measuring apparatus for a positive displacement liquid chromatograph according to claim 1, comprising the steps of:
the first electromagnetic valve (31) is opened, the second electromagnetic valve (32) is closed, and liquid passes through the liquid inlet pipe(20) The tee joint (1) enters the injector (4); a push rod (42) in the injector (4) is pushed out under the action of liquid pressure, the push rod (42) drives a trigger baffle plate (64) to move, when the trigger baffle plate (64) passes through a trigger head I (61), the trigger baffle plate (64) is contacted with the trigger head I (61), a timer starts to work, and the timer times I
While recording the volume one
(ii) a Meanwhile, the push rod (42) drives the sliding block (72) to slide upwards along the linear guide rail (71) to drive the balancing weight (73) to lift in the direction opposite to the gravity, so that the balancing weight (73) provides resistance in the opposite direction to the push rod (42);
liquid continuously enters the injector (4), the push rod (42) in the injector (4) is continuously pushed out under the action of liquid pressure, the push rod (42) continuously drives the trigger blocking piece (64) to move, when the trigger blocking piece (64) passes through the second trigger head (62), the trigger blocking piece (64) is contacted with the second trigger head (62), and the second timer times
Simultaneously recording the volume two
；
The unit flow rate is:
wherein:
the flow rate is expressed in terms of a unit flow rate,
a volume representing the effective travel of the ram (42) within the syringe barrel (41),
the running time of the trigger baffle (64) between the first trigger head (61) and the second trigger head (62) is shown.
10. The flow rate measuring method according to claim 9, wherein: the volume of the active stroke of the ram (42) within the syringe barrel (41) is calibrated as follows:
setting two time timing programs which are respectively marked as a first time timing program and a second time timing program, wherein the first time timing program is used for recording the running time of the trigger barrier (64) between the first trigger head (61) and the second trigger head (62)
，
(ii) a The second time timer is used for recording the total time of multiple circulation measurement
；
To carry out
Measuring in a second continuous cycle, measuring the first time in a timing sequence
The running times of the secondary measurements, respectively
(ii) a At the total time
The liquid flowing out from the liquid outlet is introduced into the container through a pipeline, and the net weight of the container before the liquid is received is respectively measured
And total weight after receiving liquid
The volume of the effective stroke of the ram (42) within the syringe barrel (41) is then:
wherein,
a volume representing the effective travel of the ram (42) within the syringe barrel (41),
indicating temperature
The density of the liquid to be treated,
indicating the time delay correction introduced in the action communication process of the second solenoid valve (32).
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| GB1161598A (en) * | 1966-01-21 | 1969-08-13 | Sydney John Relph | Improvements relating to Quantitative Chromatography |
| GB1167408A (en) * | 1967-05-23 | 1969-10-15 | Shandon Scient Ind Ltd | Improvements in or relating to Syringes |
| GB1577833A (en) * | 1977-05-20 | 1980-10-29 | Stearns S D | Sample injection syringe |
| WO2012177259A1 (en) * | 2011-06-23 | 2012-12-27 | Aurora Sfc Systems, Llc | A low noise back pressure regulator for supercritical fluid chromatography |
| CN107064393A (en) * | 2017-05-19 | 2017-08-18 | 程宣 | It is used for the device for checking flow index of correlation in a kind of liquid chromatograph calibrating |
| CN109540010A (en) * | 2018-11-02 | 2019-03-29 | 北京卫星制造厂有限公司 | A kind of high-precision ultrahigh pressure liquid phase simulation load accumulated error test platform |
| WO2022021377A1 (en) * | 2020-07-31 | 2022-02-03 | 杭州九洋生物科技有限公司 | Pipette and pipetting method |
| CN216012342U (en) * | 2021-10-26 | 2022-03-11 | 南京派诺思科学仪器有限公司 | Constant-pressure working volume type liquid flow detection device |
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2022
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Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1161598A (en) * | 1966-01-21 | 1969-08-13 | Sydney John Relph | Improvements relating to Quantitative Chromatography |
| GB1167408A (en) * | 1967-05-23 | 1969-10-15 | Shandon Scient Ind Ltd | Improvements in or relating to Syringes |
| GB1577833A (en) * | 1977-05-20 | 1980-10-29 | Stearns S D | Sample injection syringe |
| WO2012177259A1 (en) * | 2011-06-23 | 2012-12-27 | Aurora Sfc Systems, Llc | A low noise back pressure regulator for supercritical fluid chromatography |
| CN107064393A (en) * | 2017-05-19 | 2017-08-18 | 程宣 | It is used for the device for checking flow index of correlation in a kind of liquid chromatograph calibrating |
| CN109540010A (en) * | 2018-11-02 | 2019-03-29 | 北京卫星制造厂有限公司 | A kind of high-precision ultrahigh pressure liquid phase simulation load accumulated error test platform |
| WO2022021377A1 (en) * | 2020-07-31 | 2022-02-03 | 杭州九洋生物科技有限公司 | Pipette and pipetting method |
| CN216012342U (en) * | 2021-10-26 | 2022-03-11 | 南京派诺思科学仪器有限公司 | Constant-pressure working volume type liquid flow detection device |
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| CN114487213B (en) | 2022-09-02 |
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