Liquid vacuum sampling system and method

Abstract

The invention relates to the technical field of vacuum sampling, in particular to a liquid vacuum sampling system and method.The liquid vacuum sampling system comprises a vacuum control mechanism, a nitrogen balance mechanism and a sampling mechanism; the sampling mechanism comprises a liquid collecting hopper, the bottom end of the liquid collecting hopper is connected with an under-liquid sampling pipe, and the bottom end of the under-liquid sampling pipe is inserted below the stirring liquid level of the container; and the vacuum control mechanism and the nitrogen balance mechanism are both connected with the liquid collecting hopper. According to the liquid vacuum sampling system and method, a vacuum environment can be provided for the interior of the liquid collecting hopper by arranging the vacuum control mechanism, and nitrogen can be introduced into the container during sampling by arranging the nitrogen balancing mechanism to balance the pressure in the container, so that continuous liquid stirring sampling and sampling without opening a manhole can be realized in the operation process of the closed container; the sampling process is simpler and more convenient, and meanwhile, the safety and the environmental protection property during sampling can be improved under the complex working conditions that materials are flammable and explosive and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of vacuum sampling, and in particular to a liquid vacuum sampling system and method. Background Art

[0002] Currently, sampling liquids from stirred tanks or reactors relies on manual lifting or releasing liquids from bottom valves. Common sampling locations include manholes, sampling valves, and bottom valves. This presents a series of challenges, including difficulty and high risk when the stirred tank is under vacuum or positive pressure, when continuous reaction requires continuous stirring, or when the materials are flammable or explosive. Furthermore, the storage and handling of post-sampling tooling can pose a series of safety and environmental concerns. Therefore, we propose a liquid vacuum sampling system and method. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a liquid vacuum sampling system and method, which solves the problems of sampling difficulty, high sampling risk, and safety and environmental protection after sampling in current sampling systems and methods when facing vacuum and positive pressure conditions, continuous reaction and non-stop stirring conditions, and flammable and explosive material conditions.

[0004] To achieve the above-mentioned object, a first aspect of an embodiment of the present invention provides a liquid vacuum sampling system, comprising a vacuum control mechanism, a nitrogen balancing mechanism, and a sampling mechanism; The sampling mechanism includes a liquid collecting hopper, the bottom end of which is connected to a submerged sampling tube, the bottom end of which is inserted below the stirring level of the container; The vacuum control mechanism and the nitrogen balance mechanism are both connected to the liquid collecting hopper.

[0005] As a preferred technical solution, a sampling valve is installed on the submerged sampling tube, and a quick-opening sampling port is provided on the top of the liquid collecting hopper.

[0006] As a preferred technical solution, a pressure transmitter is provided at the top of the liquid collecting hopper, and a differential pressure level gauge is provided at the bottom of the liquid collecting hopper.

[0007] As an optimal technical solution, the vacuum control mechanism includes a vacuum distribution pipe, one end of which is connected to vacuum connecting pipe 1 and vacuum connecting pipe 2 through a tee, the bottom end of vacuum connecting pipe 1 is inserted into the container, a stirring vacuum valve is installed on vacuum connecting pipe 1, one end of vacuum connecting pipe 2 is connected to the liquid collecting bucket, and a sampling vacuum valve is installed on vacuum connecting pipe 2.

[0008] As a preferred technical solution, the vacuum control mechanism further includes a vacuum pipe, one end of the vacuum pipe is connected to a protection buffer tank, and one end of the vacuum distribution pipe is inserted into the protection buffer tank.

[0009] As a preferred technical solution, the bottom end of the protection buffer tank is connected to a reflux pipe, the bottom end of the reflux pipe is inserted into the container, and a reflux valve is installed on the reflux pipe.

[0010] As a preferred technical solution, the nitrogen balancing mechanism includes a nitrogen main pipe, one end of which is connected to a nitrogen inlet pipe and a rupture pipe through a tee, the bottom end of the nitrogen inlet pipe is inserted into the container, a balancing nitrogen valve is installed on the nitrogen inlet pipe, one end of the rupture pipe is connected to a liquid collecting hopper, and a rupture nitrogen valve is installed on the rupture pipe.

[0011] A second aspect of an embodiment of the present invention provides a liquid vacuum sampling method, comprising the following steps: S1, preparation, stirring vacuum valve and reflux valve are closed, sampling valve is opened; S2, cleaning, the sampling vacuum valve and the balancing nitrogen valve are opened, the liquid enters the liquid collecting hopper through the submersible sampling tube, when the liquid level in the collecting hopper reaches the upper limit, the sampling vacuum valve is closed, the balancing nitrogen valve is closed, and the liquid in the collecting hopper flows back to the container through the submersible sampling tube under the action of gravity; S3, pumping liquid, the sampling vacuum valve and the balancing nitrogen valve are opened, and the liquid enters the liquid collecting hopper through the submersible sampling tube. When the liquid level in the collecting hopper reaches the upper limit, the sampling valve, the sampling vacuum valve and the balancing nitrogen valve are closed, and the liquid stays in the collecting hopper; S4, sampling, the nitrogen valve is opened, the pressure in the liquid collecting hopper increases, when the pressure in the liquid collecting hopper reaches the upper limit, the nitrogen valve is closed, and then the sampling port is manually opened for sampling. After sampling is completed, the sampling port is closed; S5, draining, the reflux valve, sampling valve and stirring vacuum valve are opened. At this time, the liquid in the collecting bucket flows back to the container through the submersible sampling tube. When the liquid level in the collecting bucket drops to the lower limit, the sampling valve is closed and the draining is completed.

[0012] As a preferred technical solution, the number of cleaning times in step S2 is determined according to the viscosity of the material in the container. The greater the viscosity of the material, the more times the cleaning cycle is performed. When the viscosity of the material is between 0cp and 5000cp, the number of cycles is 3 to 5 times.

[0013] As a preferred technical solution, the upper limit of the liquid level in the collecting hopper is 75%-90% of the height of the collecting hopper, the upper limit of the liquid level in the collecting hopper is 0%-5% of the height of the collecting hopper, and the upper limit of the pressure in the collecting hopper is -500pa-500pa.

[0014] By means of the above technical solution, the present invention provides a liquid vacuum sampling system and method. These have at least the following beneficial effects: The liquid vacuum sampling system and method, by providing a vacuum control mechanism, can provide a vacuum environment within the liquid collecting hopper. By providing a nitrogen balancing mechanism, nitrogen can be introduced into the container during sampling to balance the pressure within the container. This allows for continuous stirring of the liquid during operation in a closed container and for sampling without opening a manhole, making the sampling process simpler and more convenient. Furthermore, the system and method can improve the safety and environmental friendliness of sampling in complex working conditions, such as when working with flammable and explosive materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application: Figure 1 This is a schematic diagram of the overall structure of the first embodiment of the present invention; Figure 2 Schematic diagram of the structure of the vacuum control mechanism, nitrogen balance mechanism and sampling mechanism in Example 1 of the present invention; Figure 3 This is a schematic diagram of the method control flow of embodiment 2 of the present invention.

[0016] In the figure: 1. Vacuum control mechanism; 101. Vacuum pipe; 102. Protection buffer tank; 103. Reflux valve; 104. Reflux pipe; 105. Vacuum distribution pipe; 106. Stirring vacuum valve; 107. Sampling vacuum valve; 108. Vacuum connecting pipe 1; 109. Vacuum connecting pipe 2; 2. Nitrogen balancing mechanism; 201. Nitrogen main pipe; 202. Nitrogen inlet pipe; 203. Balancing nitrogen valve; 204. Nitrogen rupture valve; 205. Explosion pipe; 3. Sampling mechanism; 301. Liquid collecting hopper; 302. Submerged sampling pipe; 303. Sampling valve; 304. Sampling port; 305. Pressure transmitter; 306. Differential pressure level gauge. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] Example 1 See also Figure 1-Figure 2 , a technical solution provided by this embodiment: A liquid vacuum sampling system is suitable for closed containers such as stirring kettles and reactors, and is particularly suitable for normal pressure or negative pressure conditions in the container, wherein the container is a device used to hold liquid and provide stirring power.

[0019] The liquid vacuum sampling system consists of two parts: a sampling device and a PLC control system.

[0020] Among them, the sampling device includes a vacuum control mechanism 1, a nitrogen balance mechanism 2 and a sampling mechanism 3. The vacuum control mechanism 1 is used to control the vacuum state in the stirring container and the sampling mechanism 3. The nitrogen balance mechanism 2 is used to introduce an appropriate amount of nitrogen into the stirring container during the sampling process to balance the internal air pressure of the stirring container. The sampling mechanism 3 is used for sampling. A closed environment can be achieved inside the sampling mechanism 3 to improve the safety and environmental protection during the sampling process, so that the system can be applied to special working conditions such as flammable, explosive and volatile materials.

[0021] Specifically, the sampling mechanism 3 in this embodiment includes a liquid collecting hopper 301, which has a liquid collecting chamber within it for temporarily storing liquid during the sampling process. The hopper 301 is conical, with a larger top and smaller bottom, facilitating liquid collection. A submerged sampling tube 302 is connected to the bottom of the hopper 301. The bottom end of the submerged sampling tube 302 is inserted into the container, and the bottom outlet of the submerged sampling tube 302 remains below the container's stirring level, facilitating the suction of the sampled liquid into the hopper 301 through vacuum pressure.

[0022] Furthermore, a sampling valve 303 is installed on the submerged sampling tube 302. The sampling valve 303 is used to control the connection and disconnection between the container and the liquid collecting hopper 301. The top of the liquid collecting hopper 301 is provided with a sampling port 304. The sampling port 304 is a quick-opening design. When the sampling port 304 is closed, the liquid collecting chamber can remain sealed. When it is opened, sampling can be taken from the liquid collecting chamber.

[0023] Furthermore, a pressure transmitter 305 is provided at the top of the liquid collecting hopper 301, and the pressure transmitter 305 is used to monitor the pressure changes inside the liquid collecting chamber in real time. A differential pressure level gauge 306 is provided at the bottom of the liquid collecting hopper 301, and the differential pressure level gauge 306 is used to monitor the liquid level changes in the liquid collecting hopper 301 in real time.

[0024] The vacuum control mechanism 1 in this embodiment includes a vacuum pipe 101, which is used to provide vacuum for the container and the sampling system. One end of the vacuum pipe 101 is connected to an external vacuum device, and the other end of the vacuum pipe 101 is connected to a protective buffer tank 102, which is used to protect the vacuum system.

[0025] A vacuum distribution pipe 105 is plugged into the top of the protective buffer tank 102. The end of the vacuum distribution pipe 105 away from the protective buffer tank 102 is connected to vacuum connecting pipe 1 108 and vacuum connecting pipe 2 109 through a tee. The bottom end of vacuum connecting pipe 108 is plugged into the container to provide a vacuum environment inside the container. A stirring vacuum valve 106 is installed on vacuum connecting pipe 108 to control the connection and disconnection between the container and the vacuum pipe 101. One end of vacuum connecting pipe 2 109 is connected to the liquid collecting hopper 101 to provide the vacuum environment required for sampling. A sampling vacuum valve 107 is installed on vacuum connecting pipe 2 109 to control the connection and disconnection between the sampling mechanism 3 and the vacuum pipe 101. Furthermore, the bottom end of the protection buffer tank 102 is connected to a reflux pipe 104, the bottom end of the reflux pipe 104 is inserted into the container 5, and is used to relieve the pressure of the liquid collecting bucket 301 after sampling. A reflux valve 103 is installed on the reflux pipe 104, and the reflux valve 103 is used to control the connection and disconnection of the reflux pipe 104.

[0026] In this embodiment, the nitrogen balancing mechanism 2 includes a nitrogen main pipe 201, which is used to provide nitrogen. One end of the nitrogen main pipe 201 is connected to an external nitrogen supply device, and the other end is connected to a nitrogen inlet pipe 202 and a rupture pipe 205 through a tee. The bottom end of the nitrogen inlet pipe 202 is inserted into the container and is used to input nitrogen into the container to balance the pressure in the container. A balancing nitrogen valve 203 is installed on the nitrogen inlet pipe 202, and the balancing nitrogen valve 203 is used to control the connection and disconnection between the container and the nitrogen main pipe 201. One end of the rupture pipe 205 is connected to the liquid collecting hopper 101, and a rupture nitrogen valve 204 is installed on the rupture pipe 205, and the rupture nitrogen valve 204 is used to control the connection and disconnection between the liquid collecting hopper 101 and the nitrogen main pipe 201.

[0027] In addition, the PLC control system includes a parameter setting and operation interface, CPU, memory, power module, communication module, etc., which are used to receive the input of feedback signals from the sampling device and output control signals to the sampling device to control the operation of the sampling device.

[0028] Example 2 See also Figure 3 , this embodiment provides a semi-automatic liquid vacuum sampling method, comprising the following steps: S1. Preparation: First, set the PLC control system parameters according to the material characteristics; Set the number of cleaning and replacement cycles according to the material characteristics. The higher the viscosity, the more cycles. For low-viscosity liquids 0cp-5000cp, set the number of cycles to 3-5 times. For high-viscosity materials, increase the number of cycles as appropriate. Set the upper and lower limits of the liquid level in the liquid collecting chamber, with the upper limit being 75%-90% and the lower limit being 0%-5%; Set the upper limit of the liquid collecting chamber pressure to -500Pa-500Pa; The stirring vacuum valve 106 and the reflux valve 103 are closed, so that the connection between the container and the vacuum pipe 101 is disconnected, the sampling valve 303 is opened, and the sampling vacuum valve 107 is opened, so that the liquid collecting chamber is in a vacuum state; S2, cleaning, the sampling vacuum valve 107 is opened, the balancing nitrogen valve 203 is opened, and nitrogen enters the container at this time. At the same time, the liquid enters the liquid collecting hopper 301 through the submerged sampling tube 302, and the liquid level in the liquid collecting hopper 301 rises. When the liquid level reaches the upper limit set by the differential pressure level gauge 306, the sampling vacuum valve 107 is closed, and the balancing nitrogen valve 203 is closed. The liquid in the liquid collecting hopper 301 flows back to the container through the submerged sampling tube 302 under the action of gravity. At this point, the cleaning cycle count +1, and the cleaning and replacement action is repeated continuously. When the number of cycles is reached, it enters the next stage; S3, draw liquid, the sampling vacuum valve 107 is opened, the balancing nitrogen valve 203 is opened, and nitrogen enters the container. At this time, the liquid enters the liquid collecting hopper 301 through the submerged sampling tube 302. The liquid level in the liquid collecting hopper 301 rises. When the liquid level reaches the upper limit set by the differential pressure level gauge 306, the sampling valve 303 is closed, the sampling vacuum valve 107 is closed, and the balancing nitrogen valve 203 is closed. At this time, the liquid stays in the liquid collecting hopper 301. S4, sampling, the nitrogen valve 204 is opened, the pressure in the liquid collecting chamber begins to rise, and when the pressure value monitored by the pressure transmitter 305 reaches the upper limit of the parameter setting, the nitrogen valve 204 is closed. At this time, the system gives a sampling signal, and the operation is switched to manual. The sampling port 304 is manually opened for sampling. After sampling is completed, the sampling port 304 is closed; S5, draining. After closing the sampling port 304, a draining signal is given, the reflux valve 103 is opened, the sampling valve 303 is opened, and the stirring vacuum valve 106 is opened. At this time, the liquid in the collecting hopper 301 flows back to the container through the submerged sampling tube 302. When the differential pressure level gauge 306 detects that the liquid level in the collecting hopper 301 reaches the lower limit of the liquid level setting, the sampling valve 303 is closed, and the draining is completed. It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0029] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A liquid vacuum sampling system, characterized in that: It includes a vacuum control mechanism (1), a nitrogen balance mechanism (2) and a sampling mechanism (3); The sampling mechanism (3) comprises a liquid collecting hopper (301), the bottom end of the liquid collecting hopper (301) is connected to a submerged sampling tube (302), and the bottom end of the submerged sampling tube (302) is inserted below the stirring liquid level of the container; The vacuum control mechanism (1) and the nitrogen balance mechanism (2) are both connected to the liquid collecting hopper (301).

2. The liquid vacuum sampling system according to claim 1, characterized in that: A sampling valve (303) is installed on the submerged sampling tube (302), and a quick-opening sampling port (304) is provided on the top of the liquid collecting hopper (301).

3. The liquid vacuum sampling system according to claim 1, characterized in that: A pressure transmitter (305) is provided at the top end of the liquid collecting hopper (301), and a differential pressure level gauge (306) is provided at the bottom end of the liquid collecting hopper (301).

4. The liquid vacuum sampling system according to claim 1, characterized in that: The vacuum control mechanism (1) includes a vacuum distribution pipe (105), one end of the vacuum distribution pipe (105) is connected to a vacuum connecting pipe 1 (108) and a vacuum connecting pipe 2 (109) through a three-way connection, the bottom end of the vacuum connecting pipe 1 (108) is inserted into the container, and a stirring vacuum valve (106) is installed on the vacuum connecting pipe 1 (108), one end of the vacuum connecting pipe 2 (109) is connected to the liquid collecting hopper (301), and a sampling vacuum valve (107) is installed on the vacuum connecting pipe 2 (109).

5. The liquid vacuum sampling system according to claim 1, characterized in that: The vacuum control mechanism (1) further comprises a vacuum pipe (101), one end of the vacuum pipe (101) is connected to a protection buffer tank (102), and one end of the vacuum distribution pipe (105) is plugged into the protection buffer tank (102).

6. The liquid vacuum sampling system according to claim 5, characterized in that: The bottom end of the protection buffer tank (102) is connected to a reflux pipe (104), the bottom end of the reflux pipe (104) is plugged into the container, and a reflux valve (103) is installed on the reflux pipe (104).

7. The liquid vacuum sampling system according to claim 1, characterized in that: The nitrogen balancing mechanism (2) comprises a nitrogen main pipe (201), one end of the nitrogen main pipe (201) is connected to a nitrogen inlet pipe (202) and a rupture pipe (205) via a tee, the bottom end of the nitrogen inlet pipe (202) is inserted into the container, a balancing nitrogen valve (203) is installed on the nitrogen inlet pipe (202), one end of the rupture pipe (205) is connected to a liquid collecting hopper (301), and a rupture nitrogen valve (204) is installed on the rupture pipe (205).

8. A liquid vacuum sampling method, characterized in that: The following steps are involved: S1, preparation, stirring vacuum valve (106) and reflux valve (103) are closed, and sampling valve (303) is opened; S2, cleaning, the sampling vacuum valve (107) and the balancing nitrogen valve (203) are opened, and the liquid enters the liquid collecting hopper (301) through the submerged sampling tube (302). When the liquid level in the liquid collecting hopper (301) reaches the upper limit, the sampling vacuum valve (107) is closed, the balancing nitrogen valve (203) is closed, and the liquid in the liquid collecting hopper (301) flows back to the container through the submerged sampling tube (302) under the action of gravity; S3, liquid is drawn, the sampling vacuum valve (107) and the balancing nitrogen valve (203) are opened, and the liquid enters the liquid collecting bucket (301) through the submerged sampling tube (302). When the liquid level in the liquid collecting bucket (301) reaches the upper limit, the sampling valve (303), the sampling vacuum valve (107) and the balancing nitrogen valve (203) are closed, and the liquid remains in the liquid collecting bucket (301); S4, sampling, the nitrogen valve (204) is opened, the pressure in the liquid collecting hopper (301) rises, when the pressure in the liquid collecting hopper (301) reaches the upper limit, the nitrogen valve (204) is closed, and then the sampling port (304) is manually opened to take samples, and after the sampling is completed, the sampling port (304) is closed; S5, draining, the reflux valve (103), the sampling valve (303) and the stirring vacuum valve (106) are opened. At this time, the liquid in the collecting hopper (301) flows back to the container through the submerged sampling tube (302). When the liquid level in the collecting hopper (301) drops to the lower limit, the sampling valve (303) is closed and the draining is completed.

9. The liquid vacuum sampling method according to claim 8, characterized in that: The number of cleaning times in step S2 is determined according to the viscosity of the material in the container. The greater the viscosity of the material, the more times the cleaning cycles are performed. When the viscosity of the material is between 0 cp and 5000 cp, the number of cycles is 3 to 5 times.

10. The liquid vacuum sampling method according to claim 8, characterized in that: The upper limit of the liquid level in the liquid collecting hopper (301) is 75%-90% of the height of the liquid collecting hopper (301), the upper limit of the liquid level in the liquid collecting hopper (301) is 0%-5% of the height of the liquid collecting hopper (301), and the upper limit of the pressure in the liquid collecting hopper (301) is -500 Pa-500 Pa.

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