Online particulate matter sampling system and sampling method

Abstract

The invention discloses a particulate matter on-line sampling system and a sampling method, and relates to the field of plastic particle production sampling. The sampling system comprises a feeding pipeline which is vertically arranged, an outlet in the lower side of the feeding pipeline is communicated with a conveying pipeline, and the conveying pipeline is provided with a pneumatic conveying device; the sampling pipeline is connected to the feeding pipeline in parallel, and a first control valve is arranged on the sampling pipeline; an inlet of the sampling container is communicated with the sampling pipeline through a second control valve. According to the invention, continuous on-line sampling can be realized in the pneumatic conveying process.

Description

Technical Field

[0001] The present invention relates to the field of plastic particle production sampling, and particularly relates to an on-line continuous plastic particle sampling device and a sampling method. Background Art

[0002] After plastic products are usually extruded and granulated, small plastic particles are generated for packaging and transportation, and are supplied to downstream plastic product manufacturers for modified products. The product after the polymerization reaction is extruded and granulated to produce small plastic particles, and finally is transported to the finished product packaging through a pneumatic conveying system. Generally, the finished product particles need to be sampled and analyzed. It mainly involves detecting product appearance such as color, size, shape and other indicators, and performance indicators such as melt index, density, tensile fracture stress, and tensile fracture strain. Therefore, whether the finished product sampling is representative is crucial, which can determine whether the product meets the performance index requirements of leaving the factory and whether it can provide qualified and satisfactory products for downstream users.

[0003] Currently, the following several methods are usually adopted for sample sampling in the plastic production field: One is to set a three-way bypass valve on the vibrating screen after granulation. When sampling is required, the bypass valve is opened for sampling; the second is to set a bypass sampling line on the pipeline when the plastic particles are transported to the degassing storage bin through the pneumatic conveying system. When sampling is required, the bypass valve is opened for sampling; the third is to set a sampling bypass line on the bottom discharge line of the degassing storage bin, and the valve is opened for sampling when needed; the fourth is to sample by breaking the packaging bag on the finished product packaging line. The above sampling methods have the following technical problems: 1. The sampling is not uniform enough and the representativeness is incomplete. The above four sampling methods are all to open the valve for sampling when sampling is required. The samples taken can only represent the recent period of time and cannot completely represent a sampling cycle or a batch of products. 2. The sampling operation is highly dangerous. Because there is still a small amount of flammable gas entrained in the sample, during the sampling process, directly sampling from the production pipeline will inevitably cause the flammable gas to volatilize into the air, and it may cause fire and explosion due to static electricity generated during the sampling process. 3. The sample waste is large during the sampling process. When directly sampling from the production line, in order to ensure that the current sampling is not the dead sample of the previous time, generally, after opening the valve and flowing out the sample for a period of time, sampling is carried out again. After sampling is completed and the sampling valve is closed, there is still some sample remaining in the pipeline, which can only flow into the waste bucket and be treated as waste. Summary of the Invention

[0004] Therefore, the present invention provides a particulate matter on-line sampling system and a sampling method, which can continuously sample on-line during the pneumatic conveying process.

[0005] In view of the above technical problems, the present invention provides the following technical solutions:

[0006] An on-line particulate matter sampling system, comprising: a feeding pipeline arranged vertically, an outlet at the lower side of the feeding pipeline is communicated with a conveying pipeline, and a pneumatic conveying device is arranged on the conveying pipeline; a sampling pipeline, the sampling pipeline is connected in parallel to the feeding pipeline, and a first control valve is arranged on the sampling pipeline; a sampling container, an inlet of the sampling container is communicated with the sampling pipeline through a second control valve.

[0007] In some embodiments of the present invention, the diameter of the sampling pipeline is smaller than that of the feeding pipeline. The sampling pipeline includes a first section pipe, a second section pipe and a third section pipe which are sequentially communicated along the material flow direction. Among them, the included angle between the first section pipe and the feeding pipeline is an acute angle, the second section pipe is parallel to the feeding pipeline, and the included angle between the third section pipe and the feeding pipeline is an obtuse angle.

[0008] In some embodiments of the present invention, the sampling container is communicated with the first section pipe of the sampling pipeline through a second control valve.

[0009] In some embodiments of the present invention, the sampling container includes a sampling buffer tank and a single-sampling device. An inlet of the sampling buffer tank is communicated with a sampling outlet of the sampling pipeline through the second control valve, and an outlet of the sampling buffer tank is communicated with the single-sampling device through a seventh control valve.

[0010] In some embodiments of the present invention, the first control valve is located on the first section pipe of the sampling pipeline, and the first control valve is located on the upstream pipeline of the second control valve.

[0011] In some embodiments of the present invention, a third control valve is further arranged on the sampling pipeline, and the third control valve is located on the third section pipe.

[0012] In some embodiments of the present invention, a fourth control valve, a fifth control valve, a rotary feeder and a sixth control valve are sequentially arranged on the feeding pipeline from top to bottom. An inlet of the sampling pipeline is communicated with the pipeline between the fourth control valve and the fifth control valve, and an outlet of the sampling pipeline is communicated with the rotary feeder.

[0013] The present invention also provides an on-line particulate matter sampling method, comprising: after receiving a sampling instruction, keeping the pneumatic conveying device in an open state, controlling the first control valve to open, so that at least part of the material flows along the sampling pipeline into the conveying pipeline; after the first control valve is opened for a first set time period, controlling the second control valve to open, so that at least part of the material in the sampling pipeline enters the sampling container, and after the second control valve is opened for a second set time period, closing it to release the particulate matter in the sampling container.

[0014] In some embodiments of the present invention, the sampling container includes a sampling buffer tank and a single - time sampler. The inlet of the sampling buffer tank is communicated with the sampling outlet of the sampling pipeline through the second control valve, and the outlet of the sampling buffer tank is communicated with the single - time sampler through the third control valve. After controlling the first control valve to open for a first set duration, control the second control valve to open and the seventh control valve to close. After reaching the second set duration, close the second control valve and open the seventh control valve to release the material particles in the sampling buffer tank into the single - time sampler.

[0015] In some embodiments of the present invention, a fourth control valve, a fifth control valve, a rotary feeder, and a sixth control valve are sequentially arranged on the feeding pipeline from top to bottom. The inlet of the sampling pipeline is communicated with the pipeline between the fourth control valve and the fifth control valve, and the outlet of the sampling pipeline is communicated with the rotary feeder. After receiving the sampling instruction, control the pneumatic conveying device to open, control the fourth control valve to open and the fifth control valve to close, so that the material enters the conveying pipeline along the sampling pipeline.

[0016] The technical solution of the present invention has the following technical effects compared with the prior art:

[0017] In the particulate matter online sampling system provided by the present invention, by bypassing a sampling pipeline on the feeding pipeline and setting a sampling container communicated with the sampling pipeline, during sampling, the first control valve can be controlled to open the sampling pipeline to communicate it with the conveying pipeline, and then the second control valve is opened to make the material fall into the sampling container to achieve sampling. The whole process does not affect the continuous conveying of the conveying pipeline. Therefore, the sampling system can realize the online continuity of plastic particles, with uniform sampling and strong representativeness. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following will describe in detail the preferred embodiments of the present invention with the help of the drawings, which will help to understand the purpose and advantages of the present invention, where:

[0019] Figure 1 is a schematic structural diagram of a specific embodiment of the particulate matter online sampling system of the present invention;

[0020] Figure 2 is a partial structural diagram of a specific embodiment of the particulate matter online sampling system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will clearly and completely describe the technical solution of the present invention with reference to the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0023] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected to" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0025] As Figure 1 , Figure 2 As shown in

[0026] a specific embodiment of the particulate matter online sampling system of the present invention, which is used to realize the online continuous sampling of particulate matter. The sampling system includes a feeding pipeline 10 arranged vertically. The upper end of the feeding pipeline 10 is communicated with the outlet of the silo 20, and the lower end of the feeding pipeline 10 is communicated with the conveying pipeline 30. Among them, a pneumatic conveying device, such as a fan, etc., is provided on the conveying pipeline 30, which can convey the particulate matter passing through the feeding pipeline 10 to the next working station. The sampling system also includes a sampling pipeline 40 and a sampling container 50. Among them, the sampling pipeline 40 is connected in parallel to the feeding pipeline 10, and a first control valve 41 for controlling the opening and closing of the sampling pipeline 40 is provided on the sampling pipeline 40. The inlet of the sampling container 50 is communicated with the sampling pipeline 40 through a second control valve 42.

[0027] Specifically, in an alternative embodiment, the diameter of the sampling pipeline 40 is smaller than that of the feeding pipeline 10 to achieve continuous and small-sample sampling, meeting the representativeness of the sampled samples for a longer time. More specifically, the diameter of the sampling pipeline 40 is selected to be 25 - 50 mm; the sampling pipeline 40 includes a first section of pipe 40a, a second section of pipe 40b, and a third section of pipe 40c that are connected in sequence along the material flow direction. Among them, the included angle α between the first section of pipe 40a and the feeding pipeline 10 is an acute angle, which can reduce the resistance for particulate matter to enter the sampling pipeline 40. The second section of pipe 40b is parallel to the feeding pipeline 10, that is, arranged vertically, which can accelerate the flow rate of particulate matter. The included angle β between the third section of pipe 40c and the feeding pipeline 10 is an obtuse angle, which can make the particulate matter enter the feeding pipeline 10 more smoothly. More specifically, the included angle α between the first section of pipe 40a and the feeding pipeline 10 is 20° - 45°, and the included angle β between the third section of pipe 40c and the feeding pipeline 10 is 135° - 160°.

[0028] More specifically, a flow-limiting orifice plate 44 is provided at the inlet section of the sampling pipeline 40 to limit the sampling speed and reduce the size of the bypass air flow. The inner diameter d of the orifice plate can be determined according to the required sampling speed, and the value of d is generally 15 - 25 mm.

[0029] Specifically, in an alternative embodiment, the sampling container 50 is connected to the first section of pipe 40a of the sampling pipeline 40 through a second control valve 42. The sampling container 50 is arranged below the inclined first section of pipe 40a. Part of the particulate matter in the sampling pipeline 40 can fall into the sampling container 50 under the action of gravity, and the other part enters the conveying pipeline 30 along the sampling pipeline 40, without affecting the continuous feeding of the entire system.

[0030] Specifically, the sampling container 50 includes a sampling buffer tank 51 and a single-sampling device 52. The inlet of the sampling buffer tank 51 is communicated with the sampling outlet of the sampling pipeline 40 through the second control valve 42, and the outlet of the sampling buffer tank 51 is communicated with the single-sampling device 52 through the seventh control valve 53. Among them, the single-sampling device 52 can be selected as a sampling bucket, a sampling bottle, a sampling bag, etc. according to the situation, and its capacity is smaller than or equivalent to the capacity of the sampling buffer tank 51. During the sampling stage, the second control valve 42 is opened and the seventh control valve 53 is closed to allow particulate matter to enter the sampling buffer tank 51. When sampling is completed and sampling is to be carried out, the second control valve 42 is closed and the seventh control valve 53 is opened to achieve closed sampling of the system, isolating the system during the process of particulate matter release, so as to ensure that no combustible gas is carried out, and the sampling operation process is safer. At the same time, when the capacity of the single-sampling device 52 is smaller than the capacity of the sampling buffer tank 51, after the sample is taken, since the remaining sample in the sampling buffer tank 51 is not contaminated, it can still be returned to the system as a qualified product, reducing sampling loss.

[0031] Specifically, in an optional implementation manner, the first control valve 41 is located on the first section of the pipeline 40a of the sampling pipeline 40, and the first control valve 41 is located on the upstream pipeline of the second control valve 42. During the sampling stage, the first control valve 41 can be opened to allow the sample to enter the sampling pipeline 40 for a period of time to make the sample flow stably in the sampling pipeline 40, and then the second control valve 42 is opened to achieve sample sampling.

[0032] Specifically, in an optional implementation manner, the sampling pipeline 40 is further provided with a third control valve 43, and the third control valve 43 is located on the third section of the pipeline 40c. Among them, the first control valve 41 and the third control valve 43 are close to the feeding pipeline 10, reducing the amount of residual sample in the dead zone.

[0033] Specifically, in an optional implementation manner, a fourth control valve 11, a fifth control valve 12, a rotary feeder 13 and a sixth control valve 14 are sequentially arranged on the feeding pipeline 10 from top to bottom. The inlet of the sampling pipeline 40 is communicated with the pipeline between the fourth control valve 11 and the fifth control valve 12, and the outlet of the sampling pipeline 40 is communicated with the rotary feeder 13. The fourth control valve 11 serves as the total control valve of the entire system and is used to control the material in the feeding bin 20 to enter the feeding pipeline 10 and / or the sampling pipeline 40. The fifth control valve 12 is used to control the opening or closing of the feeding pipeline 10. The rotary feeder 13 operates to buffer the particles and send them from the downstream of the feeding pipeline 10 to the conveying pipeline. The sixth control valve 14 is used to control the opening or closing of the feeding pipeline 10 between the rotary feeder 13 and the conveying pipeline 30.

[0034] Specifically, among the above seven control valves of the present invention, that is, the first control valve 41 to the seventh control valve 43 are all flap valves.

[0035] The present invention also provides a sampling method for the above particulate matter online sampling system. The sampling method can adopt manual sampling or automatic sampling, and it includes the following processes:

[0036] After receiving the sampling instruction, keep the pneumatic conveying device in the open state; specifically, before sampling, the feeding pipeline 10 is kept open. Under the action of the pneumatic conveying device, the particulate matter moves along the feeding pipeline 10 and the conveying pipeline 30 to the next working station. When sampling, keep the pneumatic conveying device in the open state to keep the system in a continuous working state; specifically, in an optional implementation manner, control the fourth control valve 11 to open and the fifth control valve 12 to close, so that the material enters the conveying pipeline 30 along the sampling pipeline 40. In another alternative implementation manner, control the fourth control valve 11 to open and the fifth control valve 12 to open, so that the material enters the conveying pipeline 30 together along the feeding pipeline 10 and the sampling pipeline 40;

[0037] Control the first control valve 41 to open, so that at least part of the material flows along the sampling pipeline 40 into the conveying pipeline 30; after the first control valve 41 is opened for a first set time period, control the second control valve 42 to open. For example, open the first control valve 41 to make the system circulate along the sampling pipeline 40 for 2 - 5 minutes; when the second control valve 42 is opened, at least part of the material in the sampling pipeline 40 enters the sampling container 50;

[0038] After the second control valve 42 is opened for a second set time period, it is closed to release the material particles in the sampling container 50; specifically, in one implementation manner, when the sampling container 50 includes a sampling buffer tank 51 and a single - time sampler 52, when opening the second control valve 42 to make at least part of the material in the sampling pipeline 40 enter the sampling container 50, keep the seventh control valve 53 in the closed state. When the second control valve 42 is opened for the second set time period and then closed, open the seventh control valve 53 to release the material particles in the sampling buffer tank 51 into the single - time sampler 52 for sampling. When the capacity of the single - time sampler 52 is less than the capacity of the sampling buffer tank 51, after sampling, close the seventh control valve 53 and open the second control valve 42. The material in the sampling buffer tank 51 can also return to the circulation pipeline under the action of the power device of the system and continue to flow into the conveying pipeline 30 to save materials.

[0039] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or modifications derived therefrom still fall within the protection scope of the present invention.

Claims

1. A particle online sampling system, characterized in that: include: A feed pipeline arranged vertically, the outlet at the lower side of the feed pipeline is connected to the conveying pipeline, and the conveying pipeline is provided with a pneumatic conveying device; A sampling pipeline, the sampling pipeline is connected in parallel to the feed pipeline, and a first control valve is provided on the sampling pipeline; A sampling container, the inlet of which is connected to the sampling pipeline through a second control valve.

2. The particle online sampling system according to claim 1, characterized in that: The diameter of the sampling pipeline is smaller than the diameter of the supply pipeline. The sampling pipeline includes a first section of pipe, a second section of pipe and a third section of pipe which are connected in sequence along the material flow direction, wherein the angle between the first section of pipe and the supply pipeline is an acute angle, the second section of pipe is parallel to the supply pipeline, and the angle between the third section of pipe and the supply pipeline is an obtuse angle.

3. The particle online sampling system according to claim 2, characterized in that: The sampling container is communicated with the first section of the sampling pipeline through a second control valve.

4. The particle online sampling system according to claim 1, characterized in that: The sampling container includes a sampling buffer tank and a single sampler. The inlet of the sampling buffer tank is connected to the sampling outlet of the sampling pipeline through the second control valve, and the outlet of the sampling buffer tank is connected to the single sampler through the seventh control valve.

5. The particle online sampling system according to claim 2, characterized in that: The first control valve is located on a first section of the sampling pipeline, and the first control valve is located in an upstream pipeline of the second control valve.

6. The particle online sampling system according to claim 2, characterized in that: The sampling pipeline is also provided with a third control valve, and the third control valve is located on the third section of the pipe.

7. The particle online sampling system according to claim 1, characterized in that: The fourth control valve, the fifth control valve, the rotary feeder and the sixth control valve are sequentially arranged on the feed pipeline from top to bottom, the inlet of the sampling pipeline is connected to the pipeline between the fourth control valve and the fifth control valve, and the outlet of the sampling pipeline is connected to the rotary feeder.

8. A method for online sampling of particulate matter, characterized in that: include: After receiving the sampling instruction, the pneumatic conveying device is kept in the open state, and the first control valve is controlled to open, so that at least part of the material flows along the sampling pipeline into the conveying pipeline; after the first control valve is opened for a first set time, the second control valve is controlled to open, so that at least part of the material in the sampling pipeline enters the sampling container; after the second control valve is opened for a second set time, it is closed to release the material particles in the sampling container.

9. The method for online sampling of particulate matter according to claim 8, characterized in that: The sampling container includes a sampling buffer tank and a single sampler, the inlet of the sampling buffer tank is connected to the sampling outlet of the sampling pipeline through the second control valve, and the outlet of the sampling buffer tank is connected to the single sampler through the third control valve; After controlling the first control valve to open for the first set time, control the second control valve to open and the seventh control valve to close. After reaching the second set time, close the second control valve and open the seventh control valve to release the material particles in the sampling buffer tank into the single sampler.

10. The method for online sampling of particulate matter according to claim 8, characterized in that: The feed pipeline is provided with a fourth control valve, a fifth control valve, a rotary feeder and a sixth control valve in sequence from top to bottom, the inlet of the sampling pipeline is connected to the pipeline between the fourth control valve and the fifth control valve, and the outlet of the sampling pipeline is connected to the rotary feeder; After receiving the sampling instruction, the pneumatic conveying device is controlled to open, the fourth control valve is controlled to open, and the fifth control valve is controlled to close, so that the material enters the conveying pipeline along the sampling pipeline.

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