Environment-friendly liquid formaldehyde negative pressure sampling system

Abstract

The utility model relates to the technical field of formaldehyde production, in particular to an environment-friendly liquid formaldehyde negative pressure sampling system. Under the action of the sampling pump, liquid formaldehyde flows to the sampling bin through the main pipeline, the sampling barrel can achieve sampling operation within a certain time period, and in another time period, a liquid formaldehyde stub bar or liquid formaldehyde remaining amount is collected at the bottom of the sampling bin. Under the action of the negative pressure generation unit, the liquid storage cavity of the waste liquid storage tank and the sampling cavity of the sampling bin are always kept in a negative pressure state. Thus, in the sampling process, the interiors of the sampling pump and the sampling pipeline are always kept in a negative pressure state, after sampling is completed, the sampling pump and the sampling pipeline can be isolated from the external environment, and the accuracy of subsequent quality inspection results is guaranteed; furthermore, under the action of negative pressure, the liquid formaldehyde stub bar or the residual liquid formaldehyde can be collected properly; in addition, in the process of purging and cleaning by means of low-pressure steam, the formaldehyde gas phase is properly sucked into the waste liquid storage tank under the action of negative pressure.

Description

Technical Field

[0001] The utility model relates to the technical field of formaldehyde production, in particular to an environmentally friendly liquid formaldehyde negative pressure sampling system. Background Art

[0002] During the formaldehyde production process, it is necessary to regularly sample and inspect it to ensure that its preparation quality meets the acceptance standards. Figure 1 As shown in , conventional sampling is usually performed using a sampling pump, that is, the negative pressure generated by the sampling pump is used to extract formaldehyde in the main pipeline, and then it is directly pumped into the sampling bucket through the sampling pipeline for storage and inspection. However, in the actual sampling process, there are the following problems: 1) It is very easy for debris, dust and other impurities to remain inside the sampling pump and the sampling pipeline. If sampling is performed as usual, it will affect the purity of the sampled formaldehyde, which will inevitably affect the accuracy of the quality inspection results; if the material head is removed (that is, the sampling pipeline discharges formaldehyde for a period of time before it is collected by the sampling bucket), it will take a lot of manpower and material resources to properly preserve it. If the operation is improper, it is very easy to pollute the workshop floor and air quality problems; 2) In the sampling process, the sampling pump and the sampling pipeline are It is inevitable that formaldehyde will remain inside the pipeline, which will easily lead to blockage over time. As far as the current industry situation is concerned, using low-pressure steam to blow the sampling pump and the inside of the sampling tube after sampling can effectively remove formaldehyde, but at the same time, a large amount of formaldehyde gas will volatilize, which will affect the workshop and the surrounding atmospheric environment. 3) During the sampling process, if you are not careful, formaldehyde can easily "leak" through the outlet of the sampling pipeline, thereby contaminating the sampling table or the workshop floor, and a lot of effort will be required for cleaning later.

[0003] In order to deal with the above problems, the company purchased a closed formaldehyde sampling system. However, the purchase price is extremely high, the piping is complex, the operation is cumbersome, and the corresponding sampling bottles are required. It cannot handle the material heads and tails generated during the sampling process, and the sampling pipeline cannot be flushed, which is still very easy to cause pipeline blockage and cannot meet expectations. Therefore, technical personnel are urgently needed to solve the above problems. Summary of the invention

[0004] Therefore, in view of the above-mentioned existing problems and defects, the designers of the present invention collected relevant information, conducted multiple evaluations and considerations, and continued to experiment and modify the system after many years of R&D experience by technicians engaged in this industry, which ultimately led to the emergence of the environmentally friendly liquid formaldehyde negative pressure sampling system.

[0005] In order to solve the above technical problems, the utility model relates to an environmentally friendly liquid formaldehyde negative pressure sampling system, including a sampling pump, a first stop valve, a sampling chamber, a sampling barrel, a second stop valve, a waste liquid storage tank and a negative pressure generating unit. Under the pumping force of the sampling pump, the liquid formaldehyde flows to the sampling chamber in sequence through the main pipeline and the first stop valve. In a certain time period, the sampling barrel placed in the sampling chamber of the sampling chamber can realize the liquid formaldehyde sampling operation, and in another time period, the liquid formaldehyde head or the liquid formaldehyde residue is collected at the bottom of the sampling chamber. The waste liquid storage tank is connected to the sampling chamber. The negative pressure generating unit is matched with the waste liquid storage tank so that its liquid storage chamber is always kept in a negative pressure state. Concomitantly, the sampling chamber of the sampling chamber is also maintained in a negative pressure state. The liquid formaldehyde head or the liquid formaldehyde residue collected at the bottom of the sampling chamber can be circulated to the waste liquid storage tank through the second stop valve under the action of negative pressure to complete the collection.

[0006] As a further improvement of the technical solution disclosed in the utility model, the negative pressure generating unit is preferably a vacuum generator, and the top wall or side wall of the waste liquid storage tank is used as an installation reference.

[0007] Of course, as another type of design of the above technical solution, the negative pressure generating unit includes a centrifugal pump and a jet pump. The jet pump and the centrifugal pump are respectively arranged at the upstream and downstream of the waste liquid storage tank, and are assisted by pipelines to form a liquid formaldehyde circulation loop, and the sampling chamber is connected to the jet pump. During the sampling process, the centrifugal pump is maintained in the on state, and the formaldehyde waste liquid temporarily stored in the waste liquid storage tank flows through the centrifugal pump and the jet pump in sequence and flows back to the waste liquid storage tank. At the same time, the jet pump forms a negative pressure in its working chamber based on the Bernoulli principle, and the liquid formaldehyde head or excess liquid formaldehyde collected at the bottom of the sampling chamber can be drained to the waste liquid storage tank under the action of negative pressure.

[0008] As a further improvement of the technical solution disclosed in the utility model, a filter cover is provided inside the waste liquid storage tank. The filter cover is used to filter impurities from the liquid formaldehyde feed or excess liquid formaldehyde pre-circulated to the centrifugal pump, and is detachably fixed to the inner wall of the waste liquid storage tank.

[0009] As a further improvement of the technical solution disclosed in the utility model, the sampling bin includes a bin shell, a sampling conduit and a mesh plate. The bin shell is in the shape of a variable-caliber funnel, and a material taking port is provided on its side wall for the sampling barrel to freely pass through. The sampling conduit is used to guide the liquid formaldehyde flowing through the main pipeline to the sampling bin, and it is inserted on the top wall of the bin shell. The mesh plate is used to place the sampling barrel, which is placed horizontally in the cavity of the bin shell and is located directly below the sampling conduit.

[0010] As a further improvement of the technical solution disclosed in the utility model, the sampling chamber also includes a side door, an upper hinge and a lower hinge. The side door is assembled with the side wall of the sampling chamber by means of the upper hinge and the lower hinge, and can freely perform rotational movement when subjected to push and pull forces, so that the material taking port can be blocked or opened.

[0011] As a further improvement of the technical solution disclosed in the utility model, the sampling chamber also includes a limiting ring. The limiting ring is used to ensure that the placed sampling bucket and the sampling conduit remain aligned, and the limiting ring is placed on and fixed to the top wall of the mesh plate.

[0012] In practical applications, the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model has achieved at least the following beneficial technical effects, specifically:

[0013] 1) During the sampling process, the inside of the sampling pump and the sampling pipeline is always maintained in a negative pressure state, and after the sampling is completed, it is conducive to isolating the sampling pump and the sampling pipeline from the external environment, effectively preventing the intrusion of external debris, dust and other impurities. The inside of the sampling pump and the sampling pipeline is always kept in a clean state, which is conducive to ensuring the purity of the sampled formaldehyde, and ultimately ensuring the accuracy of the subsequent quality inspection results;

[0014] 2) Under the action of negative pressure, the liquid formaldehyde head collected at the bottom of the sampling chamber or the residual liquid formaldehyde caused by "leakage" is collected in a timely and proper manner into the waste liquid storage tank, thereby effectively avoiding the occurrence of formaldehyde pollution of the workshop floor or gaseous formaldehyde causing adverse effects on the atmospheric environment; in addition, due to the negative pressure, after the sampling is completed, a large amount of formaldehyde will not remain inside the sampling pump and the sampling pipeline, which means that the pipeline is unlikely to be blocked;

[0015] 3) In extreme cases, even if low-pressure steam is needed to purge the sampling pump and the inside of the sampling tube after sampling, the formaldehyde gas phase will still be sucked into the waste liquid storage tank under the action of negative pressure, and will not evaporate into the surrounding atmospheric environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of a liquid formaldehyde sampling system in the prior art.

[0018] Figure 2It is a structural schematic diagram of the first embodiment of the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model.

[0019] Figure 3 It is a structural schematic diagram of a sampling bin in a first embodiment of the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model.

[0020] Figure 4 It is a structural schematic diagram of a second embodiment of the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model.

[0021] 1-sampling pump; 2-first stop valve; 3-sampling chamber; 31-chamber shell; 311-feeding port; 32-sampling catheter; 33-mesh plate; 34-side door; 35-upper loose-leaf; 36-lower loose-leaf; 37-limiting ring; 4-sampling bucket; 5-second stop valve; 6-waste liquid storage tank; 61-filter cover; 7-negative pressure generating unit; 71-centrifugal pump; 72-jet pump; 73-vacuum generator. DETAILED DESCRIPTION

[0022] In the description of the present invention, it should be understood that the terms "front", "rear", "up", "down", "left", "right", etc., indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are 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 direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0023] The following is a further detailed description of the contents disclosed in the present utility model in conjunction with specific embodiments. Figure 2 The schematic diagram of the structure of the first embodiment of the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model is shown. It can be seen that it is mainly composed of a sampling pump 1, a first stop valve 2, a sampling chamber 3, a sampling barrel 4, a second stop valve 5, a waste liquid storage tank 6 and a negative pressure generating unit 7. Under the pumping force of the sampling pump 1, the liquid formaldehyde to be sampled flows to the sampling chamber 3 through the main pipeline and the first stop valve 2 in sequence. During the sampling time period, the sampling barrel 4 placed in the sampling cavity of the sampling chamber 3 can realize the liquid formaldehyde sampling operation, and during the non-sampling time period, the liquid formaldehyde head or the liquid formaldehyde residue is collected at the bottom of the sampling chamber 3. The waste liquid storage tank 6 is connected to the sampling chamber 3. The negative pressure generating unit 7 is matched with the waste liquid storage tank 6 so that its liquid storage chamber is always maintained in a negative pressure state. Concomitantly, the sampling chamber of the sampling chamber 3 is also maintained in a negative pressure state. The liquid formaldehyde head or liquid formaldehyde residue collected at the bottom of the sampling chamber 3 can flow to the waste liquid storage tank 6 through the second stop valve 5 under the action of negative pressure to complete the collection.

[0024] The liquid formaldehyde head mentioned above is produced during the initial stage of sampling, while the residual liquid formaldehyde is caused by the leakage of formaldehyde remaining in the sampling pipeline (i.e., the sampling conduit 32 in the following text) after the first stop valve 2 is closed after the sampling is completed.

[0025] In practical applications, the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model has achieved at least the following beneficial technical effects, specifically:

[0026] 1) During the sampling process, the sampling pump 1 and the sampling pipeline matched with the sampling chamber 3 are always maintained in a negative pressure state, and after the sampling is completed, the sampling pump 1 and the sampling pipeline are isolated from the external environment, effectively preventing the intrusion of external debris, dust and other impurities. The sampling pump 1 and the sampling pipeline are always kept in a clean state, which is conducive to ensuring the purity of the sampled formaldehyde, and ultimately ensuring the accuracy of the subsequent quality inspection results;

[0027] 2) Under the negative pressure, the liquid formaldehyde head collected at the bottom of the sampling chamber 3 or the residual liquid formaldehyde caused by "leakage" is timely and properly collected into the waste liquid storage tank 6, thereby effectively avoiding the occurrence of formaldehyde contamination of the workshop floor or gaseous formaldehyde causing adverse effects on the atmospheric environment; in addition, due to the negative pressure, after the sampling is completed, a large amount of formaldehyde will not remain inside the sampling pump 1 and the sampling pipeline, which means that it is difficult for the pipeline to be blocked;

[0028] It should also be noted here that, in extreme cases, even if it is necessary to use low-pressure steam to purge the sampling pump 1 and the sampling tube matching the sampling chamber 3 after sampling, the formaldehyde gas phase is still sucked into the waste liquid storage tank 6 under the action of negative pressure, and will not evaporate into the surrounding atmospheric environment.

[0029] As is known, according to design common sense, the negative pressure generating unit 7 can be designed in a variety of ways to keep the liquid storage chamber of the waste liquid storage tank 6 stably in a negative pressure state. However, a scheme with a simple design structure, easy implementation, and relatively low power consumption is recommended here, specifically: Figure 1As shown in , the negative pressure generating unit 7 is mainly composed of a centrifugal pump 71 and a jet pump 72. The jet pump 72 and the centrifugal pump 71 are respectively arranged at the upstream and downstream of the waste liquid storage tank 6, and are supplemented by pipelines to form a liquid formaldehyde circulation loop, and the sampling chamber 3 is connected to one side of the jet pump 72. During the sampling process, the centrifugal pump 71 is maintained in the on state, and the formaldehyde waste liquid temporarily stored in the waste liquid storage tank 6 flows through the centrifugal pump 71 and the jet pump 72 in sequence and flows back to the waste liquid storage tank 6. At the same time, the jet pump 72 forms a negative pressure in its working chamber based on the Bernoulli principle. At the same time, the sampling chamber of the sampling chamber 3 is also maintained in a negative pressure state, so that the liquid formaldehyde head or excess liquid formaldehyde collected at the bottom of the sampling chamber 3 can be drained to the waste liquid storage tank 6 under the action of negative pressure, and the gaseous formaldehyde generated during the sampling process will not volatilize into the external environment.

[0030] At the beginning of the project, the negative pressure value of the sampling chamber of the sampling chamber 3 was extremely stable. In serious cases, it was even far lower than the initial design value. The reason is that since the waste liquid storage tank 6 is cleaned in time, its liquid storage chamber inevitably retains a large amount of impurities and foreign matter. When the centrifugal pump 71 is turned on, under the action of the pumping force, impurities, foreign matter, etc. are pumped into the centrifugal pump 71 and the jet pump 72, thereby causing the flow path to be narrow or blocked. In view of this, as a further optimization of the above technical solution and as a small technical transformation project of the workshop, a filter cover 61 is provided inside the waste liquid storage tank 6. The filter cover 61 is used to filter impurities from the liquid formaldehyde head or excess liquid formaldehyde pre-circulated to the centrifugal pump 71, and it is detachably fixed on the inner wall of the waste liquid storage tank 6. The mesh number of the filter cover 61 should be controlled at 200-250.

[0031] In the process of promoting technical reform, the design structure of the sampling chamber 3 has also been optimized and improved, specifically: Figure 3 As shown in the figure, the sampling bin 3 is mainly composed of a bin shell 31, a sampling conduit 32, and a mesh plate 33. Among them, the bin shell 31 is made of stainless steel and presents a variable-caliber funnel shape, and a material intake port 311 is opened on its side wall for the sampling barrel 4 to pass freely. The sampling conduit 32 is used to guide the liquid formaldehyde that flows through the main pipeline to the sampling bin 3, and it is inserted on the top wall of the bin shell 31. The mesh plate 33 is used to place the sampling barrel 4, which is placed horizontally in the cavity of the bin shell 31 and is located directly below the sampling conduit 32. In this way, the traditional open sampling method is abandoned, and the sampling barrel 4 is placed in a restricted small environment. On the one hand, it is conducive to the rapid formation and long-term maintenance of the negative pressure environment for sampling, thereby effectively avoiding the occurrence of gaseous formaldehyde overflow and environmental pollution during the sampling process; on the other hand, liquid formaldehyde head or excess liquid formaldehyde caused by leakage is collected at the bottom of the bin shell 31, which is conducive to its subsequent proper collection in the waste liquid storage tank 6 under the action of negative pressure to avoid contamination of the workshop floor.

[0032] Furthermore, by the attached Figure 3 It can also be clearly known from the figure that the sampling chamber 3 is also equipped with a side door mechanism, and its main structure is a side door 34, an upper hinge 35 and a lower hinge 36. The side door 34 is assembled with the side wall of the sampling chamber 3 by means of the upper hinge 35 and the lower hinge 36, and can freely perform rotation when subjected to push and pull forces, so that the material taking port 311 can be blocked or opened. When the sampling operation is pre-executed, the side door 34 is pulled to open it, and it is ensured to be in an open state, and the sampling barrel 4 smoothly passes through the material taking port 311 to be placed on the mesh plate 33. Then, the side door 34 is closed in time to form a small environment conducive to the formation of negative pressure, and then, the sampling pump 1, the centrifugal pump 71 and the jet pump 72 are turned on at the same time, and the sampling operation is implemented.

[0033] In order to ensure that the sampling bucket 4 occupies the correct position relative to the sampling conduit 32 after the mesh plate 33 is placed, and further ensure that the formaldehyde is collected in sufficient quantity, as a further optimization of the above technical solution, the sampling chamber 3 is further provided with a limiting ring 37. The limiting ring 37 is used to ensure that the placed sampling bucket 4 and the sampling conduit 32 remain aligned, and the limiting ring 37 is placed on and fixed to the top wall of the mesh plate 33.

[0034] Figure 4 The schematic diagram of the structure of the second embodiment of the environmentally friendly liquid formaldehyde negative pressure sampling system disclosed in the utility model is shown. The centrifugal pump 71 and the jet pump 72 are cancelled, and the waste liquid storage tank 6 is vacuumed by the vacuum generator 73 alone, so that the sampling chamber of the sampling chamber 3 is kept in a negative pressure state. The vacuum generator 73 uses the top wall or side wall of the waste liquid storage tank 6 as the installation reference. Compared with the first embodiment mentioned above, its design structure is extremely simple, easier to implement and maintain, and the specific application effect will continue to be demonstrated after the company's project is actually implemented.

[0035] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An environmentally friendly liquid formaldehyde negative pressure sampling system, characterized in that: The invention comprises a sampling pump, a first stop valve, a sampling chamber, a sampling barrel, a second stop valve, a waste liquid storage tank and a negative pressure generating unit; under the pumping force of the sampling pump, liquid formaldehyde flows to the sampling chamber via the main pipeline and the first stop valve in sequence, and in a certain time period, the sampling barrel placed in the sampling cavity of the sampling chamber can realize the liquid formaldehyde sampling operation, and in another time period, the liquid formaldehyde head or the liquid formaldehyde residue is collected at the bottom of the sampling chamber; the waste liquid storage tank is connected with the sampling chamber; the negative pressure generating unit is matched with the waste liquid storage tank so that its liquid storage cavity is always kept in a negative pressure state, and concomitantly, the sampling cavity of the sampling chamber is also maintained in a negative pressure state, and the liquid formaldehyde head or the liquid formaldehyde residue collected at the bottom of the sampling chamber can flow to the waste liquid storage tank via the second stop valve under the action of negative pressure to complete the collection.

2. The environmentally friendly liquid formaldehyde negative pressure sampling system according to claim 1 is characterized in that: The negative pressure generating unit is a vacuum generator, and the top wall or the side wall of the waste liquid storage tank is used as an installation reference.

3. The environmentally friendly liquid formaldehyde negative pressure sampling system according to claim 1 is characterized in that: The negative pressure generating unit includes a centrifugal pump and a jet pump; the jet pump and the centrifugal pump are respectively arranged at the upstream and downstream of the waste liquid storage tank, and are assisted by pipelines to form a liquid formaldehyde circulation loop, and the sampling chamber is connected to the jet pump; during the sampling process, the centrifugal pump is maintained in the on state, and the formaldehyde waste liquid temporarily stored in the waste liquid storage tank flows through the centrifugal pump and the jet pump in sequence and then flows back to the waste liquid storage tank. At the same time, the jet pump forms a negative pressure in its working chamber based on the Bernoulli principle, and the liquid formaldehyde head or excess liquid formaldehyde collected at the bottom of the sampling chamber can be drained to the waste liquid storage tank under the action of negative pressure.

4. The environmentally friendly liquid formaldehyde negative pressure sampling system according to claim 3 is characterized in that: A filter cover is provided inside the waste liquid storage tank; the filter cover is used to filter impurities from the liquid formaldehyde head or liquid formaldehyde residue pre-circulated into the centrifugal pump, and is detachably fixed to the inner wall of the waste liquid storage tank.

5. The environmentally friendly liquid formaldehyde negative pressure sampling system according to any one of claims 1 to 4, characterized in that: The sampling bin includes a bin shell, a sampling conduit and a mesh plate; the bin shell is in the shape of a variable-caliber funnel, and a material intake port is provided on its side wall for the sampling barrel to pass freely; the sampling conduit is used to guide the liquid formaldehyde flowing through the main pipeline to the sampling bin, and it is inserted on the top wall of the bin shell; the mesh plate is used to place the sampling barrel, which is placed horizontally in the cavity of the bin shell and is located directly below the sampling conduit.

6. The environmentally friendly liquid formaldehyde negative pressure sampling system according to claim 5, characterized in that: The sampling bin also includes a side-opening door, an upper hinge and a lower hinge; the side-opening door is assembled with the side wall of the sampling bin by means of the upper hinge and the lower hinge, and can freely rotate when subjected to push and pull forces, so that the material taking port can be blocked or opened.

7. The environmentally friendly liquid formaldehyde negative pressure sampling system according to claim 5, characterized in that: The sampling chamber also includes a limiting ring; the limiting ring is used to ensure that the placed sampling barrel and the sampling conduit remain aligned, and the limiting ring is placed on and fixed to the top wall of the mesh plate.

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