Membrane filter to prevent negative pressure air pollution

Abstract

The present invention relates to a membrane filter for preventing negative pressure air supply pollution, comprising a shell and a seat connected to the lower end of the shell, the seat and the shell enclose a container cavity, the upper end of the shell is provided with a liquid inlet for liquid to enter the container cavity, the seat is provided with a liquid discharge port for liquid to discharge from the container cavity, the container cavity is provided with a filter membrane between the liquid discharge port and the container cavity, the seat is provided with a negative pressure cavity for connecting to a suction filtration device, the liquid discharge port is connected to the negative pressure cavity, and the seat is provided with a first air filter capable of replenishing air to the negative pressure cavity. The present invention can use a negative pressure method to collect bacteria for culture, and by setting a first air filter, negative pressure air supply pollution can be prevented; by reasonably setting a vent, an air pipe and a sampling needle, while preventing negative pressure air supply pollution, bacteria collection and culture can be better achieved. At the same time, the membrane filter for preventing negative pressure air supply pollution of the present invention can also be used to detect microbial limits in liquid samples.

Description

Technical Field

[0001] The invention relates to a membrane filter, in particular to a membrane filter capable of preventing pollution from negative pressure air replenishment. Background Art

[0002] The membrane filtration method of sterility testing in Part IV of the Chinese Pharmacopoeia 2020 stipulates: The membrane filtration method should generally use a membrane filter, and the filter membrane material should be selected according to the characteristics of the test sample and its solvent. The pore size of the filter membrane used for sterility testing should not be greater than 0.45 microns. The diameter of the filter membrane is about 50mm. If a filter membrane of other sizes is used, the volume of the diluent and flushing solution should be adjusted and re-verified. When using, the integrity of the filter membrane before and after filtration should be ensured.

[0003] In the prior art, a bacterial culture vessel is usually used to perform sterility testing experiments using the membrane filtration method. Under sterile conditions, the prepared liquid sample is injected into the bacterial culture vessel under pressure, and then pressure is applied or simultaneously applied to filter it. If there are bacteria in the liquid sample, they will be trapped on the filter membrane, and then added to the broth culture medium for culture testing. Bacteria will grow, and bacterial growth will make the broth culture medium turbid and easy to identify, which means the sterility test fails. On the contrary, if there are no bacteria on the filter membrane, they grow aseptically in the broth culture medium, and the broth culture medium is clear, then the sterility test passes.

[0004] In the prior art, liquid samples and broth culture medium are generally injected into the culture vessel by positive pressure. The disadvantage of positive pressure is that it is difficult to complete the injection in one go and the pressure is not easy to control. If the pressure is too high due to careless operation, the culture vessel may burst and splatter, which may pollute the environment at the least and injure the operator at the worst.

[0005] If negative pressure is used, the incubator needs to be connected to the filtration device. When the operation is completed, the incubator needs to be removed from the filtration device. At this time, the negative pressure at the connection between the incubator and the filtration device must be eliminated before the incubator can be removed. However, if the negative pressure is eliminated by replenishing the pressure through the filtration device, it will cause pollution hazards, because the gas replenished by the filtration device will inevitably bring liquid, aerosol, water mist, etc. into the exposed areas such as the drainage pipe and base of the filtration device, and return from the drainage port of the incubator to the incubator, causing contamination, so that the sample of the bacterial culture may have a false positive and lead to misjudgment. Summary of the invention

[0006] The purpose of the present invention is to provide a membrane filter for preventing negative pressure air supplementation pollution, so as to alleviate or eliminate at least one of the above-mentioned technical problems.

[0007] A membrane filter for preventing pollution from negative pressure air replenishment described in the present invention comprises a shell and a seat body connected to the lower end of the shell, the seat body and the shell form a container cavity, the upper end of the shell is provided with a liquid inlet for liquid to enter the container cavity, the seat body is provided with a liquid discharge port for liquid to discharge from the container cavity, a filter membrane is provided in the container cavity between the liquid discharge port and the container cavity, a negative pressure cavity for connecting to a suction filtration device is provided on the seat body, the liquid discharge port is connected to the negative pressure cavity, and a first air filter capable of replenishing air to the negative pressure cavity is provided on the seat body.

[0008] Furthermore, it also includes a control structure for controlling the on and off of the first air filter.

[0009] Furthermore, the shell is a cylindrical member with openings at both upper and lower ends.

[0010] Furthermore, the shell includes a cylinder with openings at both ends and a closing structure for closing the opening at the upper end of the cylinder. The seat body is connected to the lower end of the cylinder, and the closing structure is a top wall of the shell that is integrally connected to the cylinder or a cover that is detachably connected to the upper end of the cylinder.

[0011] Furthermore, a vent is provided on the top of the shell, and the vent is connected to the air inlet end of the first air filter through an air pipe.

[0012] Furthermore, a second air filter is installed at the vent, and the air pipe is connected to the vent through the second air filter.

[0013] Furthermore, the seat body is eccentrically arranged relative to the shell, and the first air filter is arranged at a position of the seat body deviating from the shell.

[0014] Furthermore, the seat body is provided with a connecting tube extending downward, the connecting tube surrounds the negative pressure chamber, and the connecting tube is used to be connected to the filtration equipment.

[0015] Furthermore, it also includes a sealing cap which is detachably mounted on the input end of the first air filter.

[0016] Furthermore, it also includes a sampling tube connected to the liquid inlet, and the top of the shell is provided with a protrusion for interference fit with the sampling tube.

[0017] The present invention can use negative pressure to collect bacteria and cultivate. By setting a first air filter, it is convenient to remove and prevent negative pressure air pollution. By reasonably setting the vent, trachea and sampling needle, it is possible to better achieve bacteria cultivation while preventing negative pressure air pollution. At the same time, the membrane filter for preventing negative pressure air pollution of the present invention can also be used to detect the microbial limit in liquid samples. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the membrane filter for preventing negative pressure air supply pollution described in Example 1;

[0019] Figure 2 for Figure 1 A partial enlarged view of

[0020] Figure 3 It is a schematic diagram of the structure of the membrane filter for preventing negative pressure air supply pollution described in Example 2;

[0021] Figure 4 for Figure 3 A partial enlarged view of

[0022] Figure 5 This is a schematic diagram of the structure of the membrane filter for preventing negative pressure air replenishment pollution described in Example 3.

[0023] In the figure: 1—seat body; 2—negative pressure chamber; 3—liquid discharge port; 4—connecting cylinder; 5—through hole; 6—first air filter; 7—housing; 8—filter membrane; 9—film pressing ring; 10—liquid inlet; 11—sampling tube; 12—air vent; 13—second air filter; 14—trachea; 15—tube clamp; 16—sampling needle; 17—third air filter; 18—cylinder body; 19—cover; 20—first retaining ring; 21—second retaining ring; 22—raised portion; 23—sealing cap. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Embodiment 1

[0026] like Figure 1 and Figure 2The membrane filter for preventing negative pressure air replenishment pollution shown in the figure comprises a shell 7 and a seat body 1 connected to the lower end of the shell 7, the seat body 1 and the shell 7 enclose a container cavity, the upper end of the shell 7 is provided with a liquid inlet 10 for liquid to enter the container cavity, the seat body 1 is provided with a liquid discharge port 3 for liquid to discharge from the container cavity, the container cavity is provided with a filter membrane 8 between the liquid discharge port 3 and the container cavity, the seat body 1 is provided with a negative pressure cavity 2 for connecting to a suction filter device, the liquid discharge port 3 is connected to the negative pressure cavity 2, and the seat body 1 is provided with a first air filter 6 capable of replenishing air to the negative pressure cavity 2. The first air filter 6 can transport clean air to the negative pressure cavity 2, eliminate pressure by replenishing air, and eliminate the negative pressure at the connection between the seat body 1 and the suction filter device, and can be conveniently removed to prevent the liquid in the suction filter device (sterility cannot be guaranteed) from forming water mist or aerosol during air replenishment and backwashing from the liquid discharge port 3 into the membrane filter for preventing negative pressure air replenishment pollution and causing pollution. In this embodiment, the structure of the first air filter 6 can adopt but is not limited to the medical air filter in the prior art, such as the air filter commonly used in the infusion system.

[0027] In this embodiment, the top of the housing 7 is further provided with an air vent 12, which is connected to the air inlet end of the first air filter 6 through an air pipe 14. The air in the container cavity can be extracted through the air pipe 14 to form a negative pressure, and can be used together with the filter membrane 8 through which air cannot pass; and the air can be delivered to the first air filter 6 through the air pipe 14.

[0028] In this embodiment, a second air filter 13 is installed at the vent 12, and the air pipe 14 is connected to the vent 12 through the second air filter 13, and the second air filter 13 can filter the gas entering and exiting the vent 12. One end of the air pipe 14 is connected to the first air filter 6, and the other end of the air pipe 14 is connected to the second air filter 13.

[0029] In this embodiment, the membrane filter for preventing negative pressure air supplementation pollution further includes a control structure for controlling the on-off of the first air filter 6. The control structure may be a pipe clamp 15 disposed on the air pipe 14, and the air pipe 14 may be a hose, and the pipe clamp 15 is used to control the on-off of the air pipe 14, thereby controlling the on-off of the first air filter 6.

[0030] In this embodiment, the seat body 1 is provided with a connecting tube 4 extending downward, the connecting tube 4 encloses the negative pressure chamber 2, and the smooth lower edge of the connecting tube 4 is used to connect with the sealing ring of the cup seat of the suction filtration device or the cup seat sealing ring on the conversion head connected to the suction filtration head of other equipment. The suction filtration device can be selected from but not limited to the fully automatic membrane filtration suction filter described in the Chinese patent application with application number CN201720853552.6.

[0031] In this embodiment, in order to facilitate the arrangement of the first air filter 6, the seat body 1 is eccentrically arranged relative to the housing 7, and the first air filter 6 is arranged at a portion of the seat body 1 that deviates from the housing 7, and the first air filter 6 is arranged outside the housing. In specific implementation, a through hole 5 is provided at a portion of the seat body 1 that deviates from the housing 7, and the first air filter 6 is installed in the through hole 5, and the output end of the first air filter 6 is communicated with the negative pressure chamber 2, and the output end of the first air filter 6 is located outside the seat body 1.

[0032] In this embodiment, a sampling needle 16 and a sampling tube 11 are also included. The sampling needle 16 is connected to the liquid inlet 10 through the sampling tube 11. The sampling needle 16 is provided with a sampling needle head, an air intake needle head and a third air filter 17. The sampling needle head is connected to the sampling tube 11, and the air intake needle head is connected to the air outlet end of the third air filter 17. The air intake end of the third air filter 17 is connected to the outside of the sampling needle 16, which can replenish sterile air into the container cavity to eliminate the negative pressure formed by drawing and adding samples. When not in use, the sampling needle 16 is equipped with a protective cover for protecting the sampling needle head and the air intake needle head.

[0033] In this embodiment, a protrusion 22 for interference fit with the sampling tube 11 is provided on the top of the shell 7. The membrane filter for preventing negative pressure air supply pollution can be pulled out from the filtration equipment, the sampling tube 11 can be shortened, and the broken end of the sampling tube 11 can be put on the protrusion 22, and the protrusion 22 is used to seal the broken end of the sampling tube 11.

[0034] In this embodiment, in order to fix the position of the filter membrane 8, the filter membrane 8 is supported on the base body 1, and a membrane pressing ring 9 for pressing the filter membrane 8 downward is provided in the housing 7. Furthermore, a filter pad is provided between the filter membrane 8 and the base body 1, and the filter pad can prevent the filter membrane 8 from directly contacting the supporting surface on the base body 1, eliminating the possibility of indentation on the filter membrane 8, and on the other hand, the filter pad can play the role of elastic support.

[0035] In this embodiment, if Figure 1 As shown, the housing 7 includes a cylinder with openings at both ends, and the seat 1 is connected to the lower end of the cylinder. The housing 7 also includes a closing structure for closing the opening at the upper end of the cylinder. The closing structure is a housing top wall connected to the cylinder as a whole. The liquid inlet 10 and the vent 12 are both arranged on the housing top wall. The housing top wall and the cylinder can be formed in an integral manner. The housing 7 of this structure has good sealing performance.

[0036] The working principle of the membrane filter for preventing negative pressure air supply pollution is as follows:

[0037] First, install the membrane filter for preventing negative pressure air supplementation pollution on the filtration device, insert the sampling needle and the air inlet needle of the sampling needle 16 into the sample bottle containing the liquid sample, turn on the filtration device, extract the air in the container cavity through the negative pressure cavity 2, the first air filter 6, the air pipe 14, the second air filter 13 and the vent 12, form a negative pressure in the container cavity, and use the negative pressure to extract the liquid sample in the sample bottle into the container cavity;

[0038] After the liquid sample is injected, the liquid sample soaks the filter membrane 8, and the tube clamp 15 can be closed to filter the liquid sample using the negative pressure at the drain port 3. If there are bacteria in the liquid sample, the bacteria will be trapped on the filter membrane 8.

[0039] After the filtration is completed, the filtration device is turned off, the sampling needle and the air inlet needle of the sampling needle 16 are inserted into the culture medium bottle containing the liquid culture medium (e.g., broth culture medium), the membrane filter for preventing negative pressure gas replenishment pollution is removed, the discharge port 3 is plugged with a plug, and the membrane filter for preventing negative pressure gas replenishment pollution is placed back on the cup holder of the filtration device, and then the tube clamp 15 is opened, and the filtration device is turned on to form a negative pressure in the container cavity, and the liquid culture medium in the culture medium bottle is extracted into the container cavity by using the negative pressure;

[0040] After the liquid culture medium is extracted, the clean air input through the third air filter 17 flows through the air inlet needle, culture medium bottle, sampling needle, sampling tube 11, container cavity, vent 12, second air filter 13, trachea 14 and first air filter 6 in sequence. The clean air output by the first air filter 6 flows into the negative pressure chamber 2, thereby eliminating the negative pressure at the connection between the seat body 1 and the filtration device. Then the membrane filter for preventing negative pressure air replenishment pollution can be easily removed from the filtration device, which can prevent pollutants in the negative pressure air replenishment process from rebounding from the discharge port 3 to the inside of the membrane filter for preventing negative pressure air replenishment pollution.

[0041] It can be seen from the above working process that by setting the air pipe 14 in conjunction with the tube clamp 15, the negative pressure chamber 2 can be connected to the negative pressure to smoothly complete the sample addition, filtration, culture medium addition and extraction of the membrane filter for preventing negative pressure air supplementation pollution, which has the advantage of simple operation. In specific implementation, the membrane filter for preventing negative pressure air supplementation pollution of the present invention can be made into a disposable product.

[0042] Embodiment 2

[0043] like Figure 3 and Figure 4As shown, the difference between this embodiment and the first embodiment is that the structure of the shell is different. In this embodiment, the closed structure of the shell is a cover 19 connected to the upper end of the cylinder 18 in a detachable manner, and the seat 1 is connected to the lower end of the cylinder 18 in a detachable manner. The liquid inlet 10 and the vent 12 are both arranged on the cover 19. The membrane filter for preventing negative pressure air replenishment pollution using this structure can also be used to detect the microbial limit in the liquid sample. As a preferred embodiment, the lower end of the cylinder 18 is provided with a first clamping ring 20 protruding inwardly, and the seat 1 is provided with a connecting portion that matches the lower end of the cylinder 18. The outer side wall of the connecting portion is provided with a second clamping ring 21 protruding outwardly. The first clamping ring 20 is clamped on the lower side of the second clamping ring 21, and the first clamping ring 20 presses against the second clamping ring 21 upwardly to detachably connect the lower end of the cylinder 18 and the seat 1 together.

[0044] Embodiment 3

[0045] like Figure 5 A membrane filter for preventing negative pressure air replenishment pollution is shown, comprising a shell 7 and a seat body 1 connected to the lower end of the shell 7, the seat body 1 and the shell 7 form a container cavity, the upper end of the shell 7 is provided with a liquid inlet 10 for liquid to enter the container cavity, the seat body 1 is provided with a liquid discharge port 3 for liquid to discharge from the container cavity, the container cavity is provided with a filter membrane 8 between the liquid discharge port 3 and the container cavity, the seat body 1 is provided with a negative pressure cavity 2 for connecting to a suction filtration device, the liquid discharge port 3 is also connected to the negative pressure cavity 2, and the seat body 1 is provided with a first air filter 6 capable of conveying air to the negative pressure cavity 2. In the present embodiment, a sealing cap 23 is also included which is detachably mounted on the input end of the first air filter 6. The sealing cap 23 can seal the input end of the first air filter 6. After the sealing cap 23 is removed, the first air filter 6 can deliver clean air to the negative pressure chamber 2, and eliminate the pressure by replenishing air to eliminate the negative pressure at the connection between the seat body 1 and the suction filter device. The membrane filter that prevents the pollution of negative pressure replenishing air can be easily removed, and the liquid in the suction filter device (which cannot be guaranteed to be sterile) can be prevented from forming water mist or aerosol from the discharge port 3 during the replenishing air to backwash into the membrane filter that prevents the pollution of negative pressure replenishing air and causing pollution. In the present embodiment, the housing 7 is a cylindrical member with openings at both ends, and the upper end opening of the housing 7 is the liquid inlet 10. The housing 7 with such a structure can form an open membrane filter that prevents the pollution of negative pressure replenishing air.

Claims

1. A membrane filter for preventing negative pressure air supply pollution, characterized in that: The invention comprises a shell (7) and a seat body (1) connected to the lower end of the shell (7), wherein the seat body (1) and the shell (7) enclose a container cavity, wherein the upper end of the shell (7) is provided with a liquid inlet (10) for liquid to enter the container cavity, the seat body (1) is provided with a liquid discharge port (3) for liquid to discharge from the container cavity, the container cavity is provided with a filter membrane (8) separated between the liquid discharge port (3) and the container cavity, the seat body (1) is provided with a negative pressure cavity (2) for connecting to a suction filtration device, the liquid discharge port (3) is connected to the negative pressure cavity (2), and the seat body (1) is provided with a first air filter (6) capable of replenishing air to the negative pressure cavity (2); It also includes a control structure for controlling the on and off of the first air filter (6); The shell (7) comprises a cylinder (18) with openings at both upper and lower ends and a closing structure for closing the opening at the upper end of the cylinder (18); the seat (1) is connected to the lower end of the cylinder (18); the closing structure is a top wall of the shell integrally connected to the cylinder (18) or a cover (19) detachably connected to the upper end of the cylinder (18); The top of the housing (7) is also provided with an air vent (12), and the air vent (12) is connected to the air inlet end of the first air filter (6) through an air pipe (14); A second air filter (13) is installed at the vent (12), and the air pipe (14) is connected to the vent (12) through the second air filter (13).

2. The membrane filter for preventing negative pressure air supply pollution according to claim 1 is characterized in that: The seat body (1) is eccentrically arranged relative to the shell body (7), and the first air filter (6) is arranged at a position on the seat body (1) that deviates from the shell body (7).

3. The membrane filter for preventing negative pressure air supply pollution according to claim 1 is characterized in that: The seat body (1) is provided with a connecting tube (4) extending downwards, the connecting tube (4) enclosing the negative pressure chamber (2), and the connecting tube (4) is used to be connected to a suction filtration device.

4. The membrane filter for preventing negative pressure air supply pollution according to claim 1 is characterized in that: It also includes a sealing cap (23) which is detachably mounted on the input end of the first air filter (6).

5. The membrane filter for preventing negative pressure air supply pollution according to claim 1, characterized in that: It also comprises a sampling tube (11) connected to the liquid inlet (10), and the top of the housing (7) is provided with a protrusion (22) for interference fit with the sampling tube (11).

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