What’s The Role Of Solvent Filter Played In Vacuum Filtration?

 What's The Role Of Solvent Filter Played In Vacuum Filtration?

Vacuum filtration apparatus is mainly used in liquid chromatography mobile phase filtration, particle matter analysis, and microbial contamination detection. They are standing equipment in chemical laboratories. Use borate glass or 316L sanitary stainless steel as the material, which can filter various aqueous solutions, organics, and corrosive liquids in the analysis, and can be autoclaved at 121°C.

HAWCH vacuum filtration apparatus includes vacuum filtration and vacuum pump. As an indispensable part of vacuum filtration, the solvent filter is a small device that removes a small number of solid particles in the liquid, which can protect the normal operation of the device. When the fluid enters the filter cartridge with a certain filter screen, its impurities are blocked, and the clean filtrate is discharged from the filter outlet. When cleaning is needed, just take out the detachable filter cartridge and reinstall it after treatment.

Solvent filter is suitable for precision filtration of solid and liquid in grease, petrochemical, pharmaceutical, pesticide, paint, food and beverage, chemical fiber, and wastewater.

Solvent filter operations
1. The solvent filter is fragile, so it must not be moved as a whole, especially with a clip.
2. The filter membrane must be qualified, and the unqualified ones will dissolve impurities. The solvent to be filtered can be soaked for 24 hours to see if there is any dissolution, so as to inspect the quality of the filter membrane.
3. The filter membrane is divided into organic and water systems, which should be distinguished.
4. For water filtration, organic membranes are used for organic membranes, and then mixed after filtration. For the mixed mobile phase, the membrane of a higher ratio should be used.
5. The membrane does not matter anyway, but the smooth side is up, and the rough side is down.
6. Do not discard the waste filter membrane at will. The filter membrane pollutes the environment and should not be solved. Collect for unified processing.
7. When pumping air with the oil-free vacuum pump supporting the solvent filter, do not wait for the liquid to be empty before pulling out the hose. It is not suitable to pull out, it will squash the hose and stop the pump when there is a little liquid left.
8. The filtered solvent should avoid secondary pollution.

Notes in the use of solvent filter

1. The flow capacity of the filter should be greater than 2 times the flow during normal operation;
2. When selecting a filter, pay attention to the reasonable selection of the filter;
3. Taboo oil flows in both directions in the filter;
4. The precision of the suction filter should not be too high;
5. The filter set in the pipeline should have a blockage alarm device;
6. The flow capacity of the return oil filter cannot be simply selected according to the pump flow;
7. When using water glycol media, a special filter must be selected.

Solvent filter maintenance

1. When installing the filter, pay attention to the direction of liquid flow marked on the housing, and install it in the hydraulic system correctly;
2. When the filter pressure difference indicator shows a red signal, clean or replaces the filter in time;
3. The filter should be cleaned or replaced regularly, and external contaminants should be prevented from entering the working system during cleaning and replacement;
4. When the filter is cleaned, the port should be blocked to prevent the cleaned dirt from entering the inner cavity of the filter and causing internal pollution;
5. Solvent filter failures are generally due to clogging of the filter or deformation, bending, flattening, and breakdown of the filter, etc. The repair method is to clean or replace the filter.

 What's The Role Of Solvent Filter Played In Vacuum Filtration?

Introduction Of Glass Fiber Extraction Thimbles

 Introduction Of Glass Fiber Extraction Thimbles

The glass fiber extraction thimbles are made of high-grade special ultra-fine glass wool and carefully processed by a special process. It is a high-efficiency filter device that collects harmful substances such as smoke, acid mist, and beryllium substitutes. Glass fiber extraction thimbles has the advantages of high-temperature resistance, low weight loss, high efficiency, and good strength.

Technical indicators

Temperature resistance: can withstand below 600 ℃. Resistance: 14-20mmHg. Efficiency: 99.9999% (for dust particles with a particle size ≥ 0.3 ч). Weight loss: 0.2%. The current extraction thimbles are all glass fiber (applicable below 400 degrees).

The weight must be weighed before the boiler dust sampling. In this process, it is best to dry and weigh in small batches. Because if it is a large batch, the opening and closing of the dryer cover during the weighing process will inevitably make it absorb moisture, which will increase the blank value and cause the measurement result to below.

Punching problem

Generally, there are two areas of the test hole that are not punched. One is on the horizontal pipe, in front of the base of the vertical chimney, and the other is on the vertical chimney. When the cross-sectional area of the flue is constant, it is considered that the location of the test hole is the same everywhere.

Because after the flue gas passes through the dust collector, the remaining part is only a part of the particulate smoke and the cold rail coil, so in the case of constant airflow, it generally cannot be completely settled.

For example, during a monitoring process, the glass screen printing machine, due to the opening of the plug, vibrated a part of iron filings. During the test process, I found that there were some iron filings in the extraction thimbles. Just imagine that the iron filings cannot be settled, not to mention the small Where’s the smoke? Therefore, when the cross-sectional area of the flue remains unchanged, the location of the test hole has little effect on the test result.

Of course, if there is a significant change in the cross-sectional area of the flue after the dust collector, it is better to punch the test hole at the end where the cross-sectional area of the flue becomes larger because this can make use of the larger cross-sectional area of the flue and slower airflow. Precipitating a part of smoke and dust, making the test result smaller.

What are the operating conditions of the glass fiber extraction thimbles?

Due to the characteristics of glass fiber, the following points must be paid attention to when using it. Before use, check that the two sampling heads are slightly blocked, slightly hooped, whether the taper is the same, matching, and the clearance is appropriate. When the extraction thimbles are loaded and unloaded, it is not affected by the force of tearing, shearing, etc., so that the extraction thimbles mouth is not broken.

If the glass fiber extraction thimbles are found to have voids, cracks, or uneven thickness, it cannot be used to avoid being blown by the airflow and causing sampling failure. It should be used within the specified temperature range to ensure that the extraction thimbles works under sufficient strength.

According to reports, when the glass fiber is heated to above 200°C and then cooled, its strength begins to drop continuously. After the fiber is heated to 510°C and cooled, its strength only maintains 35% of its original strength. The fiber can maintain high strength when heated, but after cooling, its strength is greatly reduced.

The glass fiber extraction thimbles have been widely used in China since it was put into production in 1974. Due to the use of glass fiber extraction thimbles, my country’s smoke and dust detection work has been greatly improved.

 Introduction Of Glass Fiber Extraction Thimbles

Introduction Of Glass Fiber Extraction Thimbles

Guide to Selection Of Sample Vials Septa And Cap

Although the sample vial is small, it is very learned. When something goes wrong with our results, the vial is always the last thing we think about, but it’s the first step. When choosing the right vial for your application, you need to make three decisions: the septa, the lid, and the vial itself.

1. Guide to the selection of septa
PTFE
Recommended for a single injection. Excellent solvent resistance and chemical compatibility. No resealing after a puncture. Long-term sample storage is not recommended.

PTFE/silica gel
It is recommended for multiple injections and sample storage. Excellent reseal properties. Chemical resistance of PTFE before puncture, and chemical compatibility of silica gel after the puncture. The operating temperature ranges from -40°C to 200°C.

Precut PTFE/ silicone
Excellent sampling reproducibility is achieved by providing good ventilation to prevent a vacuum from forming in the sample vial. Eliminate the blockage of the needle at the bottom of the sample. Good resealing ability. It is recommended for multiple injections. The operating temperature ranges from -40 ℃ to 200 ℃. No isolation pad PE. It has the same advantages as PTFE.

2. Vial cap selection Guide
There are three types of cap for sample vials: crimp top cap, snap cap, and screw thread top cap. Each sealing method has its own advantages.

Pliers flap
The sealing effect is very good and can prevent the sample from evaporating effectively. The position of the septa shall remain unchanged when the automatic sampler is pricking through sampling. The capping device is needed to seal the sample vial with a clamp cap. For a small number of samples, a manual gland is the best choice. For large samples, an automatic gland can be used.

Bayonet cover
The bayonet cover is an extension of the clamp cover seal. The plastic cover on the edge of the sample vial creates a seal by squeezing the septa between the glass and the extended plastic cover. The tension of the plastic cap is caused by its attempt to regain its original size. This tension creates a seal between the glass, the vial cap, and the septa.

The plastic bayonet lid can be closed without any tools. The sealing effect of bayonet cover is not as good as the other two sealing methods. If the cap fits very tightly, it can be difficult to put on and may break. If it is too loose, the sealing effect will be poor and the septum may leave the original position.

Screw cap
The screw cap is universal. Tightening the cap exerts a mechanical force that squeezes the septa between the glass vial edge and the aluminum cap. In the process of puncture sampling, the screw cap has an excellent sealing effect and supports the septa by mechanical means.No tools are needed for assembly. The PTFE/ silica gel septa of the screw cap are fixed to the polypropylene vial cap by a non-solvent bonding process. The bonding technology is designed to ensure that the septa stay with the cap during transportation and when the cap is placed on the sample vial.

This bonding helps prevent the septa from falling off during use, but the main sealing mechanism is still the mechanical force applied when the cap is tightly wound onto the sample vial. The mechanism of vial cap tightening is to form a seal and to keep the septa in the correct position during the insertion of the sampling needle. Do not screw the cap too tightly, as this will affect the seal and cause the septum to fall off and translocate. If the cap is rolled too tightly, the septa can become cupped or dented.

Small sample vial has so much exquisite knowledge, so is it clearer?
With the wide application of chromatography in detection, a large number of chromatographic sample vials need to be cleaned in the detection process, which not only wastes time and reduces working efficiency, but also results in deviation of experimental results due to the fact that the cleanness of chromatographic sample vials after cleaning does not meet the requirements. Therefore, choosing the right way to clean the sample vial is crucial!

Plan 1
1. Pour dry the sample solution in the vial.
2. Soak all 95% alcohol, rinse twice with ultrasonic and pour dry, because alcohol can easily enter into 1.5mL vials and can be inter dissolved with most organic solvents to achieve.
3. Pour in water and wash with ultrasonic twice.
4. Dry the lotion in the vial and bake it at 110 degrees Celsius for 1 to 2 hours. Never bake it at high temperatures.
5. Cool and store.

Plan 2
1. Rinse under running water several times.
2. Put it into a beaker filled with pure water and ultrasonic for 15 minutes.
3. Change the water and ultrasonic for another 15 minutes.
4. Soak in a beaker filled with or without water-ethanol.
5. Take out and air dry naturally.

Plan 3
1. Soak in methanol (pure by chromatography) for 20 minutes with ultrasonic cleaning, and then pour the methanol dry.
2. Then fill the chromatographic sample vial with water, ultrasonic cleaning for 20 minutes, and then pour the water dry.
3. After that, the chromatographic sample vial is dried.

Plan 4
1. Generally is the first rinse with clean water after drying with sulfuric acid dichromate potassium lotion immersion.
2. First, use medical alcohol to soak for more than 4 hours, then ultrasonic for half an hour, then pour out medical alcohol, use water ultrasonic for half an hour, rinse with water, and then dry.

Plan 5
1. If the cost is sufficient, it is best to use a new one every time.
2. If it is to be reused, the cleaning method is also very important. Firstly, soak in strong oxidizing cleaning solution (potassium dichromate) for 24 hours, then clean it three times with deionized water under ultrasonic conditions, and finally clean it once with methanol and then dry it.
3. The vial pad must be replaced with a new one, especially when analyzing pesticide residues, otherwise, the quantitative results will be affected.

Guide to Selection Of Sample Vials Septa And Cap