How to Use and Maintain a Solvent Filter?

The solvent filter(300mL Glass Solvent Filter, 500ml Glass Solvent Filtration Apparatus) is mainly applied to the filtration of the aqueous phase, the organic phase, and the corrosive liquid for the analysis of specific contaminants. It can also be used for the aseptic test, culture sterilization filtration, and sterilization filtration of heat-sensitive substances. Today, HAWACH will discuss how to use and maintain it.


How to use a solvent filter?

1. Before use, you must know whether the filtering substance has any effect on the filter membrane, and choose the corresponding material of the membrane according to the type of filtering substance.
2. Clean the filter membrane with distilled water before use, and then soak it in 70℃~80℃ water for 4 hours, or soak it in room temperature distilled water for 12 hours.
3. The filter will be cleaned (stainless steel filters can be brushed with distilled water, glass filters without filter membrane, filtering operation with hexane or petroleum ether, and then rinse clean with distilled water filtration).
4. Place the soaked filter membrane in the middle of the membrane support net or glass sand core filter, and press the membrane with a filter funnel.
5. Clamp the anodized aluminum spring clip on the top and bottom flange sides.
6. Put the filter as a whole into the sterilization autoclave for steam hot-pressure sterilization treatment (121℃, 30 minutes), or other methods can be used. When hot-pressure sterilization, avoid direct one-way rush of steam on the filter membrane and prevent the membrane from breaking due to negative pressure from steam condensation.
7. Turn on the power of the vacuum pump( Standard Vacuum Filtration Pump, Anti-Corrosion Diaphragm Vacuum Pump), press the power switch, then there should be the sound of air pump operation, touch the pumping port with your hand should feel the pumping effect, see the pressure gauge shows normal, indicating that the vacuum pump is running normally.
8. Turn off the power and turn on the pressure regulator knob of the pressure reducer.
9. Connect the filter and vacuum pump with the rubber tube, pour the filtered medium into the filter cup, be careful not to be too full.
10. Press the power switch and adjust the pressure regulator knob of the pressure reducer to reach the required vacuum pressure, then start working.
11. After filtration, turn off the power switch and open the pressure regulator knob to return to normal pressure in the filter before separating the pump from the filter connection conduit.
12. After use, take out the filter membrane and clean and dry the solvent filter with pure water for the next use.

How to maintain it after a period of work?

HAWACH solvent filter unit is made of high-quality glass with high wall thickness uniformity. It is divided into three parts, the upper part is a cup-type grinding mouth container called a filter cup, the capacity is 300ml and 500ml; the middle is an inner grinding mouth support device with a spout, there is a flat grinding glass sand chip in the center for supporting the filter membrane, called filter head, the corresponding specifications are 1L and 2L; the lower part is an outer grinding mouth pressure resistant container called triangular bottle; the corresponding capacity is 1000ml and 2000ml. The corresponding volumes are 1000ml and 2000ml, and are equipped with aluminum alloy special clips for tight connection of the whole device, and the clips are oxidized to resist chemical corrosion. After the filter works for a period of time, the core of the filter precipitates certain impurities, and at this time the pressure drop increases and the flow rate decreases, so it is necessary to remove the impurities in the filter core in time.

If the purity of the filtered media can not reach the design requirements, compressors, pumps, meters and other equipment will be damaged. No matter what the filter is, it should be cleaned, and the method of its cleaning is reverse cleaning, or called reverse cleaning.

The following methods can effectively prevent the clogging of solvent filters:

1. Strictly enforce solvent filtration.
2. Do not use distilled water and phosphate buffer stored for many days.
3. Blow argon gas continuously at low flow rate above the solvent in the solvent bottle to isolate the air.
4. Avoid exposing the solvent bottle to direct sunlight, and try to use amber solvent bottle to hold aqueous solution or phosphate buffer.
5. After blockage, the method of treatment method: remove the filter head from the assembly, soak it in concentrated nitric acid (35%) for 1h, then rinse it well with secondary distilled water and ultrasonic treatment.