An Explanation Of The Vacuum Filtration

An overview of the Vacuum filtration is the most widely used and most mature filtration method in theory and practice.Like other filter cake filtration methods, vacuum filtration technology USES porous filter media to support the filter cake.The difference is that vacuum filtration USES less thrust, so it is suitable for some special applications.

Vacuum filtration is a continuous filtration operation of sludge waterproofing, usually done in a cylindrical rotary drum filter.The filter media covered on the drum can be natural fabric, synthetic fiber products or wire mesh. The drum is arranged horizontally on top of the sludge tank and partially immersed in the tank. When the rotary drum rotates slowly, part of the circumference of the rotary drum bears the internal vacuum and sucks the sludge to the media of the filter. The water in the sludge is sucked out in the rotation and the cement cake is scraped off. The wet sludge is usually conditioned in order for the vacuum filter to achieve good handling capacity.

The principle of vacuum filtration, is due to the role of the vacuum machine, in the filter drum of the filter into negative pressure, forming the pressure difference between the two sides of the filter media layer (press cloth). With the rotation of the filter, the mother liquor in the lye is removed, and the heavy alkali is absorbed on the press cloth, which is finally scraped off by the scraper.

Rotary vacuum filter
Its main body is a rotating horizontal cylinder, called a rotating drum, with a diameter of 0.3~4.5m and a length of 3~ 6m. The outer surface of the cylinder is composed of a porous plate or a special drainage member covered with a press cloth. The inside of the cylinder is divided into a number of fan-shaped compartments, each of which has a straw connected with a hole in the hollow shaft, and the hole in the hollow shaft leads axially to a rotating disk located at the end of the shaft and rotating with the shaft. The rotating disc and the fixing disc are closely matched to form a special rotary valve called the distribution head. The fixed disk of the distribution head is divided into several arc-shaped voids, which are connected with the pressure relief tube, the washing liquid storage tank, and the compressed air pipeline respectively.

When the drum rotates, the fan can obtain vacuum and pressure respectively by using the function of the distribution head, so that the filtration, washing and other operations can be controlled step by step.

Advantages of a rotary vacuum filter:
(1)Continuous production, the higher degree of mechanization;
(2)According to the nature of the material, process requirements, using different materials to manufacture various types, in order to meet different filtration requirements (usually, for the suspension of medium particle size, viscosity is not too big material, rotary drum vacuum filter is applicable);
(3)Filter cake thickness and washing effect can be controlled by adjusting rotating drum speed;
(4)The loss of press cloth is smaller than that of other types of filters.

Disadvantages of rotary drum vacuum filter:
(1)Filter force is small, it is only the use of vacuum as the driving force. Due to the pipeline resistance loss, the maximum is no more than 80kPa, generally 26.7-66.7kpa, so it is not easy to drain, the final humidity of the filter cake is generally more than 20%;
(2)Equipment processing and manufacturing complex, the main equipment and auxiliary vacuum equipment investment is expensive, high energy consumption in the vacuum, at the same time, the larger the filter area manufacturing more difficult. The maximum filtration area of domestic production is about 50, generally 5 ~ 40.

Rotary vacuum filter
As shown in the figure on the right is the schematic diagram of the rotary table vacuum filter. It consists of a set of filter plates (or turntables) mounted on a horizontal rotating shaft and rotating along the shaft. The structure and operating principle of the rotary disk vacuum filter are similar to that of a rotary drum vacuum filter.

Each sector of the disk has its own outlet pipe leading to the central axis, and when a number of disks are joined together, the outlet of the sector of a rotary disk forms a continuous channel with the corresponding outlet of the other rotary plates in the same phase Angle. Similar to a rotary drum vacuum filter, these continuous channels are connected to a shaft end rotary valve (distribution head). The operation of the rotary disk vacuum filter is very similar to that of a rotary drum vacuum filter. Each turntable is equivalent to a drum, and the operating cycle is also controlled by a rotary valve. Each rotary table has its own filter cake unloading device, but unloading is more difficult.

An Explanation Of The Vacuum Filtration

QuEChERS Extraction Salts And Ceramic Homogenizers

Normally, we add both organic solvents and buffer salts to the substrate when extracting the target, but when a sample with high water content is encountered, the buffer salt will have an exothermic reaction with water, thus affecting the recovery rate. Hawach provides a separate extraction salt package (pre-precision weighing, no water content), and the user can add the organic solvent and then choose to put the buffer salt. Hawach offers a variety of extracted salt kits that customers can choose from on demand.

Hawach offers extraction kits and dispersion solid-phase extraction purification kits, both of which can be applied to common fruits, vegetables, fruits and vegetables containing fat and wax, as well as colored fruits and vegetables. Customers can choose the dispersion solid phase extraction kit according to the type of food analyzed and the method used. For those laboratories that prepared test tubes, Hawach also provided bulk salts and adsorbents. Additionally, all the QuEChERS kits provided by Hawach are produced under strict ISO-9001 standards, including a wide range of polymers, silica gel and other adsorbents that can be selected.

Characteristic of QuEChERS Extraction Salts
The QuEChERS method is fast, simple and economical, and Hawach makes the QuEChERS program easier. Specialized glassware is not required when you use Hawach QuEChERS to pick up bags and tubes. The freely flowing extracted salt and salt packs were easily put into the extraction tube, making the salt easily transferred into the sample. It is easy to pack without a second tube for salt transfer. And the convenient slender packaging fits perfectly into the tube to prevent spillage.

Performance of QuEChERS Extraction Salts
Hawach QuEChERS extraction salt packs are used to provide suitable pH to ensure a good recovery of some alkali-sensitive pesticides. When the sample with high water content is encountered, the buffer salt will have an exothermic reaction with water, thus affecting the recovery rate. Biocoma provides a separate extraction salt package, and the user can add the buffer salt after adding the organic solvent to prevent the local overheating of the sample.

Main Function of QuEChERS Ceramic Homogenizers
Hawach QuEChERS ceramic homogenizers are mainly used in the preparation method of QuEChERS samples. The traditional extraction method requires a vigorous shaking sample for 1 min. at this time, the homogeneity and poor recovery may occur. In the process of sample extraction, the addition of homogeneous protons is beneficial to the uniformity of the sample extraction process and to improve the recovery rate of the detected compounds.

Design Feature of QuEChERS Ceramic Homogenizers
The QuEChERS ceramic homogenizer has the following characteristics: it use inert material and causes no impurity dissolution; the sample extraction time was shortened. Meanwhile, it can prevent the extraction salt from caking, ensure the reproducibility of extraction process, enhance recovery of test results, and improve the efficiency of laboratory work. QuEChERS ceramic homogenizers provided by Hawach reduces the required extraction time from 60 seconds to 20 seconds, saving nearly 70% of the time per sample, thus greatly improving the working efficiency of the whole experiment. At the same time, it greatly maintains the high recovery and reproducibility of the extraction.

QuEChERS Extraction Salts And Ceramic Homogenizers

The Different Between Extraction Thimbles And Filter Bag

HAWACH extraction thimbles are known for their purity and consistent high quality. We provide a variety of high performing extraction thimbles in various dimensions as well as wall thicknesses. HAWACH offers an extensive range of sizes. The all-in-one design provides excellent mechanical strength and stiffness to ensure that the sample is retained in the thimble throughout the extraction process.

Soxhlet extractors provide a safe method of extraction using toxic or other toxic solvents. It is recommended to use HAWACH extraction thimbles to estimate fats in foods, to analyze paints and adhesives in paints, to extract vitamin A and carotene, and to extract organic compounds from reactive mixtures, which has been found to be satisfactory in applications requiring single or double wall thickness.

Classification
There are two kinds of extraction thimbles at HAWACH, based on the material, cellulose, and glass microfiber thimbles. The cellulose extraction thimble is made of high-quality cellulose cotton fleece with excellent mechanical strength and retention. These thimbles are used in Soxhlet extraction units providing a safe, convenient and efficient method of solvent extraction of solids and semi-solids. Soxhlet extraction is a technique widely used to analyze fats or pesticides in food and soil materials.

The borosilicate glass fiber extraction thimbles are produced for special applications, which can be used at temperatures up to 600°C or with solvents that are not compatible with the cellulose thimble. Its applications include a gravimetric method for high temperature environment, gravimetric method for acidic gas and extraction method commonly used for biochemical analysis, etc.

Applications
Soxhlet extraction
Air and exhaust analysis
Collection of dust and other solid particles
Chimney gas monitoring
Pesticide residue analysis
Grease content of solid food
Grease analysis of solid waste
Biochemical analysis of elution

The design wind speed of the extraction thimbles is a more critical parameter, which is related to the operation of the entire dust collector. In general, we recommend that the design wind speed of filter paper containing wood pulp fibers should not exceed 0.6 m / min. Polyester non-woven fabrics are recommended. The design wind speed is 1 m / min. Of course, we have to consider it more specifically according to the characteristics of the filtered dust.
To solve different types of dust, there are gas turbine extraction thimbles, industrial powdered media filter cartridges, special extraction thimbles for sand suction machines, flame-resistant extraction thimbles, oval extraction thimbles, and slender type instead of bag extraction thimbles.

Compared with filter bag type
1. The filtering area is increased by 3-5 times, and the filtering wind speed is greatly reduced.
2. The dust removal rate is increased by 99.99%.
3. The length of the Extraction Thimbles is short, and there is a large excess space, which is conducive to dust settling.
4. Extraction Thimbles life is extended.
5. Venturi tubes and cages are all exempted.
6. Short and few filter elements, easy to install (top loading), easy to repair and replace

The Different Between Extraction Thimbles And Filter Bag

Standard Operating Procedure Of Bottle-Top Dispenser

Still looking for a measuring unit that is simple to use, comfortable to operate and more importantly offering consistently reliable measuring results? Here is the answer HAWACH bottle-top dispenser.

About HAWACH
HAWACH was registered in the US, Germany, and China. The company’s main laboratory consumables products help clients in biopharmaceuticals, life sciences, industry, education, government agencies and health industries to achieve success. HAWACH’s products are exported to more than 70 countries, such as the United States, Britain, Germany, Japan, South Korea, Singapore, Mexico, Israel and other countries. Its bottle-top dispenser enjoys wide popularity on the market, as it realizes simple and rapid dispensing with sure results. The high quality exhibits the highest degree of chemical and thermal resistance.

Features of HAWACH Bottle-Top Dispenser
The features are as follows:
1.The piston is manufactured from extremely hard, maximum-purity aluminium oxide ceramic. It can inserted in to the glass cylinder with micrometer accuracy, forming a complete seal.
2.It pays attention to every single detail. It is supported by the ergonomically designed handle,making safe and fatigue-free working experience possible.
3.Thanks to the adjustment device, operators can get rapid, consistent, and totally reliable desired volume.

Tips in Operation
In general, no sterilization treatment is required unless special conditions such as abnormal contamination of the sterile liquid or the liquid or the liquid are to be dispensed. ETFE/ FEP/ PFA/ PTEE liquids, such as dissolved sodium azide, are prohibited from sub-packaging. The liquid, such as hydrochloric acid, is prohibited from being sub-packaged to attack the photochemical glass. It is forbidden to sub-package hydrochloric acid, nitric acid and liquid which can form sediment. After the dispenser is in use, keep the piston in position at the lower end. The temperature of the dispenser and the reagent is between 15 and 40 degrees Celsius.

Standard Operating Procedure Of Bottle-Top Dispenser

Instructions For Use Of Syringe Filters

Many of the performance of detection and analysis instruments are exceptionally sensitive, can determine nanograms of substances detection analyzer even in many laboratories has become a standard testing experimental instrument, syringe filter in the drinking water trace detection and analysis of the role can not be ignored, so how to achieve?

The micro syringe filter is a disposable filter device with a microporous filter membrane between two filter Chambers made of high purity thermoplastics without binder. In the detection and analysis of drinking water metal elements, the microporous membrane can be made of several different materials, such as polyester fiber, cellulose acetate and regenerated cellulose.

The current national standard recommends that the diameter of the pore for filtering insoluble solids is 0.45 micron.In addition to PES polyester fiber with aperture of 0.45 micron and CA regenerated cellulose material filter membrane, RC cellulose acetate filter membrane with aperture of 0.2 micron was also used in the experiment.The filter material can be either polypropylene or acrylic acid copolymer mixture.During the production of the injection-type filter, all parts are automatically inspected in accordance with the standard and the welding quality, pressure resistance and flow performance are finally tested by the quality assurance department.

Why the filter distinction?

1. Subarachnoid injection has high requirements, while epidural injection has lower requirements;

2. The adsorption capacity of fine particles in the liquid on the filter paper is poor, mainly by blocking to filter;In addition to the particles in the air being blocked, the ability to absorb filter paper is also higher.Thus, although the filtration capacity of the filter varies, the filtered liquid and gas may be equally clean.

Why do you have to use a liquid filter?

Because when opening ampoules, the liquid medicine is generally contaminated by glass debris.There's video on the web, and it's very clear with high-speed cameras.

How to use filters correctly?

Liquid filter must be one-way use! Syringe has suction, injection 2 kinds of operation, the filter also has suction filtering, syringe filtering 2 kinds of usage.The filter paper of the filter has two surfaces: suction filter surface and syringe filter surface.If suction is also used, injection is also used, the filter loses its effect.

1. Waist hemp with a blue liquid filter, when the drug is used, when the injection to remove, so easy to use.Because the filter has screw mouth, and lumbar hemp needle connection is not convenient;

2. The epidural with a yellow air filter, inhalation or gas injection can be used, clean the environment without also can.Now that epidural gas injection is not advocated, the filter should be in the near future;

3. The epidural catheter should be connected with a filter, and a blue liquid filter should be used.Unfortunately, the only liquid filter in the lumbago combined anaesthesia bag has been used in the lumbago anesthesia (used when inhaling the drug), can not be used again. A yellow air filter is better than none.I wish I had a liquid filter in the anesthetic bag.

Is the filter one-way? Isn't. Why does it sometimes feel like it's one-way? It's just an illusion.

There are several phenomena:

1. If the suction air, no matter inhaling or injection, the resistance is the same;

2. If only the liquid is pumped, the resistance remains the same whether the drug is inhaled or injected;

3. If the air is sucked after the absorption of the liquid, the resistance will be large first and then small when the air passes through the filter paper;

4. If the liquid is inhaled again, the resistance will become great when the liquid reaches the filter paper (it seems that the filter is one-way at this time), and the resistance will return to the normal size after the liquid passes through the filter paper.

Why is there a one-way phenomenon? This is because there are a lot of tiny bubbles in the filter paper, causing the gas plug to block the filter. After the gas plug is removed, the filter returns to normal.

Instructions For Use Of Syringe Filters

How To Buy Sample Vial?

Sample vials are widely used in the lab. It is a special appliance qualified for cleaning according to the international standard: ISO3722 “Identification of Cleaning Methods for Hydraulic Transmission and Sampling Containers”. It’s different from other liquid samplers, just a drink bottle can be used. When cleaning the container by yourself, you don’t know the bottom pollution level (clean RCL value) of the container cavity, and the credibility of the final test result will be questioned.

The special sample vial for particle counter is made by a complete set of processes such as high-precision ultrasonic cleaning machine cleaning, thousands of clean air showers, drying and sealing. The sample vial cleanliness: NAS1638-1 level, which is the particle counter for liquid pollution. Dedicated sampling container for testing. Particle counter special sample bottle is suitable for sample collection of various liquid particle size tests, containing high-clean reagents, containing particulate standard materials and standard samples.

Importance of sample vial quality
If the tolerance is not strictly controlled, the marked size and wall weight of the sample vial of the autosampler may be different, which will affect the sample volume in the sample vial. Hawach is very important for a small number of samples. The strict tolerance control is throughout the whole manufacturing process. From the initial design to the final photoelectric scanning inspection process, it is necessary to ensure the accuracy of the specifications of each sample bottle and bottle cap.

The integrity, cleanliness and homogeneity of sample vial are very important for today’s demanding applications.

How to buy sample vial?
1.Type of sample vial
Sample vial include: clamp cover sample bottle, screw cover sample bottle and bayonet cover sample bottle. The bottle with jaw cover is cheap, but it needs to be equipped with jaw tools, and the cap can not be reused; the sample bottle with screw cover can be reused and is not volatile.

2.Selection of sample vial
Glass – general purpose and acid resistant; brown bottle – for light sensitive samples; silylation / deactivation – for samples that are easy to adhere to the glass bottle wall and trace analysis; polypropylene – for alcohol samples or water-soluble solvents; micro liner – for very little sample size; high yield – for limited sample size.

How to choose a sample vial pad?
1. Red rubber / Teflon vial pad: suitable for routine analysis; moderate tightness and chemical inertness for reuse; most economical.
2. Teflon vial pad: suitable for single injection: poor sealing for repeated use; suitable for MS and ECD analysis.
3. Silicone rubber / Teflon bottle pad: excellent resealing performance; not easy to fall off debris; especially suitable for multiple injection.
4. Teflon / silicone rubber / Teflon bottle pad: for trace analysis application; good resealing performance; the most difficult to fall off debris; the least evaporation.
5. Viton material vial pad: applicable to chlorinated reagents and organic acids; limited resealing.

Sample vial can be used in different area. You can choose according to your application. if have any request, Hawach will provide you best service for you.

How To Buy Sample Vial?

The Function And Installation Of Neutral Alumina

Flash column> is usually used for the chromatography experiment to separate the complicated compounds by pressurizing air. This not only helps provide separation result, but also cuts down on the amount of time required to run column.

The hot air enters the stirring, crushing and drying chamber from the bottom of the dryer at a suitable spraying speed from the inlet pipe, which produces strong shearing, blowing, and rotating effects on the material, so the material is micronized by centrifugation, shearing, collision, and friction.

Strengthened mass and heat transfer. At the bottom of the dryer, larger and wet granules are mechanically broken under the action of the agitator, and particles with lower moisture content and smaller granularity are entrained by the rotating airflow to rise, and are further dried during the ascent. Because the two phases of gas and solid are rotating, the inertia of the solid phase is greater than that of the gas phase, the relative speed between the two phases of solid and gas is relatively large, and the mass and heat transfer between the two phases is enhanced, so the machine has high production intensity.

Hawach flash column will provide you different types of flash column. If you have any question for our product. Don’t hesitate to contact us.

Advantages of HAWACH Flash Column
1.Impurity dissolution rate: the materials are all medical-grade PP and PE, which have strong corrosion resistance and low impurity content. There is low probability of impurity dissolution.
2.Diversity of options: a large number of series/types, imported/domestic adsorbents. The features of diverse specifications is convenient for price-sensitive customers and quality-sensitive customers. Customers in different fields can have multiple choice.
3.Particle size distribution curve of adsorbent silica gel: for the parameters of adsorbent particle size of 3um and 5um, it does not mean that the diameter of all particles is this value, but a range. The result obtained by testing this range is the particle size distribution curve.
4.Report of silica gel partial adsorbent purity test; stability test report for StarFlash standard silica flash column.

Function of Neutral Alumina Flash Columns
Hawach neutral alumina flash columns can be used to extract aromatic amines, highly active porous alumina, whose surface electrons can form pi-pi interactions with aromatic rings with strong polarity retention and acid properties. Compared with unbonded silica gel, neutral alumina flash columns is more stable in a high pH environment and suitable for the extraction of aromatic amines.

Installation of Neutral Alumina Flash Columns
Hawach offers some guidance in properly installation of neutral alumina flash column. The first is to wash the column clean to prevent the adsorption of the pipe wall, if the use of dry loading column can wait for the post after drying the direct loading column, so that the filler precipitation is uniform, to elute, so that the column bed to maintain balance, and then can be sampled. If the column is wet, first use the eluent saturated filler, and then press the black button to press the neutral alumina column down. The whole process should be very slow, the sample drop by drop into the column, too fast adsorption, desorption effect is not ideal.

The Function And Installation Of Neutral Alumina