A General Introduction Of Bottle-Top Dispenser
Hawach bottle-top dispenser is fixed to the reagent bottle by a screw valve and is closed tightly and firmly so that the process of removing the solution is in a closed system, which avoids the evaporation, splashing, and tipping of the solution, so as to reduce the impact on the environment and people. Compared to the fully open process, it is much safer.
High-viscosity, high-density, high-volatile solvents are not uncommon in organic synthesis or petrochemical laboratories, especially in the petrochemical industry. Due to their special properties, such solutions are difficult to remove quickly, and it is difficult to accurately quantify with traditional measuring cylinders. Bottle-top dispensers are perfectly capable of handling such solutions.
As they are easy, fast and convenient to remove reagent, bottle-top dispensers are widely used in laboratories, replacing the operation of pouring into graduated cylinders. They can be mounted on commercial reagent bottles directly or via adapters. It is no longer necessary to dispense or mobilize chemicals in advance, which is especially convenient for continuous reagent removal.
Functional principle of the bottle-top dispenser
By moving the piston upward, a preset amount of liquid is drawn into the piston chamber of the dispenser from the reagent bottle. By moving the piston down, the liquid is discharged through a valve system and a drain pipe. There is no longer to set meniscus and follow latency.
Bottle-top dispensers are generally divided into two types: “float” pistons and “friction seal” pistons. Bottle-top dispensers using a “float” piston, which does not require a piston seal, so it is very durable and easy to maintain. The piston is placed in the cavity of the dispensing piston without contact. A gap of one-thousandth of a millimeter wide between the piston and the piston cavity is filled with the removed liquid. This liquid film acts as a lubricant, making the movement of the piston very smooth. In addition to the “float piston” operating principle, the “friction seal” piston principle is used for bottle-top dispensers. These systems often require higher operating forces and frictional losses in the piston can cause seal failure.
Its applications include daily removal of low concentrations of bases, acids, biological buffers, cell culture media, biological surfactants, and polar solvents. Some are suitable for removing acids (such as concentrated hydrochloric acid), polar solvents (such as acetone), essential oils, and UV-sensitive reagents.
To be more specific, it can be summarized as follows:
1. Remove corrosive reagents, including concentrated acids such as H3PO4, H2SO4, alkalis such as NaOH, KOH, salt solutions, and many organic solvents.
2. Remove organic reagents, including chlorinated hydrocarbons or fluorinated hydrocarbons (for example, trichlorotrifluoroethane, dichloromethane, etc.), high-concentration acids (For example, hydrochloric acid (HCl), HNO3, etc.), TFA, tetrahydrofuran (THF), peroxides, and the like.
3. Remove hydrofluoric acid
According to different application requirements, the parts in contact with liquid are made of various special resistant materials, such as ceramic, platinum-iridium, tantalum, ETFE, PFA. When choosing a bottle-top dispenser, the safety characteristics of the instrument must be kept in mind. For example, can it reduce the risk of injury that could result from glass breakage? How to prevent accidental splashing of liquid-filled instruments? How to reduce the possibility of contact with the reagent when the drainpipe is closed?
Similarly, the user should confirm the compatibility of the removed liquid with the bottle-top dispenser. Relevant information can usually be found in the “Using functions and restrictions” section of the operating manual. Information on maintenance and measuring instruments can also be found in the operating manual.
According to ISO and GLP guidelines, the accuracy of the bottle-top dispenser should be checked regularly and calibrated when necessary.