Water Precipitation Tank

The principle of a water precipitation tank is consistent with that of an alcohol precipitation tank, and it is a commonly used process step in the traditional Chinese medicine extraction process. The water precipitation tank corresponds to the alcohol precipitation tank. After the concentrated liquid of the alcohol extract of traditional Chinese medicine is concentrated, water is added at normal or low temperature for water precipitation. Water acts as both a solvent to dissolve the effective components in the concentrated liquid and a precipitating agent to precipitate some impurities in the alcohol extract. Water precipitation is a method of removing impurities from the extraction liquid by means of water precipitation. It removes impurities, reduces the dosage, and has the characteristics of refinement and convenience for preparation, enabling the traditional Chinese medicine extracts to be made into Chinese patent medicines.

The water precipitation tank is used in the alcohol – water extract or concentrated liquid of the traditional Chinese medicine to be prepared. After adding 1 – 4 times of water, it is left to stand for sedimentation to remove water – insoluble substances in the solution. After recovering and removing ethanol, water is added again to dilute to a specified concentration, and then it is filtered and filled for sterilization. Its basic principle is to utilize the property that the effective components of traditional Chinese medicine are soluble in both ethanol and water to achieve refined products and improve the quality of the prepared products.

The principle of water precipitation is to use ethanol with a certain concentration prepared from the alcohol liquid. When reaching the concentration for removing impurities, generally, when the ethanol concentration reaches 50% – 60%, proteins and starches can be removed; when the ethanol concentration reaches 75%, impurities such as proteins, polysaccharides, and inorganic salts can be removed. Thus, effective components such as alkaloids, glycosides, amino acids, and organic acids that are soluble in both water and alcohol are retained. Therefore, for those extracted with water, alcohol precipitation is used for sedimentation, and for alcohol extracts, water precipitation is used for sedimentation. Hence, the structure and principle of the alcohol precipitation tank and the water precipitation tank are the same.

A water precipitation tank is welded from three layers of stainless steel. The inner tank is made of high – quality stainless steel SUS316L/304, and the inner tank is polished, meeting the requirements of food and pharmaceutical hygiene levels. The interlayer is made of SUS304 stainless steel, and a stainless steel deflector is set in the interlayer, which is conducive to the diversion of cooling water. The outer welding is filled with a stainless steel outer package, and polyurethane insulation is set, which is conducive to heat preservation, preventing heat from dissipating quickly, and is environmentally friendly and energy – saving.

The water precipitation tank has cooling, heat preservation, and stirring functions. The tank body is designed with process nozzles such as a material inlet, a pure water port, a discharge port, a sampling port, and heat exchange inlets and outlets. The water precipitation tank is designed with an automatic control system, including process controls such as feeding, discharging, temperature control, and stirring, which reduces labor intensity and enables the precipitation process to realize fully automatic control.

A clear liquid outlet is set, and the liquid output can be adjusted according to the liquid level height. A guide gear is installed on the upper clear liquid outlet pipe. Through the liquid outlet pipe outside the tank top, the liquid forms a certain angle with the cylinder body, and the liquid outlet pipe can rotate 360°, so that the precipitate (including flocculent substances) is not sucked out. The handwheel on the tank top adjusts the rotation direction of the liquid outlet pipe to ensure that the upper clear liquid is basically pumped out without affecting the precipitation and discharge. A long sight glass is set on the tank wall to facilitate observation of precipitation and the separation interface of the upper clear liquid and the sediment, so as to observe the sedimentation and separation of the material liquid in the tank. For a good separation effect, the bottom of the water precipitation tank is generally conical, with a cone angle of 90° – 120°.