The hottest water-soluble film coating II

Water soluble film coating (II)

* height from the spray gun to the tablet bed

the tablet bed may also be different according to the load of the coating pot, the batch output, and the size and shape of the tablets. The spray gun should be placed at the upper third of the tablet bed and the bottom of the guide cylinder. In each coating process 3, output situation: ① written report; ② The position of the spray gun should be rechecked before the start of the curve or after the load of the coating pot changes

* calibration

it is also very critical to calibrate the spray gun. It is a common problem that there is a deviation in the spray rate of solution between different spray guns. However, the deviation between spray guns should not be greater than ± 10 ml. If the deviation exceeds the recommended value, it can be adjusted through the needle valve on the back of the spray gun

the words on the coated tablets in the figure are worn

atomization and setting air

the degree of atomization and setting air must be carefully set. Too much shaping air will flatten the cone, resulting in overspray, timely elimination of excessive humidity and "sticking" and other problems. Too little shaping air will make the cone concentrate in a very small area on the tablet bed, resulting in the wear of the tablet center or "sticking"

shaped air determines the shape of the suspension cone, so the more air, the flatter the cone. In some systems, the setting air is fixed, while in other systems, it is variable and set by the operator

coating pot pressure

the compact structure and reasonable layout of the pressure machine often lead to product defects, but this is often wrongly attributed to other reasons. This pressure value can never be positive. Generally, it should be between -0.1 and -0.5in (H2O). It should never exceed -1.0 in H2O。 When the gasket used to maintain the pressure is aged or broken, the pressure of the coating pot may decrease sharply. Therefore, any faulty gasket should be replaced immediately

coating pot speed

there is no single standard for the speed setting of the coating pot, although there are some empirical rules based on factors such as tablet size, shape and load. For each product, two basic speeds should be set: the initial speed to obtain the basic coating effect, and then a constant speed to obtain the best tablet appearance

anti slip strips and diaphragms can also be placed in the center of the tablet bed and in front of the air outlet. They are not used for mixing. They should be installed in any case, and Japanese experts will also exchange and share on a regular basis. However, diaphragms do have a certain mixing effect, and are usually provided as a standard accessory, no matter which manufacturer will do so

liquid spraying speed

the liquid spraying speed of each spray gun should usually be set between 80~150 ml/min. If the distance between the spray gun and the tablet bed is 8 inches, it is recommended to set the spraying speed of each spray gun to 80 ml/min. If the distance between the spray gun and the tablet bed is 10 inches, the recommended spray rate is 120 ml/min

inlet and outlet temperature

the operator should set the outlet temperature at the target value, generally between 45~55 ℃, and let the inlet temperature change within a specific range. The key point is to remember that the inlet air temperature is a set point, and the outlet air temperature is a function. Its calculation method is as follows: inlet air (unit: foot 3/minute or CFM) + T inlet air + liquid injection speed + atomized air = t outlet air

therefore, monitoring the outlet air temperature helps to determine whether other parameters have changed