Explosion proof design cannot be ignored in pharmaceutical wet granulation

When it comes to the development of the pharmaceutical industry, we naturally associate it with the upstream pharmaceutical industry - pharmaceutical equipment, among which the wet granulation machine is one of the key equipment in the pharmaceutical production process.

The preparation process of almost all solid preparations cannot be separated from the granulation process. The particles produced may be the final product, such as granules, or the intermediate product, such as tablets. Wet process particles, after surface wetting, have the advantages of good particle quality, beautiful appearance, strong abrasion resistance, and good compression molding, and are widely used in the pharmaceutical industry.   

Wet granulation machine is of great significance in the pharmaceutical production process, but explosion-proof factors should be fully considered in the design process. According to relevant technical personnel, the wet granulation machine generates static electricity and electric sparks during the feeding process and the friction of powdered materials in the dry powder mixing process. Once the mixing ratio of air dust mixture reaches the flash concentration and encounters electric sparks, flash explosion will occur.

The solid powder materials used in the pharmaceutical industry, including auxiliary materials such as starch and corn starch, have different explosion hazard levels. Therefore, it is required that the equipment for producing solid preparations of drugs with dry powder materials have explosion-proof and anti explosion functions to ensure the safety of equipment use. The high explosive pressure of starch, a commonly used pharmaceutical excipient in pharmaceutical processes, is 1 MPa. Therefore, the wet granulation machine and fluidized bed design should have an anti explosion capacity of 10-12 bar. The general explosion-proof methods mainly include muffled explosion, explosion-proof, explosion-proof, and explosion suppression. In wet granulation equipment, it is necessary to choose the appropriate explosion-proof method according to the actual product needs of the customer.   

According to relevant technical personnel, muffled explosion refers to the technology of enclosing an explosive mixture that can be ignited inside a device, which can withstand the explosive pressure of the internal explosive mixture and prevent it from spreading to the surrounding area.   

The main criteria for explosion suppression are the structural strength and explosion-proof performance of the equipment. The equipment casing is the object that can withstand explosive force, and therefore it has become a representative of the strength of explosion-proof equipment. The equipment casing is generally composed of several connecting components. The connection between connectors inevitably leaves a gap in the joint. In order to prevent the explosion inside the shell from spreading to the outside, the strength of the equipment shell, the length, gap, and roughness of the joint surface must meet the requirements. The reason why it can have a suffocating effect, in other words, is that the equipment shell covers the explosion through its strength, so that the explosion inside the equipment will not be transmitted to the outside, thereby reducing the losses caused by the explosion.   

In the process of explosion design, it is necessary to fully consider the structural strength and sealing performance. As for the sealing form of airbags between the granulator and fluidized bed, airbags are added to the groove at the connection point. The airbags are in an inflated state during operation, which effectively isolates the inside and outside of the container, preventing pressure, flames, and explosion products from spreading outward in the event of an explosion.   

In addition to the explosion-proof design of the equipment itself, technicians have stated that the wet granulation line is a system, so effective isolation between process units should also be considered to limit the explosion within a certain range and prevent it from spreading between equipment, causing systemic damage.   

The granulation operation gives the particles a certain purpose to ensure product quality and smooth production. In granules and capsules, granules are products, and the purpose of granulation is not only to improve the flowability, dispersibility, adhesion of materials, facilitate accurate measurement, and protect the production environment, but also to ensure that the shape and size of the granules are uniform and aesthetically pleasing. In tablet production, particles are intermediates, and it is not only necessary to improve flowability to reduce weight differences in tablets, but also to ensure the compression formability of particles. Wet granulation technology is a widely used technique, and in order to better apply this technology to pharmaceutical production, explosion-proof technology cannot be ignored.