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Weighing Instruments Application Is Very Extensive
May 26, 2017

Weighing Instruments in the pharmaceutical industry in a wide range of applications, such as materials out of storage, production and packaging of raw materials, pharmaceutical preparation, testing, preparation of pharmaceutical production and packaging. In order to reduce the possibility of product cross-contamination and microbial contamination, all equipment related to drug production must meet GMP. Weighing Instruments is one of the key points in the quality and health and safety control of pharmaceutical production. Throughout the pharmaceutical production process, Heavy accuracy is very important, Weighing Instruments or a potential source of pollution, must always be clean, there can be no clean dead ends. The surface roughness of the stainless steel and the degree of protection of the equipment itself must also be taken into account in the clean production area to prevent microbial aggregation and ease of cleaning.

Pharmaceutical companies in the purchase of electronic weighing to carefully consider the following questions: Do you want to weigh corrosive substances? Is it used to weigh explosive substances? Weighing wet or dusty conditions (degree of protection)? What is the purpose of purchasing electronic weighing (weighing, checkweighing, counting, filling, recipe application)? Do you want to print? Need to and computer networking easy to control? Do you want to have the minimum weighing warning function? Also need to provide electronic scales which applications?

In the production of raw materials, the traditional sense, for the distribution tank and storage tank is the use of flow meter and liquid (material) bit of the way. In terms of volume measurement, some media are less accurate in terms of constant volume (eg, 100 mL of water is added to 100 mL of 95% alcohol, <200 mL, and the mass is constant), and the flowmeter and Liquid (material) are required to direct contact with the material, not in line with GMP. With the progress of the weighing technology and improve, non-contact, not affected by the characteristics of materials, can adapt to different processes and materials, more in line with GMP weighing detection methods are increasingly applied, such as bio-engineering and API Preparation and so on.

This paper focuses on the application of Weighing Instruments in the formulation of injectable preparations. At present, some high-end pharmaceutical companies began to use the weighing technology to inject the preparation process to control and testing to improve the level of measurement management automation to ensure the quality of drugs. In the case of a typical dispensing system in the production of injections, as shown in Figure 1, the three pressure weighing modules installed at the bottom of the tank convey the weight signal of the tank to the junction box, The weighing module signal is adjusted and the angle difference is adjusted according to the load condition of each weighing module. After the collected weighing signal is sent to the weighing terminal or the weight transmitter, the weighing terminal or the weight transmitter will process the weight signal Into the corresponding weight data, upload to the PLC or DCS system, to achieve weighing and batching control to ensure product quality.

1 Weighing module selection

1.1 Weighing module dynamic or static load selection

Toledo-Mettler's weighing modules are divided into static and dynamic loads. The feeding method determines the type of weighing module. When the material is fed vertically in the conveyor or pump to the bucket, tank, kettle and tank, the static load module can be used. When the material is transported to the weighing platform horizontally or When the container or tank with a stir, it will produce a horizontal impact force, this time should use the dynamic load module.

1.2 Quantity selection

Cylindrical containers are generally 3-point support, 3 modules for a group (fixed, semi-floating and floating 1), rectangular containers are 4 points to support is appropriate, 4 modules for a group (fixed and half Floating 1, floating 2), special circumstances, in order to improve the container stiffness, can increase the support point. In the four module configuration based on the increase in the module, all selected floating structure.

1.4 Weighing module material and selection

METTLER TOLEDO offers two types of weighing modules. FW static load modules are made of carbon steel in addition to pressure heads. For general applications, CWC, FWC, UW, GW stainless steel weighing modules are available for Corrosive substances and wet contact and other occasions. The CWC stainless steel weighing module is generally selected on the mix with a stirred solution.

1.5 Select the appropriate weighing instrument, junction box and cable

Weighing instrument models are different, the display speed and accuracy will be different, pay attention to select and weighing module to adapt to the appropriate weighing instruments, junction boxes and cables.