Abstract The tightness of the mask is an important indicator for evaluating the protective performance of the mask. The better the tightness, the better the fit between the selected mask and the user's face shape. The user can get the expected protective effect by wearing this mask. This article briefly introduces the test method, principle and equipment of the mask tightness test. From the test process described in this article, it is relatively simple to use the GB-MH180 Mask Tightness Tester to test the mask fit performance, and the tester is easy to operate and intelligent. The tester adopts imported embedded particle counter and imported air filter, the test result is highly accurate, which can quickly and accurately verify the tightness of respiratory protective equipment such as masks. The protective effect of the mask depends not only on the filtration efficiency of the filter material, but also on the degree of close contact with the wearer's face. In actual use, it is impossible for the edge of the mask to completely fit the face. Except for a small amount pollutants that penetrates through the filter material, most of the other pollutants leak from the fitting part of the mask and the face. Ordinary users often only pay attention to common issues such as the protection of masks against particulate matter and germs, while ignoring the individuality of whether the mask matches the user. suitable to reduce its protective effect. Therefore, the tightness is an important indicator for evaluating the protective performance of masks. GB 19083-2010 technical requirements for medical protective masks stipulates 'The design of the mask should provide good tightness, and the total fit factor of the mask should not be less than 100'. PART 01 Test methods and instrument Standard US Occupational Safety and Health Administration (OSHA) standard "Respiratory Protection" (29 CFR1910.134) GB 19083-2010 Technical requirements for medical protective masks; GB/T 18664-2002 Selection, use and maintenance of respiratory protective equipment; OSHA 29 CFR1910.134 Respiratory Protection.   The tightness of respiratory protective item such as masks is determined by a fit test. Suitability tests are divided into qualitative suitability tests and quantitative suitability tests. Qualitative suitability tests are based on the subject's perception of the test agent (saccharin, irritating smoke, etc.) to judge the results. Due to the subjectivity of its judgment, it is easy to lead to the failure of the test results. The quantitative fit test requires the aid of a mask tightness tester. The test principle of the quantitative suitability test: by using the mask tightness tester to quantitatively measure the concentration of the external testing agent of the respiratory protective equipment and the concentration of the testing agent leaking into the respiratory protective equipment during the simulated operation activities of the person wearing ...

ABSTRACT: The residue-on-evaporation method of purified water is to detect the quality of residue on evaporation solids obtained after 100 mL of purified water is evaporated and dried. The difficulty is that the operator needs to repeat the operation to achieve the 0.3mg constant weight value required by the Chinese Pharmacopoeia. The traditional test method has the shortcomings of low efficiency and manual duty. After long-term practice and repeated verification, it adopts an integrated automatic structure design, equipped with rapid water bath evaporation and gas balance technology, which can realize automatic feeding, water bath evaporation, blast drying and cooling balance, constant temperature weighing five-in-one automatic test. Through the repeatability experiment and gradient design experiment, the results show that: 2 rounds of weighing can reach a constant weight error value of 0.3mg, when the scalar amount is 9.4mg/100mL, the precision (RSD) is 0.73%, and the accuracy of the gradient design experiment is high. There is no deviation between parallel samples. Conclusion: After the innovation of the residue on evaporation detection technology of purified water, the test time to reach constant mass value is short, the operation is simple, and the data accuracy and precision are good. KEYWORDS: purified water; residue on evaporation; constantmass; automated test 01 Standard requirements According to the requirements of Chinese Pharmacopoeia 2020 Edition Part II "Purified Water": Take 100mL of this product, put it in an evaporating dish with constant weight at 105°C, evaporate it to dryness on a water bath, and dry it at 105°C to constant weight, and the remaining residue should not exceed 1mg. The Chinese Pharmacopoeia defines constant weight as constant weight, unless otherwise specified, refers to the weight of the test sample after two consecutive drying or igniting weighing the difference is less than 0.3mg; the second drying to constant weight and each subsequent weighing should be carried out after 1 hour of drying under the specified conditions. According to the requirements of European Pharmacopoeia 10.0 Edition, about “Purified water in containers“， Residue on evaporation: maximum 0.001 per cent. Evaporate 100 mL to dryness on a water-bath and dry in an oven at 100-105 °C. The residue weighs a maximum of 1 mg. The requirements of the Chinese Pharmacopoeia, the US Pharmacopoeia and the European Pharmacopoeia for limits of constant mass and residue on evaporation in purified water are shown in Table 1. It is worth noting that the US Pharmacopoeia does not require residue-on-evaporation items for purified water, the European Pharmacopoeia has no residue on evaporation testing items for Purified water in bulk, while Purified water in containers does not. For residue on evaporation testing items, the limit requirement is also ≤10mg/L, but there is no requirement for constant weight....

Summary The non-volatile matter test principle of purified water is to detect the mass of non-volatile matter solids obtained after 100mL of purified water is evaporated and dried. The difficulty is that testers need to perform repeated operations to achieve the 0.3mg constant weight value required by the Chinese Pharmacopoeia. The traditional test method has the disadvantages of low efficiency and manual on-duty. After long-term practice and repeated verification, it adopts an integrated and automated structural design, equipped with rapid water bath evaporation and gas balance technology, which can realize automatic feeding, water bath evaporation, blast drying, and cooling. Balance, constant temperature and weighing five in one fully automatic test. Through repeated experiments and gradient design experiments, the results show that: 2 rounds of weighing can reach a constant weight error of 0.3mg, and when the amount of scalar addition is 9.4mg/100mL, the precision (RSD) is 0.73%, and the accuracy of the gradient design experiment is high. There is no bias between parallel samples. Conclusion: After the innovation of the non-volatile detection technology of purified water, the constant weight time is short, the operation is simple, and the data accuracy and precision are good. Key words: purified water; non-volatile matter; constant weight; automated testing In the production of pharmaceuticals, purified water is widely used as solvents, detergents, auxiliary materials, raw materials for pure steam and water for injection, etc., from raw materials to preparations, the use of purified water runs through the entire production process. Therefore, the quality control of purified water is very important in the production management of pharmaceutical companies. The test of non-volatile matter in purified water is one of the basic inspection items. The difficulty lies in the 0.3mg constant weight value required by the Chinese Pharmacopoeia. Experimental stop condition. Traditional testing methods have disadvantages such as low efficiency, repetitive and cumbersome operations, difficulty in constant weight, and the need for manual supervision. Domestic and foreign standard requirements According to the requirements of "Purified Water" in the second part of the Chinese Pharmacopoeia 2020 edition: take 100mL of this product, put it in an evaporating dish with a constant weight at 105°C, evaporate it to dryness on a water bath, and dry it to a constant weight at 105°C. The remaining residue should not exceed 1mg. The definition of constant weight in the Chinese Pharmacopoeia is constant weight, unless otherwise specified, refers to the weight of the test sample whose weight difference is less than 0.3 mg after two consecutive dryings or igniting; the second time of drying to constant weight And every subsequent weighing should be carried out after continuing to dry for 1 hour under the specified conditions. See Table 1 for the requirements of the Chinese ...

Packaging plastic films refer to films made of polyvinyl chloride, polyethylene, polypropylene, polystyrene and other resins for packaging, as well as for use as a laminating layer. The share of plastic packaging and plastic packaging products in the market is increasing, especially the composite plastic flexible packaging, has been widely used in food, medicine, chemical and other fields, among which the largest proportion of food packaging, such as beverage packaging, frozen food packaging, steamed food packaging, fast food packaging, etc. These products have brought great convenience to people's lives. In order to ensure the effectiveness of packaging products, it is required to have good barrier performance, which is measured by an important indicator is the water vapor transmission rate (amount). There are many testing standards on water vapor transmission rate (amount) at home and abroad, of which the following are the common testing standard methods. ISO 15106-2 - Plastics -- Film and sheeting -- Determination of water vapour transmission rate -- Part 2: Infrared detection sensor method ASTM F1249 - Standard Test Method for Water Vapor Transmission Rate Through Plastic Film and Sheeting Using a Modulated Infrared Sensor TAPPI T557 - Water vapor transmission rate through plastic films and sheeting using a modulated infrared sensor ISO 2528 - Sheet materials -- Determination of water vapour transmission rate -- Gravimetric (dish) method ASTM E96 - Standard Test Methods for Water Vapor Transmission of Materials ASTM D1653 - Standard Test Methods for Water Vapor Transmission of Organic Coating Films TAPPI T464 - Water Vapor Transmission Rate of Paper and Paperboard at High Temperature and Humidity ISO 15106-3 - Plastics -- Film and sheeting -- Determination of water vapour transmission rate -- Part 3: Electrolytic detection sensor method W900 Gravimetric Method Vapor Transmission Rate Tester 1.Analysis from the principle of the test method Visible film water vapor transmission rate (amount) detection methods are mainly divided into two categories, respectively, the gravimetric method and the sensor method. The gravimetric method (also known as cup method) is divided into two types of weight gain method and weight loss method, which detects the weight change of the moisture vapor transmission cup. Electrolysis analysis method and infrared detector method belongs to the sensor method, which, the principle of electrolysis method refers to the electrolysis of water vapor encountered electrodes for hydrogen and oxygen, through the electrolysis current to calculate a certain period of time through the unit area of the sample water vapor transmission rate (amount); infrared method is the principle of water vapor from the high humidity cavity through the sample penetration to the low humidity cavity, the electrical signal generated by the carrier gas transmitted to the infrared detector to calculate the water vapor permeation rate (amount). W203 ...