RU120227U1 - MULTI-TOUCH SYSTEM FOR DETERMINING VOLATILE COMPONENTS IN AIR FOR THE PRODUCTION OF BUILDING MATERIALS FROM POLYMER COMPOSITES - Google Patents

Abstract

The multisensor system for the determination of volatile components in the air during the production of building materials from polymer composites contains a sensitive element, which is a piezoelectric crystal transducer made in the form of a piezoelectric quartz base having a temperature-sensitive AT cut, on both sides of which there are electrically conductive plates connected to a natural vibration frequency meter, characterized in that a catalyst is applied to the thermosensitive cut of the piezoquartz base, acting with the analyzed combustible gas with the release of heat, and the catalyst or the analyzed gas is heated to the temperature of the oxidation reaction of the combustible gas on the catalyst, and an additional electrically conductive strip connected to the source is applied to the piezoelectric base current, and the sensor is equipped with a second piezo-crystalline base with electrically conductive plates connected to the frequency meter, and electrically conductive strips connected to the source of t eye, but in which the catalyst was removed from the thermosensitive cut.

Description

A well-known universal multisensor detection cell with a volume of 200 cm ³ with injection injection of a sample of the analyte with a volume of 10 μl with a microsyringe directly into the cell [Selectivepiezoelectricodorsensorusingmolecularlyimprintedpolymers.Ji HS., McNiven S., Ikebukuro K., KarubeI. // Anal. Chim. Acta. 1999. V.300. P.93-100]. The sensor before measurements is kept in a stream of nitrogen at a flow rate of 0.2 DM ³ / min until the analytical signal is stabilized. Then, the nitrogen supply is stopped, and 10 μl of the solution of the analyte is introduced into the cell and evaporated. Measurement of the analytical signal is stopped when the change in the frequency of the oscillations of the sensor does not exceed 1 Hz / min

The closest in technical essence and the achieved effect is a detection cell with a volume of 500 cm ³ made of stainless steel, equipped with a thermostatic jacket, the outer side of which is covered with heat-insulating material, consisting of a reaction vessel, inlet pipes, air and sample outlets, a piezoelectric crystal, and the lid with an integrated holder for the piezoelectric crystal made of the same material, and the nozzle for direct injection of the sample into the reaction vessel of the cell is equipped with silicone gasket (Patent 2207539, G01N 5/02, 27/12. Declared 06/20/2002).

The disadvantages of this cell are the inability to determine several volatile substances that make up the analyzed object, because there is only one piezoelectric crystal sensor, the duration of equilibrium due to the presence of a concentration gradient, the inability to determine the partial pressures of substances.

The objective of the invention is the creation of a universal multi-sensor detection system that allows you to identify gaseous products released during the production of building materials from various polymer composites, to obtain an accurate quantitative assessment of the interaction of several analytes (up to 10) with selective sorbents deposited on the electrodes of a piezoelectric crystal, to eliminate the concentration gradient inside the cell, increase the volatility of the determined components.

This problem is achieved due to the fact that a catalyst is applied to a heat-sensitive section of the piezoelectric crystal, which acts with the combustible gas to be analyzed to generate heat, and the catalyst or the analyzed gas is heated to the temperature of the oxidation reaction of the combustible gas on the catalyst.

The technical result provided by the given set of features is the ability to:

analyze gaseous products released during the production of polymer-based building materials;

- timely detection of fire and explosive conditions, with subsequent measures to eliminate the causes of an emergency.

Universal multi-sensor system for determining volatile components in the air in the production of building materials from polymer composites (Figure 1) consists of two cylindrical parts 1, 2, tightly interconnected through a perforated metal plate 3 for continuous analysis of volatile components of the air and fluoroplastic plate 4 to transfer our system from continuous to periodic, equipped with a jacket for temperature control 5 with nozzles for input 6, air outlet (gas-air with esi alloy volatiles) 7, a bleed nozzle 8 for pressure relief and regeneration sensors removable holder 9 to 10 pezosensorov 10 connected to the electronic control unit 12.

Figure 1

Universal multi-sensor system for determining volatile components in the air in the production of building materials from polymer composites works as follows. A pre-prepared holder with an appropriate set of piezoelectric quartz sensors is placed in the upper part of the cell, which is preliminarily held in the flow of dried laboratory air for several minutes until a stable analytical signal is obtained, and the sensor readings are measured (for each type of the analyzed sample, its own set of sorbents applied to the sensor is selected). Then, through the inlet and outlet nozzles by means of a compressor, the studied air is continuously pumped with a simultaneous analysis of its piezoelectric sensors. The stopwatch counts the time after which the signal of the piezoelectric sensors does not change. The difference between the signals of the piezosensors before and after contact with the carrier gas enriched with the components of the sample is a characteristic of qualitative and quantitative determinations. The detachable parts of the cell make it easy to service (prepare for a new analysis). After the analysis is completed, a removable holder with sensors is removed, the cell is washed and dried to remove residual volatile compounds, a new sensor holder with an appropriate set of sorbents is inserted. After that, the cell is ready for analysis again.

Claims (1)

The multisensor system for determining volatile components in the air during the production of building materials from polymer composites contains a sensitive element, which is a piezocrystalline transducer made in the form of a piezoelectric quartz having a heat-sensitive AT-cut, on both sides of which are electrically conductive plates connected to a natural frequency meter, characterized in that a catalyst is applied to the heat-sensitive section of the piezoelectric crystal base, acting with analysis combustible combustible gas with heat generation, and the catalyst or the analyzed gas is heated to the temperature of the oxidation reaction of the combustible gas on the catalyst, as well as on the piezoelectric quartz base, an additional electrically conductive strip is applied connected to the current source, and the sensor is equipped with a second piezocrystalline base with electrically conductive plates connected to a frequency meter, and electrically conductive strips connected to a current source, but in which the catalyst is removed from the heat-sensitive cut.