Device and method for measuring vacuum degrees in hollow glass microbeads

Abstract

The invention relates to a device and method for measuring vacuum degrees in hollow glass microbeads. The device comprises a measuring cavity, hollow glass microbeads, a container, an extrusion piston, a hydraulic motor, a thermocouple, an absolute pressure meter, a precision piston, a differential pressure meter, a balance valve, a reference cavity and the like. Since the vacuum glass microbeadsare stacked in a powder manner and the powder stack not only contains gas in the hollow glass microbeads but also contains stacking gaps between the hollow glass microbeads, the measurement of the vacuum degrees in hollow glass microbeads is realized by two steps: firstly, testing the porosity of the stacked powder; and secondly, testing the internal pressures of the hollow glass microbeads. According to the invention, a large number of stacked hollow glass microbeads are broken; and difficulties of high measurement difficulty and low measurement precision of a single micro-nano vacuum container are eliminated by measuring the pressure change in the whole cavity.

Description

technical field [0001] The invention belongs to the field of devices for measuring vacuum degree, in particular to the field of measuring vacuum degree in hollow glass microspheres. Background technique [0002] Hollow glass microspheres are small hollow glass spheres with a size of about 15-150 microns and a wall thickness of 0.5-2 microns. They have light weight, low thermal conductivity, sound insulation, high dispersion, electrical insulation and good thermal stability. Advantages, when the interior of the hollow glass bead is vacuum, it has good thermal insulation performance, and is an excellent thermal insulation material; the hollow glass bead is a rigid hollow microsphere with good sphericity, and the particles are in point contact. The structure makes the heat conduction path longer, which can effectively reduce the contact heat conduction; the hollow glass microsphere is a closed-pore microsphere, which seals the gas inside the sphere, and prevents the gas flow an...

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Problems solved by technology

The composition of hollow glass microspheres is similar to that of glass, which not only has the characteristics of non-combustibility and flame retardancy, but also has a wide range of operating temperatures (temperatures below 600°C are acceptable); in addition, hollow glass microspheres also have low vacuum requirements ( In the vacuum range of 0.01-10Pa, it shows good thermal insulation performance. The lower the vacuum degree in this range, the better the thermal insulation performance. You can choose the appropriate vacuum degree according to the thermal insulation requirements and the airtightness of the heat preservation container), and the vacuum holding capacity Well, it has a series of advantages such as low maintenance frequency and simplicity in the later stage, and has great potential application value; in recent years, it has also become one of the important materials in the fields of oil drilling, deep sea exploration, aerospace, heat insulation, etc. The important characterization indicators of beads mainly include: compressive strength, true density, floating rate, packing coefficient and particle size, etc., but the existing density measurement is not accurate, there is no good measurement method, and there is no effective realization of micro-nano Apparatus and method for measuring vacuum degree in vacuum container

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