RU2222776C2 - Device measuring thickness of nonmagnetc materials - Google Patents

Abstract

FIELD: measurement technology, measurement of thickness of plates, sheets, paper, leather, fabrics, plastic masses, nonmagnetic metals. SUBSTANCE: device measuring thickness of nonmagnetic materials has measurement head 9 and container 5. Container 5 housing ball 4 is centered relative to head by moving so that ball 4 appears to be in center of circle which center is located in geometrical center of plate 7. Magnetic dispersion flux F_s from magnet 8 closes through Hall sensor 1, measured material 11 and components 4 and 7. Value F_s depends on thickness of material 11. With change of thickness of measured material value of emf of Hall sensor 1, voltage across output of amplifier 2 and readings of indicator 3 change. EFFECT: increased measurement accuracy of device thanks to provision for more precise centering of ball relative of axis of measurement head. 1 dwg

Description

 The device relates to the field of measurement technology and can be used to measure the thickness of non-magnetic materials, in particular for measuring the thickness of plates, sheets, paper, leather, fabrics, plastics, non-magnetic metals.

 A device for measuring the wall thickness of products made of non-magnetic materials, containing an unbalanced bridge of alternating current, a ferromagnetic body and direct current electromagnets (see ed. St. USSR 750263, class G 01 B 7/06, claimed 18.01.78, published 23.07. 80).

 The known device is unsuitable for measuring the thickness of soft materials due to deformation of the measured material at the point of contact with the ball, has a low measurement accuracy.

 Closest to the claimed is a device for measuring the wall thickness of products made of non-magnetic materials, containing a source of magnetomotive force in the form of a permanent magnet with a tip of magnetostrictive material at the working end, an auxiliary ferromagnetic element, a power supply, a measurement unit with a Hall sensor, a registration unit (see ed. St. USSR 1597521, class G 01 B 7/06, claimed 11.25.88, published 07.10.90) - prototype.

 The disadvantage of the prototype is the limited range of measured values, as well as the low measurement accuracy with increasing thickness of the measured material.

 To eliminate these shortcomings in a device for measuring the thickness of non-ferromagnetic materials, containing a measuring head with a magnet and a Hall sensor placed on it, the signal electrodes of which are connected through an amplifier to the indicator, and current electrodes to the outputs of the power supply, an auxiliary element in the form of a ferromagnetic ball, an auxiliary element placed in a container with a window open for observation, and the bottom of the container is made in the form of a ferromagnetic plate.

 The drawing shows a structural diagram of the inventive device.

 The device contains a Hall sensor 1, the signal outputs of which through an amplifier 2 (inputs U1, U2) are connected to the input of the reading indicator 3, an auxiliary element 4, made in the form of a ferromagnetic ball, is placed in the container 5, with the window 6 and the bottom 7 open for observation, made of ferromagnetic material. The permanent magnet 8, having the shape of a truncated cone, with the Hall sensor 1 located on it, forms the measuring head 9 of the device. The power supply 10 with its outputs I1, I2 is connected to the current terminals of the Hall sensor 1.

 The device operates as follows.

 The measurement object is a non-ferromagnetic plate 11 placed between the measuring head 9 and the container 5. Then the container 5 with the ball 4 located in it is centered relative to the head, moving it so that the ball is in the center of the circle, the center of which is located in the geometric center of the plate 7. When this, due to the presence of the field concentrator of magnet 8, made in the form of a truncated cone, the ball is always centered so that the axis of the ball, Hall sensor and magnet coincide despite the fact that the measuring head 9 can be the distance from the observer by the measured material 11. In this case, the magnetic flux Fr. the value of the EMF of the Hall sensor 1, the voltage at the output of the amplifier 2, and the indication of the indicator 3 change. The ferromagnetic plate 7 — the bottom of the container 5 — allows you to increase the flux of scattering through the sensor 1 with the same thickness of the measured material, and it means and allows you to increase the signal at the output of amplifier 2. This makes it possible to reduce the measurement error and expand the range of measured values in the direction of their increase.

 To ensure the operability of the device, the power supply unit 10 can be made according to the scheme of a stable current generator (see Falkenberry L. Application of operational amplifiers and linear ICs. - M .: Mir, 1985, p. 245, Fig. 9.8).

 Thus, the claimed device in comparison with the prototype provides the possibility of more accurate centering of the ball relative to the axis of the measuring head, which improves the accuracy of the measurement. In addition, the use of a ferromagnetic plate as the bottom of the container allows you to increase the range of measured values. The use of a container for placing the ball in the device allows you to adjust the pressure force of the material to the head, which expands the scope of the device for those processes where the pressure is regulated.

Claims (1)

A device for measuring the thickness of non-magnetic materials, containing a measuring head with a magnet and a Hall sensor placed on it, the signal electrodes of which are connected through an amplifier to the indicator, and current electrodes to the outputs of the power supply, a ferromagnetic element in the form of a ball located on the opposite side of the measured material, which differs the fact that the ferromagnetic ball is placed in a container with a bottom made in the form of a ferromagnetic plate and having a window open for observation.