RU2281469C1 - Pressure and force meter - Google Patents

Abstract

FIELD: measurement engineering.

SUBSTANCE: pressure and force meter can be used when designing pressure and force train-measuring aids and in calibration testing circuits. Meter has load-receiving platform connected with case through rod by two resilient flat-parallel membranes. Membranes have equal effective areas; strain-measuring converter. Manometer resilient member, made in form membrane or bellows, is mounted onto rod at the same axis with load-receiving platform between two resilient flat-parallel membranes. Manometer resilient member shares case with membranes and it forms two chambers for measurement of pressure at different modes. Pressure (as well as absolute and excess pressure) and force can be measured by the same device. Pressure difference and rarefaction can be measured in analog and discrete modes of measurement.

EFFECT: improved efficiency.

2 dwg

Description

The invention relates to measuring equipment with increased accuracy and can be used in calibration complexes with computer processing of pressure and force measurements.

The essence of the invention lies in the fact that in the pressure and force meter containing a load receiving platform connected to the housing through the rod by two elastic plane-parallel membranes having the same effective area, one of which is placed strain gauge, on the rod on the same axis with the load receiving platform between two elastic plane-parallel membranes mounted gauge elastic element in the form of a membrane or bellows, connected to them by a housing and forming two chambers for measuring excess pressure and rarefaction, absolute pressure and differential pressure in analog and discrete modes.

A device for weighing is known (RU 2005292 C1, 12/30/1993), containing a base in the form of a frame with racks and two elastic elements made in the form of tapes, fixed with ends on racks, and the middle part fastened with a load receiving platform and located symmetrically relative to the longitudinal axis of the load receiving platform .

Known strain gauge pressure sensor (RU 2050743 C2, 20.12.1995), comprising a housing in which there is a manometric elastic element with a rigid center and a rod interacting with a rectangular console on which strain gages are fixed.

A common disadvantage of the known devices is their limited technical application: the weighing device can only be used for measuring weight (force), and a strain gauge pressure sensor is intended only for measuring excess pressure and vacuum in analog mode.

An object of the present invention is to measure with one device:

- strength;

- overpressure and rarefaction, absolute pressure and differential pressure in analog and discrete modes.

The problem is solved due to the fact that in the meter containing the load platform, connected to the housing through the rod with two elastic plane-parallel membranes having the same effective area, one of which is placed strain transducer, on the rod on the same axis with the load platform between two elastic flat-parallel membranes mounted gauge elastic element in the form of a membrane or bellows, connected to them by a housing and forming two chambers for measuring excess pressure and rarefied I, absolute pressure and differential pressure in the analog and digital modes.

Figures 1 and 2 show diagrams of meters that differ only in gauge elastic elements used depending on the technical, economic and metrological requirements for the device.

The meter contains a load receiving platform 1, connected to the housing 2 through the rod 3 with two elastic plane-parallel membranes 4 and 5 having the same effective area. A strain gauge 6 is placed on the membrane 5. In FIG. 1, between the two plane-parallel membranes 4 and 5 on the same axis as the load platform 1, the movable center of the gauge elastic element 7 in the form of a corrugated or flat membrane is fixed on the rod 3. In Fig.2, the manometric elastic element 7 is installed in the form of a sylphon. Two plane-parallel membranes and a manometric elastic element, rigidly connected along the outer diameter with the housing 2, form two measuring chambers 8 and 9 for measuring excess pressure and rarefaction, absolute pressure and pressure difference. The electronic unit 10 feeds the strain gauge 6, corrects the temperature error and non-linearity of the meter, introduces a correction that supports the condition of equality of the effective areas of plane-parallel membranes 4 and 5, converts the output signal of the strain gauge to an informative signal of the device.

The force F acting on the load receiving platform 1 is measured when the measuring chambers 8 and 9 communicate with the atmosphere.

Measurement of overpressure (P) and rarefaction (-P), absolute pressure and pressure difference is carried out in discrete and analog modes. In figures 1 and 2, the direction of pressure P (-P) is indicated for a discrete measurement mode. In the discrete mode, the excess pressure P is supplied to the chamber 8, the vacuum -P is created in the chamber 9. In the analog mode, the excess pressure P is supplied to the chamber 9, the vacuum -P is created in the chamber 8.

In the discrete mode, the pressure measurement P (-P) is carried out according to the compensation scheme with the value of the measured pressure corresponding to the weight of the cargo located on the load receiving platform, and each measurement in this mode is carried out with the meter output signal equal to zero, i.e. at the “zero” position of the gauge elastic element 7 and two plane-parallel membranes 4, 5. The “zero” position of the gauge elastic element and two elastic plane-parallel membranes made of nickel and titanium alloys, respectively, is maintained at various discrete values of the measured pressure in the entire range measurements, which eliminates the additional error of the meter - the error inherent in elastic elements during their movements.

Before measuring absolute pressure in the measuring chambers 8 and 9, equal vacuum is created, both chambers are evacuated.

In the discrete mode, when measuring absolute pressure, the measured pressure P is supplied to the measuring chamber 8, while in the chamber 9 a vacuum is maintained (in the analog mode of measurements, the measured pressure P is supplied to the measuring chamber 9).

In analogue mode, the pressure measurement P (-P) is carried out at any point in the measurement range in the absence of the force F (load) on the load receiving platform 1. The manometric elastic element 7, converting the measured pressure P (-P) to the force F, moves the rod 3 and two plane-parallel membranes 4 and 5, causing a change in the output signal of the strain gauge 6. In the analog mode with P (-P) equal to atmospheric, the slope of the meter output signal can be calibrated using a normalized load placed on the load receptor mold 1.

Information sources

1. Weighing device. Patent RU 2005292 C1, 12.30.1993.

2. Strain gauge pressure sensor. Patent RU 2050743 C2, 12.20.1995.

Claims (1)

A pressure and force meter containing a load receiving platform connected to the housing through the rod by two elastic plane-parallel membranes having the same effective area, a strain gauge is placed on one of them, a manometric elastic element is installed on the rod on the same axis as the load receiving platform between two elastic plane-parallel membranes in the form of a membrane or bellows, connected to them by a housing and forming two chambers for measuring overpressure and vacuum, absolute pressure and various STI pressures in analog and digital modes.

Images