SU964507A2 - Pressure difference transducer - Google Patents

Description

(54) CONVERGING1 ELECTRIC FIRST PRESSURE

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The invention relates to a measuring technique, but rather to a device for measuring the difference between liquid and gaseous media, advantageously to transducers with sensitive elements in the form of gauge boxes of unequal rigidity.

According to the main author. St. No. 775642 is known for a differential pressure transducer, comprising a housing divided by a partition into two working chambers, each of which contains pressure-sensitive elements, which form two communicating cavities with the partition, connected to a source of normalized pressure, made in the form of a manometric elastic element associated with the core of an electromagnet, and on the core of the installed limit its movement 1.

However, using a known device, dp checking the sensitivity of the transducer in an extended pressure range with sensitive elements of unequal rigidity is ineffective, since the pressure pulse generated by the source of normalized pressure NLM deforms mainly the softer sensitive element. In this case, the deformation of the second sensitive element is significantly reduced, which leads to a significant decrease in the output signal and the accuracy of sensitivity calibration. For example, a transducer with a ratio of the rigidity of pressure-sensitive elements equal to 7 and supplied with a known source of normalized pressure has an output signal

10 to 7 times smaller than that of a known transducer with sensing elements of equal hardness.

The purpose of the invention is to improve the accuracy

15 marks for extended pressure transducer range.

Claims (2)

The goal is achieved by the fact that the sensitive elements are selected with unequal rigidity, and a normally open valve connected to the core of the electromagnet is inserted into the converter, through which the cavity of the sensitive element of lesser rigidity is communicated with the pressure-sensitive elastic element 396 and the second sensitive element. The drawing shows the proposed differential pressure transmitter. The converter includes a housing 1 divided by a partition 2 into two working chambers 3 and 4, inside of which are placed pressure-sensitive elements, made in the form of manometric boxes 5 and 6, respectively, of greater and lesser rigidity, filled with liquid 7. The movable center of the box 5 is connected with the transducer 8 moving to the output signal. Gauge boxes 5 and 6 with independent channels 9 and 10 are connected to the internal cavity of the source of the standardized pressure, made in the form of a bellows 11, connected by a spring. 12 with a stepped core 13 of the electromagnet 14, the course of which is limited by the projections 15 of the partition 2. A manometric elastic element 16 is hermetically connected to a normally open valve 17 provided with openings 18. There is a gap 20 between the spring 19 and the stepped core 13 when the electromagnet is turned off. The converter operates as follows. If it is necessary to check the sensitivity of the converter, the electromagnet 14 is turned on, the pusher 13 of which, moving, initially acts through the spring 12 on the valve 17 and the bellows 11. The valve 17, moving, closes the channel 10 connecting the source of the normalized pressure with the pressure gauge box 6 of lesser rigidity. Upon further movement, the core 13 travels a distance equal to the gap 20, and begins to act through the spring 19 on the manometric elastic element 16, for example bellows, and creates a normalized pressure in the internal cavity of the manometric box 5. Under the action of this pressure, the center of the gauge box 5 is moved, which is transmitted to the displacement transducer 8 in the output signal. The relationship between the output signal of the transducer and the pressure generated in the internal cavity of the gage box 5 is determined during the manufacture and adjustment of the transducer. By the deviation of the output signal from the initial value, the change in the metrological characteristics of the converter and the need to make adjustments to its readings are judged. The use of the proposed transducer with pressure gauge boxes of unequal stiffness for measuring the pressure difference allows to significantly improve the accuracy of the sensitivity of the converter in the extended pressure range, which also makes it possible to increase the accuracy of the pressure difference measurement. The use of the proposed converter is especially useful for measuring the pressure difference between high-temperature corrosive media, since in these cases the most intense change occurs in the metrological characteristics of the instrument. In addition, the ability to automate the sensitivity calibration process allows the use of a converter in automated process control systems. The invention of the Converter pressure difference for aut. St. No. 775642, characterized in that, in order to improve the accuracy of the converter calibration for an extended pressure range, sensitive elements are selected of unequal rigidity, and a normally open valve connected to the electromagnet core is inserted into the converter, through which the cavity of the sensitive element of lesser rigidity is communicated with a manometric elastic element and the second sensitive element. Sources of information taken into account during the examination 1. USSR author's certificate for application no. 2707747 / 18-10, cl. G 01 L 13/02, 05.01.79 (prototype).