SU542910A1 - Flow meter - Google Patents

Description

The drawing shows a diagram of the described flow meter containing a measuring tube 1 with a reinforced diaphragm 1311, a diaphragm 2 in its central opening with a gap 3, fixed to the base 4, and both ends of the axis are drawn out through snalnkp 5, sealed in sleeves 6, from poles, located outside of the diaphragm 2.

The upper end of the axis 4 is provided with a socket 7, and the lower end is rigidly connected to the bottom of the bellows 8, which is derived from the iridiadiaphragm cavity. In this case, a command cavity 9 is formed under the slide 8. The measuring tube 1 is equipped with nozzles 10 and II for the supply and removal of the medium placed in front of and behind the diaphragm 2.

The measuring circuit of the device contains a pneumatic sensor 12, powered by the compressed air of the RPTT and consisting of a membrane 13 and a regulating element 14 connected to the spring 7, pressure gauges 15 and 16, installed respectively on the compressed gas supply (Yappt) lines and its outlet (Fig. ), pressure differential controller 17, implemented as a membrane unit, for example, a USEPP element of comparison, whose membranes form a positive 18 and negative 19 chambers, as well as a task chamber 20 communicated with pressure source P.

The diaphragms of the regulator 17 control the position of the flaps 21 and 22 relative to the respective feed nozzle 23 and atmosphere-related nozzle 24. The positive chamber 18 of the regulator 17 communicates with the internal volume of the measuring tube 1 in front of the diaphragm 2 through the pressure take-off 25, and the negative chamber 19 - with the internal volume of the measuring tube I behind the diaphragm 2 through the pressure extraction port 26. The output of the differential pressure controller is communicated with the command cavity 9.

The device works as follows.

When the flow rate Q of the measured medium in the zones is changed directly by the diaphragm 2, and after it there is a change in the pressure drop AP, which is reproduced by the pressure difference regulator 17. The increase in the flow rate and pressure drop D / disrupts the balance of the membranes of the regulator 17, closing the 24, connected to the atmosphere, and opening the feed nozzle 23, as a result of which the pressure at the outlet of the regulator 17 increases. Under the action of increasing pressure in the command cavity 9, the sylphs 8 move the float 3 in the direction of increasing the annular cross section formed by the melt 3 and the walls of the orifice in the diaphragm 2. As a result, the differential pressure differential over the diaphragm decreases to the value of the PZ given in the regulator chamber 20 . In this case, the movable system of the pressure differential controller 17 is balanced. With a decrease in the flow rate and a corresponding decrease in the differential pressure, the float 3 moves iodine by the action of the bellows 8 in the direction of decreasing the annular cross section between the ion guide 3 and the walls of the orifice of the diaphragm 2. As a result, the differential pressure AP on the diaphragm 2 again becomes equal to the target.

Thus, any change in the flow rate of the measured medium corresponds to the movement of the float 3 under the action of the bellows 8 (indicated and displacement) in the zone of a constant value of nonrepetition given by the pressure differential controller 17. The movements of the ion bath 3 change the amount of compression of the spring 7, the force from which is transmitted to the membrane 13

Inevitational sensor 12. The diaphragm 13 acts on the regulating element 14, which produces an output pneumatic signal of the ROLE coming under the membrane 13 and compensating the force of the spring 7. As a result, the pneumatic signal produced is proportional to the movement of the float 3 and, consequently, to the flow rate. Since the float 3 makes forced movements under the force developed by the bellows 8, and this force is significantly greater than the frictional forces in the glands 5 and the force developed by the pressure gauge 12, the movements of the float 3 always occur before the set pressure differential controller 17 . At the same time, the operation of the flow meter is not affected by its position (it can be installed horizontally), contamination in the guide axles appearing during the operation of the device, etc.

In this way, improved accuracy in measuring low flow rates is provided.

Claims (2)

Invention Formula A flow meter containing a measuring body with a diaphragm mounted coaxially inside it, in the central opening of which there is a float mounted on the axis, the end of which is fixed on the bellows, supply and discharge connections and pressure take-off, fixed before and behind the diaphragm, differential pressure regulator, the output of which is connected to the outer cavity of the mentioned bellows, and secondary Converter, in order to improve the accuracy of measurement and expansion of the application Dianazone, both ends of the float axis are derived through glands placed in bushings from cavities dissected before and behind the diaphragm, while the upper part of the measuring tube is equipped with a pneumatic sensor of the secondary converter, consisting of a spring-loaded membrane and an adjustment element, as well as pressure gauges installed on the compressed gas supply and discharge lines, and the bellows is derived from the pre-diaphragm polo and its internal cavity is communicated with the atmosphere, and is positive and negative the differential pressure regulator chambers are respectively sludge, respectively, through pressure tapping nozzles with cavities of the measuring body located in front of and behind the diaphragm. Sources of information taken into account in the examination: 1.A. N. Pavlovsky. "The flow and quantity of liquids, gas and steam, M., 1967, p. 342-343, fig. 210. 2. US patent number 2944420, 1960, cl. 73- 209 (prototype). .t -20 -1E