SU697828A1 - Hydrostatic level gauge - Google Patents

Description

(54) HYDROSTATIC LEVEL

The invention relates to the field of instrumentation and can be used to measure and control the level of a liquid in various industries.

A hydrostatic liquid level gauge is known, containing two pressure transducers with sensing elements located in the upper and lower points of the vessel, the transducer outputs are connected to a differential circuit and a dividing device 1.

The closest to the technical essence of the invention is a hydrostatically level gauge containing a pneumatic pulse generator, a pneumohydraulic amplifier, a pulsating elastic tank filled with a separating fluid, a differential manometer with an output signal storage cell 2.

The pulsating capacitance can be structurally made in the form of a rigid metal cylinder with a bottom in the form of a loose elastic membrane that perceives hydrostatic pressure in the reservoir and is a pulsating element.

The disadvantage of this gage is that its reliability is not high enough.

Since over time, leakage and leakage of the separating fluid from the pulsating tank through the piston of the pneumohydraulic booster cannot be ruled out, which can lead to the sensor level failure. The aim of the invention is to increase the reliability of the device.

The goal is achieved due to the fact that a reservoir with a separating fluid, a piston hydraulic pump with a pneumatic actuator, the suction valve of which is connected to the specified reservoir, and the discharge valve with a working capacity, an additional generator of pneumatic impulses and a pneumorel are inserted into the gauge, limit position sensor in the left membrane, the pneumocontact of which through the pneumorel, connected according to the scheme NOT, is connected in parallel with the power line of the additional generator to the stump pulses,

Claims (5)

the output of which is connected to the pneumatic chamber of the hydraulic pump and to the control chamber of a normally open pneumatic valve installed in the power line of the generator of pneumo-pulses of the pneumohydraulic booster. The drawing shows a schematic diagram of the level gauge. It consists of a cylindrical tank 1 filled with a separating liquid, the bottom of which is hermetically sealed on the side of the reservoir with the measured liquid by an elastic in a blunt membrane 2. A permanent magnet is glued to the center of the membrane. 3. At a predetermined distance from the tank flange, corresponding to the maximum allowable deflection inside the tank 1 of the membrane 2, there is a sealed magnetically controlled pneumatic contact 4 with the nozzle 5 and a spring-loaded damper 6. The permanent magnet 3 and the pneumatic contact 4 with the nozzle and the valve form a limit position sensor loy membrane. The output of the pneumocontact 4 is connected to the control chamber of the pneumorele 7 connected according to the NOT scheme, the circuit of which additionally includes a tank 8 and an adjustable choke 9. The separating fluid, in addition to the tank 1, simultaneously fills the positive chamber of the differential pressure gauge 10 and the chamber of the pneumohydraulic amplifier 11. 10 is connected to the input of the output memory cell 12, which consists of a normally open pneumatic valve, a tank and an output amplifier. To control the operation of the pneumohydraulic amplifier 11, a generator of pneumatic pulses 13 is installed in the circuit, consisting of a pneumorele, a capacitor and an adjustable throttle. The pneumatic pump 14 consists of a double piston 15 (air separation fluid), a suction valve 16 and a discharge valve 17 connected to the tank 1. The inlet of the suction valve 16 is connected to a reservoir 18 filled with a separating fluid. The tank operates at atmospheric pressure. An additional generator 19 pneumatic pulses is provided for controlling the operation of the hydraulic pump 14. In the supply line of the generator 13 pneumatic impulses, a normally open valve 20 is installed. The gauge operates as follows: at the initial time, the tank 1, the chamber of the differential pressure gauge 10 and the tank of pneumohydraulic booster 11 are filled with separating fluid, and the membrane 2 takes a position approximately on the plane of the flange (middle dotted line ). With a Pt pulse (1 generator 13, the pneumatic-hydraulic amplifier 11 moves down to the stop, the valve of the memory cell 12 closes, the excess separation fluid flows into the tank 1, the membrane 2 moves to the extreme right position (right dashed line). With the pulse of the P 0 generator 13, the pneumatic hydraulic amplifier 11 moves up to the stop, the separation fluid under the influence of the hydrostatic pressure of the measured liquid flows into the tank of the pneumohydraulic booster, the membrane 2 returns to its original position, and the output of the output memory cell 12 is set to a pressure proportional to the hydrostatic pressure of the measured liquid equal to the product of the level by the density. At a known density, the output pressure 1 is a measure of the level. The frequency of movement of the pneumohydraulic booster (pulsation of the membrane 2) is set by setting the frequency of the generator 13 and depends on intensity of crystallization in the measured liquid or on the degree of its contamination with viscous components. As the pneumo-hydraulic booster works, the separating fluid gradually flows from the reservoir 1 into the pneumatic chamber of the amplifier 11 through the gaps in the pair of piston-hydraulic cylinder and is discharged into the atmosphere. The deflection of the membrane 2 increasingly occurs to the left in the direction of the magnetically controlled pneumocontact 4. When the leftmost position is occupied by the diaphragm (shown by a solid line), the magnet 3 attracts the flap 6, the nozzle 5 opens and the pressure in the control chamber of the relay 7 drops to atmospheric, and the supply pressure is set at the output of the relay, which causes the valve 20 to close generator 13 is turned off and generator 9 is turned on. With the pulses 1 of the generator 19, the piston of the hydraulic pump 14 through the valves 16 and 17 from the reservoir. 18 pumps the portions of the separation fluid into the container equal to the volume of the hydraulic cylinder of the hydraulic pump, while the diaphragm 2 gradually bends to the right until the valve 6 is closed by the pneumatic contact nozzle 5. After the pneumatic contact closes, in order to ensure that the magnet 3 is removed from the valve 6, the generator 19 is operated for some time and a separating fluid is pumped into the container 1. The time of additional operation of the generator is set by setting the throttles 9. After the set time has elapsed, the upper nozzle of the relay 7 closes, the atmospheric pressure is set to its output, the generator 19 is turned off and the generator 13 of the pneumohydraulic booster 11 starts up, and the membrane 2 starts to operate in a pulsating mode. Since reservoir 18 operates at atmospheric pressure, it is not difficult to replenish it periodically with a separating liquid. The invention of the hydrostatic level gauge, containing a working container with a pulsating in the left membrane, filled with a separating fluid, pneumohydraulic amplifier, a differential pressure gauge with a memory cell