RU2797143C1 - Compensated volumetric gas meter - Google Patents

Abstract

FIELD: gas engineering.

SUBSTANCE: invention can be used in gas supply systems for industrial and domestic consumers. A distinctive feature of the proposed compensated volume meter is the implementation of the meter readings corrector in the form of a gas-tight corrugation placed in a vertical container, mounted in a hard disk, with one end attached to the upper part of the container, and the other end connected by means of a leash to a plate in the form of a right-angled triangle installed with the ability to move along the axis of the container in guides fixed on the outer side of the container, so that the plane of the plate coincides with the plane of rotation of the levers for connecting the membrane with the slider, the plate touches the plane of the container with one leg, and the acute angle of the plate adjacent to this leg is directed upwards, moreover the corrugation is filled with such an amount of gas that, at normal pressure and normal temperature, the axis of the membrane passes through the middle of the leg adjacent to the plane of the container.

EFFECT: equipping the gas meter with an indication corrector providing correction both in terms of temperature and gas pressure.

1 cl, 2 dwg

Description

The invention relates to gas engineering and can be used in gas supply systems for industrial and domestic consumers.

A volumetric gas meter [1] is known, containing two chambers, each separated by an elastic membrane into two cavities, alternately switched by a switch from the outlet to the inlet pipes of the meter. At the same time, while one of them is filled with a fixed portion of gas, the second gives this portion to the consumer. Released gas is accounted for by the number of cavity switching cycles.

However, in this counter, the time during which the cavities switch from the period of filling to the period of gas return is comparable to the cycle time. Therefore, in order to exclude direct (bypassing the cavities) passage of gas from the line to the consumer during switching, the switch first closes the outlets of both cavities, then also relatively slowly opens them one from filling to gas return, the second - from return to filling. And so that the gas supply to the consumer during the switching is not interrupted, a second chamber is installed in the meter in parallel, the filling and emptying cycle in which is shifted with respect to the filling cycle of the first chamber by a quarter of the period. This doubles the dimensions and number of parts of the meter, which ultimately increases its burdensome cost for the consumer and reduces reliability.

The volumetric gas meter according to patent No. 2779382 [2] is free from this drawback. It contains a chamber divided by an elastic membrane with a central part in the form of a hard disk into the first and second cavities, a mechanical reading device, a bimetallic temperature corrector of the meter readings, a slider for switching cavities from the meter outlet to the inlet branch pipes, a switch seat, the two extreme windows of which are connected respectively with the first and second cavities, and the middle one - with the meter outlet pipe, the levers for connecting the membrane with the slider, the converter of the reciprocating movement of the slider into the rotational movement of the input shaft of the mechanical readout device, the meter calibration device, the temperature corrector is made in the form of 2 bimetallic plates, rigidly attached at one end to two sides of the diaphragm disc so that the other ends of the plates are oriented along the axis of the disc, the connection levers of the diaphragm plate and the slider are springy and movably connected to the slider through the extreme windows of the switch seat, attached to the ends of the slider in the direction of its movement from both sides ferromagnetic plates interacting with permanent magnets installed opposite each of them on the switch seat, with the possibility of adjusting the gap between the poles of the magnets and the ferromagnetic plates by means of screws that act as a meter calibration device, and the converter of the reciprocating motion of the slider into the rotational motion of the input shaft of the mechanical reference The device is made in the form of a ratchet mechanism.

Volumetric gas meters measure the volume of released gas, while both the consumer and the supplier are interested in a more objective indicator of its quantity - the mass of gas. However, according to the Klaiperon-Mendeleev equation

или

,

or

,

where V is the volume of gas, m ³ ;

Р - gas pressure, Pa;

T - gas temperature, K;

Z = P / T - generalized disturbing factor, Pa/K;

R is the gas constant equal to 286.69 J/(kg⋅K);

m - mass of gas, kg,

The relationship between volume and mass is ambiguous. The perturbing factors are pressure and temperature of the gas. Calculations show that in the range of possible changes in gas temperature, the measurement error is ±7%, and in the range of pressure changes - ±6%. Therefore, most volumetric gas meters are equipped with bimetallic temperature error correctors, while there is no correction of meter readings depending on the pressure value.

The purpose of the proposed invention is to eliminate this disadvantage, namely: equipping the gas meter with a reading corrector that provides correction, both in temperature and in gas pressure.

The technical result is achieved due to the fact that in a compensated volumetric gas meter containing a chamber divided by an elastic membrane with a central part in the form of a hard disk into the first and second cavities, a mechanical reading device, a corrector for the meter readings, a slider for switching cavities from the outlet to the inlet pipes of the meter , a switch seat, the two extreme windows of which are connected to the first and second cavities, respectively, and the middle one - to the outlet pipe of the meter, the levers for connecting the membrane with the slider, the converter of the reciprocating movement of the slider into the rotational movement of the mechanical reading device, the meter calibration device, springy connection levers diaphragm and slider plates movably connected to the slider through the extreme windows of the switch seat, to the ends of which, in the course of its movement, ferromagnetic plates are attached on both sides, interacting with permanent magnets installed opposite each of them on the switch seat, with the possibility of adjusting the gap between poles of magnets and ferromagnetic plates by means of screws that act as a meter calibration device, made in the form of a ratchet mechanism, a converter of the reciprocating movement of the slider into the rotational movement of the input shaft of a mechanical reading device , the corrector of the meter readings is made in the form of a vertical container mounted in a hard disk, sealed gas-filled corrugation, one end attached to the upper part of the container, and the other end connected by means of a leash to a plate in the form of a right-angled triangle, mounted for movement along the axis of the container in guides fixed on the outer side of the container, so that the plane of the plate coincides with the plane of rotation levers for connecting the membrane with the slider, the plate touches the plane of the container with one leg, and the acute angle of the plate adjacent to this leg is directed upwards, and the corrugation is filled with such an amount of gas that at normal pressure and normal temperature the axis of the membrane passes through the middle of the container adjacent to the plane leg.

The essence of the proposed invention is illustrated by the drawing (Fig. 1 - front view and Fig. 2 - top view of the switch).

The counter contains a chamber 1 divided by an elastic membrane 2 with a central part in the form of a hard disk 3 into the first 4 and second 5 cavities. The slider 6 of the switch of cavities from the outlet 7 to the inlet 8 branch pipes of the counter is mounted with the possibility of shifting to the right and left on the saddle 9 of the switch, the two extreme windows of which 10 and 11 are connected respectively with the first 4 and second 5 cavities, and the middle 12 - with the outlet branch pipe of the counter. The slider 6 on the side adjacent to the saddle has a channel 13 connecting windows 10 and 12 in the extreme left position of the slider, and windows 11 and 12 in the extreme right position. The levers 14 and 15 are springy, movably connected to the slider 6 through the extreme windows 10 and 11 saddles 9 derailleurs. The ratchet wheel 16 is mounted on an axis rigidly connected to the saddle 9 of the cavity switch, and serves to convert the reciprocating motion of the slider 6 into rotational motion of the input shaft of the mechanical readout device (not shown in the drawing). Ferromagnetic plates 17 and 18 are attached to the ends of the slider 6 in the direction of its movement on both sides, interacting with permanent magnets 19 and 20, respectively, installed opposite each of them on the saddle 9 of the switch. The gap between the poles of the magnets and the ferromagnetic plates is adjusted by means of screws 21 and 22, which act as a meter calibration device.

A cylindrical container 23 is mounted in the central part of the hard disk 3, the axis of which coincides with the vertical axis of symmetry of the hard disk. Corrugation 24 is placed coaxially inside the container, the upper end of which is attached to the upper part of the container, and the lower end is connected with a plate 26, which has the shape of a right triangle, by means of a rigid leash 25. The plate is installed with the possibility of movement along the container in the vertical direction in the guides 27 fixed on the outer surface of the container. The plane of the plate coincides with the plane of rotation of the levers for connecting the membrane with the slider. The plate touches the plane of the container with one leg, and the acute angle of the plate adjacent to this leg is directed upwards. The cavity of the corrugation is connected with the cavity 4 through the hole 28 of small diameter (1...2 mm), equalizing the pressure outside and inside the corrugation. In a free state, with equal pressures inside and outside the corrugation (hole 28 is open), under the influence of the weight of the corrugation and the corrugation plate, the corrugation should occupy at least 80% of the length of the container, and the middle of the side of the plate adjacent to the plane of the container should lie on the center line of disk 3. in this position of the plate and corrugation, cavities 4 and 5 and the corrugation cavity are filled with gas at normal pressure ( P ₀ =101325 Pa) and normal temperature ( T ₀ =273.16 K). Hole 28 is securely closed (eg by soldering).

All parts of the inventive gas meter are placed in a housing forming a gas intake compartment 29 and a gas flow compartment 30, separated by a window 12 of the switch seat 9.

The volumetric gas meter works as follows.

Let us assume that the pressure and temperature of the gas passing through the meter correspond to normal values ( P ₀ and T ₀ ). Let us also assume that at the initial moment of time the slider 6 of the switch is held in the extreme left position by the magnetic interaction of the magnet 19 and the ferromagnetic plate 17, as shown in the figure, and the membrane is in the extreme right position (position 0-0). At the same time, window 11 is open and gas from compartment 29 begins to flow into cavity 5. The membrane moves under gas pressure from right to left, displacing the gas filling cavity 4 through windows 10 and 12 connected through channel 13 into compartment 30 and further to the consumer. As soon as the edge (hypotenuse) of the plate 26 touches the lower end of the lever 14, the deformation of the lever will begin (with further movement of the membrane), accompanied by an increase in the force of interaction between the lever and the plate 26, and, consequently, an increase in the pressure force of the upper end of this lever on the slider 6. When filling cavity 4 with a predetermined fixed volume V ₀ of gas (the membrane at this moment will take position Y ₀ - Y ₀ ), the calculated mass of gas will be transferred to the consumer

where S _m is the area of the membrane, m ² ;

Y ₀ - nominal stroke of the membrane, m.

The rigidity of the lever arms is calculated in such a way that at this moment the force of the lever on the slider 6 of the switch will exceed the force of attraction of the ferromagnetic plate 17 to the magnet 19 and the slider will abruptly move to the extreme right position. From this moment, cavity 4 will be filled with gas through the opened window 10 and cavity 5 will be emptied through windows 11 and 12. The slider will move to the initial left position in the same way as described above, completing one of the cycles alternating one after another. In this case, the ratchet wheel 16 of the drive of the mechanical reading device rotates by one tooth per cycle, corresponding to the transfer of a mass of gas equal to 2 m _p to the consumer.

Since the pressure and temperature of the gas inside and outside the corrugation are the same, there is no change in the length X ₀ of the corrugation.

When the temperature and pressure of the gas deviate, the mass flow rate of the gas at the same volume of consumption changes, which leads to the appearance of an error in the flow measurement. Therefore, in order to compensate for the error, it is necessary to change the degree of filling of cavities 4 and 5 proportionally to Z.

In accordance with the Klaiperon-Mendeleev equation ( PV/T = mR = Const) for the working cavities of the counter, we have

Where

And the increase in membrane travel

Similarly for the cavity of the corrugation with its very low rigidity

Thus, the movement of the corrugation, and, consequently, the plate 26 by ∆ X will lead to a corresponding movement of the membrane by ∆ Y, if the angle α of the plate rib is equal to arctg(∆ Y / ∆ X ). In this case, the course of the membrane will change and, consequently, the volume of the gas portion, and the mass will remain constant, equal to the calculated value m _p for a counter of certain dimensions. It is important in this case, in order to avoid slippage of the plate in contact with the lever 14, the angle α must be less than the angle of friction of the contacting surfaces. To do this, the length of the corrugation X ₀ must be much greater than the stroke of the membrane Y _0.

The dimensions of the legs of the plate are determined depending on the ranges of pressure and temperature changes in the places where the operation of the meter to be manufactured is supposed to be. So for the leg opposite the angle α,

where

∆Xmax ₌ ∆Xmax _/ tanα

Setting the accuracy of the readings of the claimed volumetric gas meter is carried out by screws 21 and 22, with the help of which the gaps between the ferromagnetic plates and magnets are changed. With a decrease in the gap, the force of their mutual attraction increases, therefore, to tear off the slider, a more complete filling of the volumes of the cavities is required. This action eliminates the overestimation of the gas meter readings in comparison with its actual consumption. And vice versa, if the meter gives underestimated readings, it is necessary to increase the gaps between the plates and magnets.

Thus, in the claimed volumetric gas meter, error compensation is carried out in the ranges of temperature and pressure changes required by operating conditions, not only in temperature, but also in pressure.

Information sources

1. Passport 8181.00.000 PS, DIAPHRAGM GAS METER WITH THERMAL COMPENSATOR SGD-3T// Open Joint Stock Company “Minsk Mechanical Plant named after S.I. Vavilova is the managing company of the BelOMO holding.

The counter is included in the state registers of: the Republic of Belarus (registration number RB 03 07 3632 14); Russian Federation (registration number 39093-13).

2. Patent for invention No. 2779382. Volumetric gas meter / Petko V.G., Rakhimzhanova I.A., Fomin M.B., Pugachev V.V., Kononets V.V. Patentee: Orenburg Agrarian University » Published 09/06/2022 Bull. No. 25.

Claims (1)

Compensated volumetric gas meter, containing a chamber divided by an elastic membrane with a central part in the form of a hard disk into the first and second cavities, a mechanical reading device, a corrector for meter readings, a slider for switching cavities from the outlet to the inlet branch pipes of the meter, a switch seat, the two extreme windows of which are connected with the first and second cavities, respectively, and the middle one with the meter outlet pipe, levers for connecting the membrane with the slider, a converter of the reciprocating movement of the slider into the rotational movement of a mechanical reading device, a meter calibration device, spring-loaded levers for connecting the diaphragm plate and the slider, movably connected to the slider through the extreme windows of the switch seat, to the ends of which, in the direction of its movement, ferromagnetic plates are attached on both sides, interacting with permanent magnets installed opposite each of them on the switch seat, with the possibility of adjusting the gap between the poles of the magnets and the ferromagnetic plates by means of screws that perform the role of the meter calibration device, made in the form of a ratchet mechanism, the converter of the reciprocating movement of the slider into the rotational movement of the input shaft of the mechanical reading device, characterized in that the corrector of the meter readings is made in the form of a sealed corrugation filled with gas placed in a vertical container, mounted in a hard disk, one end attached to the upper part of the container, and the other end connected by means of a leash to a plate in the form of a right-angled triangle, installed with the possibility of movement along the axis of the container in guides fixed on the outer side of the container, so that the plane of the plate coincides with the plane of rotation of the levers of the connection of the membrane with the slider , the plate touches the plane of the container with one leg, and the acute angle of the plate adjacent to this leg is directed upwards, and the corrugation is filled with such an amount of gas that, at normal pressure and normal temperature, the membrane axis passes through the middle of the leg adjacent to the plane of the container.

Images