CN102252736B

CN102252736B - Constant-pressure liquid source device containing overflow groove in pressure container

Info

Publication number: CN102252736B
Application number: CN 201110187812
Authority: CN
Inventors: 王可崇
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-06
Filing date: 2011-07-06
Publication date: 2013-01-23
Anticipated expiration: 2031-07-06
Also published as: CN102252736A

Abstract

The invention discloses a constant-pressure liquid source device containing an overflow groove in a pressure container, the device adopts the structure of the overflow groove in the pressure container for getting stable liquid level and keeping pressure gas acted on the stable liquid level constant, therefore, a constant-pressure liquid source has the flow stability of the water tower pressure stabilization method and the advantage of being capable of getting high Reynolds number calibration liquid of the gas-liquid container pressure stabilization method, the cost and the floor area are less than those of the water tower pressure stabilization pressure, the high Reynolds number calibration liquid can also be obtained, the precision of stable flow is also better than that of the gas-liquid container pressure stabilization method, the constant-pressure liquid source uses a differential pressure transmitter to measure the pressure difference between the pressure of the pressure container and the pressure of a constant-pressure container, a relevant control device is used for controlling according to the pressure difference and then the gas pressure in the pressure container also has very high stabilization precision. The constant-pressure liquid source can not only be used as a standard calibration device for a variety of liquid flowmeters, but also be directly used for measurement, thereby having a wide range of applications.

Description

Pressure vessel includes the constant pressure liquid body source device of overflow groove

One, technical field

The present invention relates to a kind of constant pressure liquid body source device in flow metering standard technique field.

Two, background technology

In the national economy every profession and trade, along with industrial production automation, the development of channelization, the use amount of various forms of flow-meters is increasing.In order to guarantee data that flowmeter is surveyed accurately and reliably, must regularly on the flow standard calibrating installation, examine and determine these flowmeters.Wherein, the calibrating of fluid flow is very high to the discharge stability requirement of fluid supply, so the fluid supply of device for calibrating liquid flowmeters " water tower method " commonly used produces.Water pump is delivered to the head-tank of water tower with the water of low pool, and in whole verification process, head-tank is in overflow situation, thereby has produced the constant voltage water source of a constant water level.The characteristics of this fluid supply are easy to operate, and effect is also relatively good.But by the relation of flow and pressure head as can be known, wanting has higher Reynolds-number test scope, will build higher water tower, and this needs very large investment.For this reason, another kind of fluid supply based on " gas-liquid container voltage stabilizing method " also often is used.Gas, two spaces of liquid are arranged in the pressure vessel, and top is the gas with certain pressure, and the bottom is the liquid that is entered by infusion.The part of filling liquid is sent into test pipe calibrating flowmeter as test(ing) liquid by the selected flow of flow control valve, and all the other liquid flow back to the pond by surplus valve.If the liquid level in the container is h, gaseous pressure is p, and the density of liquid is ρ, and then the pressure head of test(ing) liquid is H=h+p/ ρ g.Because common p/ ρ g＞＞h, like this, need not just can obtain very high test(ing) liquid pressure head by high water tower.Usually with the gaseous pressure p of differential pressure transmitter inspection instrument, when it is higher or lower than normal pressure, regulate spillway discharge by regulator and topworks, stable to keep pressure head.The precision of steady current of gas-liquid container voltage stabilizing method is not as the water tower method.

Three, summary of the invention

Consider that the pond that is in overflow situation in the water tower method can obtain stable water level (pressure), but limitation in height makes it be difficult to obtain calibrating liquid than high reynolds number, and the gas-liquid container voltage stabilizing method can make calibrating liquid reach very high Reynolds number.Therefore, in the constant pressure liquid body source of development, adopt and in pressure vessel, establish run-off to obtain constant h, manage simultaneously to keep container inner pressure gas at constant p/ ρ g.When the stability of gaseous pressure p/ ρ g in the pressure vessel within the calibrating time with the degree of stability of atmospheric pressure near the time, the degree of stability of this fluid supply pressure head H will be suitable with the water tower method.

Shown in Figure 1 in the technical solution adopted in the present invention such as the Figure of description: the device of development is the constant pressure liquid body source device that a kind of pressure vessel includes overflow groove, in a pressure vessel, be filled with the pressed gas from compressed air source, container top is equipped with a pressure overflow groove to obtain stable liquid level, the container bottom is provided with the pressure hopper, liquid in the pressure hopper is driven by circulation pipe injection pressure overflow groove by ebullator, the liquid part of these injections flows out by outlet as the calibrating liquid of constant pressure liquid body source output, the pressure hopper is flowed back in the overflow that another part becomes the pressure overflow groove, there is a normal pressure hopper pressure vessel outside, liquid in the normal pressure hopper is from inlet tube, act on atmospheric pressure on the liquid level in the groove, the liquid in the normal pressure hopper by supercharge pump through non-return valve pump-in pressure hopper.The constant pressure liquid body source device that pressure vessel includes overflow groove should dispose and can detect and the relevant measure and control device of controlled pressure gas in container pressure.

The invention has the beneficial effects as follows, the constant pressure liquid body source device that pressure vessel includes overflow groove can have the discharge stability that is equivalent to water tower constant pressure liquid body source, avoided again simultaneously the investment of water tower method constant pressure source many, take up space and ground greatly, the water tower limitation in height is difficult to reach the defective of high reynolds number.The constant pressure liquid body source that the present invention both can be used as the liquid meter standard calibrating device also can be directly used in measurement, and range of application is wide.

Four, description of drawings

Fig. 1 is structural representation of the present invention.

Fig. 2 is the structural representation of the liquid meter standard calibrating device take the present invention as fluid supply.

At Fig. 1, among Fig. 2: 1. outlet, 2. pressure overflow groove, 3. pressure vessel, 4. compressed air source, 5. circulation pipe, 6. ebullator, 7. pressure hopper, 8. up and down level switch, 9. inlet tube of hopper, 10. normal pressure hopper, 11. supercharge pumps, 12. non-return valve, 13. differential pressure transmitter, 14. positive valves, 15. equalizing valves, 16. negative pressure valve, 17. pressure vessels, 18. master gauges, 19. operating valve, 20. flow control valves, 21. adjusting flowmeters, 22. constant flow meter to be checked, 23. test section, 24. normal pressure overflow grooves, 25. standard weighing containers, 26. the standard weighing container liquid level gauge, 27. calibrating valves.

Five, embodiment

Following content by reference to the accompanying drawings 1,2 pair of the specific embodiment of the present invention is described further.

In Fig. 1, pressure vessel 3 is low pressure vessel, adopts airtight cylinder-like structure, and pressure overflow groove 2 adopts the open circles barrel structure, and its diameter is installed by the identical central axis less than 3, two cylinders of pressure vessel.Distance between pressure overflow groove 2 outer walls and pressure vessel 3 inwalls is large (suggestion is greater than 0.1m, because the overflow of overflow groove also flows down along its outer wall) enough, so that annulus between the two can guarantee that pressure vessel 3 tops are consistent with the air pressure of bottom.The design volume of pressure overflow groove 2 should guarantee when maximum flow, and the liquid particle can be in the pressure overflow groove sufficiently long time of 2 interior stops, so as to allow carry in the pumping liquid into gas have ample time and discharge, this residence time is generally selected 3 minutes.The outlet 1 that the design height of pressure overflow groove 2 will guarantee the latus rectum maximum when maximum flow not the reason suction produce eddy current, general desirable h/DN 〉=10, such as the latus rectum DN=0.3m of maximum outlet 1, its design height h=3m then.Pressure overflow groove 2 tops are spoke-like and arrange some overflow groove (prior arts at surface level, not shown in FIG.), ebullator 6 by circulation pipe 5 with liquid from pressure hopper 7 bottom sinker (prior arts, not shown in FIG.) send in the pressure overflow groove 2, partially liq (its pressure head is that the height on overflow groove edge adds low-pressure gas pressure head in the upper container) enters test pipe by outlet 1, unnecessary liquid is by the overflow groove edge, then by overflow groove, flow back to pressure hopper 7 along pressure overflow groove 2 outer walls at last.Liquid in the normal pressure hopper 10 acts on atmospheric pressure from inlet tube 9 on the liquid level, supercharge pump 11 passes through non-return valve 12 with normal pressure hopper 10 interior liquid pump-in pressure hoppers 7.The relevant measure and control device of detection and controlled pressure gas in container pressure adopts current a kind of method commonly used substantially, can certainly adopt other suitable methods.Owing to measure the relation of range, gaseous tension is the control accuracy that does not reach requirement in the working pressure transmitters sense pressure vessel, thereby usually adopts the method with the pressure differential between differential pressure transmitter 13 gaging pressure containers 3 and the pressure vessel 17.The plemum of differential pressure transmitter 13 passes to pressure vessel 3 through positive valve 14, and the negative pressure chamber of differential pressure transmitter 13 passes to pressure vessel 17 through negative pressure valve 16.Before the use, at first open positive valve 14, negative pressure valve 16 and equalizing valve 15, pressure vessel 3 is communicated with pressure vessel 17, compressed air source 4 is to these two container inflations, when the pressure in the master gauge 18 demonstration pressure vessels 17 reaches setting value, close equalizing valve 15, differential pressure transmitter 13 is in measures two normal operating conditionss that container pressure is poor.Because it is constant to require the volumetric standard internal gas pressure substantially to keep in the course of the work, therefore, except guaranteeing that volumetric standard substantially without leaking, also should have insulation and constant temperature measures, to avoid just producing measuring error when ambient temperature has subtle change.Supercharge pump 11 is variable-frequency control pump, fluid level control device (not shown in FIG.) can be higher or lower than according to the air pressure in the pressure vessel 3 situation of volumetric standard 17 internal gas pressures, reduce or increase the amount of liquid of the pump-in pressure hopper 7 of supercharge pump 11, so that the gas-phase spaces in the pressure vessel 3 increase or dwindle, and then keep air pressure in the pressure vessel 3 on setting value.Liquid level in pressure hopper 7 is higher or lower than the up and down liquid level of regulation and prescribes a time limit, up and down level switch 8 actions of hopper, after fluid level control device receives this actuating signal, control compressed air source 4 bleeds off to pressure vessel 3 inflation or with the unnecessary gas in the container, and liquid levels in the pressure hopper 7 are come back in the controlled scope of supercharge pump 11.

The present invention can be used as the constant pressure liquid body source of plurality of liquid flowmeter standard calibrating device, and it both can be used for static volume (quality) method, also can be used for dynamic volume (quality) method.In Fig. 2, only introduce the application of the present invention in a liquid meter standard calibrating device as an example of the dynamic volume method example.Static method is compared with dynamic method, and the accuracy of static method is higher, and this is because static method can be eliminated the impact of liquid remaining kinetic energy, and liquid is static metering, with pipe system without any mechanically contact.But the metering process of static method is interrupted, expends time in; And the metering process of dynamic method is continuous, easily is automated.Impulsive force when flowing to standard weighing container 25 for reducing liquid, this liquid meter standard calibrating device is provided with normal pressure overflow groove 24 to absorb the impulsive force of calibrating liquid, calibrating liquid is that the form with the overflow of normal pressure overflow groove 24 flows into standard weighing container 25, because kinetic energy and the potential energy of this overflow all weaken greatly, its impulsive force to standard weighing container 25 also greatly weakens (measure that in fact it is further weakened).The course of work of this liquid meter standard calibrating device is as follows: in advance constant flow meter 22 to be checked is installed on the test section 23, after more several calibrating flow points of constant flow meter 22 to be checked being pre-entered into industrial computer (not shown in FIG.), whole verification process just will carry out under the control of industrial computer automatically.Industrial computer is on certain calibrating flow point, at first open pneumatic operating valve 19 and pneumatic calibrating valve 27, start cycles pump 6 and supercharge pump 11 go adjust flux variable valve 20 apertures according to the flow value of regulating with flowmeter 21 actual measurements, make at last stability of flow on the calibrating flow point that requires.Behind stability of flow, industrial computer is controlled pneumatic calibrating valve 27 and is closed, liquid level in the standard weighing container 25 rises, measure this liquid level with standard weighing container liquid level gauge 26, avoiding pneumatic calibrating valve 27 closes initial stage pressure and changes the unsettled period, two liquid levels in the stable liquid level constant interval that rises of selection pressure begin liquid level as timing and timing finishes liquid level, thereby obtain and these two timing times that liquid level is corresponding.Because the liquid volume between these two liquid levels is known in advance in standard weighing container 25, so after obtaining timing time by timing, just can be regarded as to such an extent that this calibrating flow is put accurately flow value, and remove to compare the output signal value of constant flow 22 correspondences to be checked in this value.After recording timing end liquid level, namely calibrating valve 27 should be reopened, ready for examine and determine next time.Finish on request constant flow meter 22 to be checked after the calibration operation of this calibrating flow point, industrial computer is with regard to the calibration operation of the next calibrating of this flowmeter of auto-steering flow point, and its course of work is the same.

Claims

1. a pressure vessel includes the constant pressure liquid body source device of overflow groove, comprise pressure vessel (3), pressure overflow groove (2) and pressure hopper (7), it is characterized in that: in a pressure vessel (3), be filled with the pressed gas from compressed air source (4), container top is equipped with a pressure overflow groove (2) to obtain stable liquid level, the container bottom is provided with pressure hopper (7), liquid in the pressure hopper (7) is driven by circulation pipe (5) injection pressure overflow groove (2) by ebullator (6), the liquid part of these injections flows out by outlet (1) as the calibrating liquid of constant pressure liquid body source output, pressure hopper (7) is flowed back in the overflow that another part becomes pressure overflow groove (2), there is a normal pressure hopper (10) pressure vessel (3) outside, liquid in the normal pressure hopper (10) is from inlet tube (9), act on atmospheric pressure on the liquid level in the groove, through non-return valve (12) pump-in pressure hopper (7), pressure overflow groove (2) all is arranged at pressure vessel (3) inside with pressure hopper (7) to liquid in the normal pressure hopper (10) by supercharge pump (11).

2. pressure vessel according to claim 1 includes the constant pressure liquid body source device of overflow groove, it is characterized in that: the constant pressure liquid body source device that pressure vessel includes overflow groove should dispose and can detect and the relevant measure and control device of the interior gaseous tension of controlled pressure container (3).