CN102121539A

CN102121539A - Pre-inflatable pneumatic reversing valve

Info

Publication number: CN102121539A
Application number: CN201010605998XA
Authority: CN
Inventors: 李传经; 岳坚
Original assignee: Shanghai Institute of Process Automation Instrumentation
Current assignee: Shanghai Institute of Process Automation Instrumentation
Priority date: 2010-12-27
Filing date: 2010-12-27
Publication date: 2011-07-13

Abstract

The invention discloses a pre-inflatable pneumatic reversing valve which comprises a valve body, a valve plug, a piston, a first valve bank, a second valve bank, a photoelectric dispatching device and a baffle plate, wherein the piston is fixedly integrated with the valve plug; the first valve bank and the second valve bank are formed by a first valve cover respectively with a first valve seat and a second valve seat; and baffle plate is matched with the photoelectric dispatching device and is fixedly integrated with the valve plug. The pre-inflatable pneumatic reversing valve is characterized in that the right side of the second valve bank is added with a third valve bank which is composed by a third valve seat and a fixed valve cover; the first valve cover is a movable valve cover; the left side of the movable valve cover is connected with a fixed block through a spring which is sleeved on the valve plug; and the valve plug at the right side of the movable valve cover is fixedly provided with a retainer ring. The invention has the beneficial effects that when a critical flow meter is detected with a PVTt (pressure, volume, temperature, time) method gas flow calibration facility by the pre-inflatable pneumatic reversing valve provided by the invention, the introduced unstable state and possible generated additional error in the flow rate building process when in the detection at the beginning are reduced.

Description

A kind of air operated reversing valve of pre-gas-filled type

Technical field

The present invention relates to a kind of air operated reversing valve of pre-gas-filled type, belong to valve technology field.

Background technique

PVTt method gas flow standard device is a kind of highi degree of accuracy standard set-up of measurement gas mass flow rate, its predominant use is the discharge coefficient that is used to examine and determine critical flow prover (sonic nozzle that promptly it has often been said), PVTt method gas flow standard device needs to use a kind of three-way diverter valve in use and between tested accordatura speed nozzle and the calibrating container, but three-way diverter valve used in the prior art is just done a simple stream switching.When switching beginning, nozzle throat is not also set up specified calibrating flow, and this will form a gauging error.

Summary of the invention

The object of the invention in order to ensure critical flow nozzle when entering the calibrating state, the throat of critical flow nozzle has set up specified calibrating flow, minimizing flow when beginning to examine and determine is set up unstable state and the issuable complementary error that process is introduced, and a kind of air operated reversing valve of pre-gas-filled type is provided.

Technological scheme of the present invention is, a kind of air operated reversing valve of pre-gas-filled type, comprise valve body, spool, the piston that is fixed as one with spool, by first valve gap respectively with first valve seat, the first valve group and the second valve group that second valve seat is formed, the photoelectricity signal transmitter and and the photoelectricity signal transmitter baffle plate that matches and be fixed as one with spool, be characterized in, in the right side addition of the second valve group by by the 3rd valve seat and fixing the 3rd valve group formed of valve gap, described first valve gap is movable valve gap, described movable valve gap passes on left the spring that is enclosed within on the spool and is connected with fixed stop, is fixedly equipped with a back-up ring on the spool on movable valve gap right side.

The invention has the beneficial effects as follows, the present invention is a kind of air operated reversing valve of pre-gas-filled type, examining and determine the critical flow timing with PVTt method gas flow standard device, minimizing flow when beginning to examine and determine is set up unstable state and the issuable complementary error that process is introduced.

Description of drawings

Fig. 1 is the air operated reversing valve calibrating standby condition schematic representation of pre-gas-filled type;

Fig. 2 is the air operated reversing valve calibrating view of pre-gas-filled type;

Fig. 3 is changes in flow rate figure.

Embodiment

By Fig. 1, shown in Figure 2, a kind of air operated reversing valve of pre-gas-filled type, the first valve group V that comprises piston 11 that valve body 5, spool 13 and spool 1 be fixed as one, forms with first valve seat 15, second valve seat 6 respectively by first valve gap 14 ₁With the second valve group V ₂, photoelectricity signal transmitter 2 and and photoelectricity signal transmitter 2 baffle plate 1 that matches and be fixed as one with spool 13, be characterized in, at the second valve group V ₂The right side addition by by the 3rd valve seat 10 and fixing the 3rd valve group V that forms of valve gap 9 ₃, described first valve gap 14 is movable valve gap, described movable valve gap passes on left the spring 6 that is enclosed within on the spool 13 and is connected with fixed stop 8, is fixedly equipped with a back-up ring 3 on the spool 13 in movable valve gap left side.

Be the gas gross strictness that guarantee to flow into the calibrating container equal in the calibrating time, the to flow through gas gross of nozzle, and the asymmetric annex error introduced of minimizing of trying one's best because of turn around time, described photoelectricity signal transmitter 2 is made up of three optoelectronic switches, correspond respectively to initial sender, timing sender, stop sender, the optoelectronic switch that adopts the neutral position is as the timing sender.

Working principle of the present invention:

As shown in Figure 1 and Figure 2, when beginning to examine and determine, the piston 11 in the driving cylinder 12 to the right

Move the 3rd valve group V ₃Open immediately, gas is by the 3rd valve group V ₃Enter " the preparation container " that be under the vacuum state.At this moment, can set up critical flow in sonic nozzle 4 throats.The first valve group V ₁The place is because of the effect of spring, the first valve group V ₁Still be in closed condition, thereby gas can not enter the calibrating container.Piston 11 in driving cylinder 12 continues to move to right, and ring washer forces the first valve group V ₁The spool 13 at place also moves to right and closes the second valve group V ₂At this moment, gas can not continue to enter that " the preparation container and enters the calibrating container, the beginning verification process.After calibrating finishes, when being about to stop (promptly examine and determine pressure in the container rise to threshold state), the pistons 11 in the cylinder 12 move to left and at first close the first valve group V ₁, this moment, nozzle throat still kept critical flow, than the first valve group V ₁Slightly lag and close the 3rd valve group V ₃, until the 3rd valve group V ₃Be closed.Be reduced in when beginning to examine and determine flow greatly and set up unstable state and the issuable complementary error that process is introduced.

Reduce error by principle: according to the principle of PVTt method calibrating sonic nozzle and the principle of continuity in the fluid mechanics, the gas of (for example: the t=60 second) nozzle of flowing through also flows into the calibrating container in the time of one section setting, and the gaseous mass of the nozzle of promptly flowing through equals to examine and determine the collected gaseous mass of container; Therefore (that is: the critical flow of nozzle equals: q=m/t) can to carry out assignment divided by special time (that is: m/t) to nozzle according to the gaseous mass in the container.Because the volume (V) of container is through accurate given value of demarcating, pressure (P) in the container, the temperature (T) in the container can accurately be measured, therefore can calculate the gas flow that flows into container according to " equation of state of perfect gas ", this flow is " reference value ", and obtains the certified value of nozzle according to this value.The prerequisite of this verification process is: when gas flows into the calibrating container (when beginning to examine and determine), the nozzle place must set up stable critical flow (q), the previously used three-way valve of the present invention does not have pre-aerification function, and the present invention improves existing three-way diverter valve, and desired function can be realized.Fig. 3 shows: when " the metering time lag ", initial sum (t) stopped, the nozzle place had set up stable critical flow, sees: " by the changes in flow rate of sonic nozzle " figure among Fig. 3.

Claims

1.. the air operated reversing valve of a pre-gas-filled type, the first valve group V that comprises piston (11) that valve body (5), spool (13) and spool (1) be fixed as one, forms with first valve seat (15), second valve seat (6) respectively by first valve gap (14) ₁With the second valve group V ₂, photoelectricity signal transmitter (2) and and photoelectricity signal transmitter (2) baffle plate (1) that matches and be fixed as one with spool (13), it is characterized in that, at the second valve group V ₂The right side addition have by the 3rd valve seat (10) and fixing the 3rd valve group V that forms of valve gap (9) ₃, described first valve gap (14) is movable valve gap, described movable valve gap right side is connected with fixed stop (8) by the spring (6) that is enclosed within on the spool (13), is fixedly equipped with a back-up ring (3) on the spool (13) in movable valve gap left side.

2. the air operated reversing valve of a kind of pre-gas-filled type according to claim 1, it is characterized in that, described photoelectricity signal transmitter (2) is made up of three optoelectronic switches, corresponds respectively to initial sender, timing sender, stops sender, and the optoelectronic switch that adopts the neutral position is as the timing sender.