CN1243205A - Liquid flow reverser and method for determining reversing error - Google Patents

Abstract

The present invention relates to a fluid-flow reverser and reversing error determining method. It is characterized by that its nozzle is equipped with a mechanism for changing nozzle area to make fluid flow speed constant when the fluid flow is reversed. The reversing hopper is a "V"-type dispersion-wedge reversing hopper, and utilizes the dispersion-wedge plunge flow to eliminate impact effect interference. Said invention also possesses another feature, i. e. it can make the flow correction equipment operate under the constant flow, and utilizes long and short time correction to calculate the reversing random uncertainty. Said method can be suitable for weight method and volume method, and its step key point is suitable for dynamic method to obtain the dynamic error.

Description

Liquid flow reverser and reversing error are determined method

The present invention relates to a kind of liquid flow reverser and error thereof that is used for fluid flow standard set-up or the quick switching of other need flow direction and determine method.

Switch flow direction at present following three kinds of structures arranged:

1, piston type commutation: with piston move left and right position change flow direction.Its shortcoming is that commutation causes the liquid rheologyization, and instability needs diverter switch, solenoid valve owing to change piston position, causes reversing error bigger.

2, the device that is referred to as " crotch " the realization fluid reversing that moves back and forth, because " crotch " device is bigger, required thrust is just big, be difficult for like this promoting fast, therefore make " crotch " forward-reverse time long, both times can not be in full accord, because both time absolute values are big, therefore its time difference is also bigger, therefore can bring systematic error and random error to the flow standard device.

3, " crotch " is motionless and lead the reversing arrangement of mouth left rotation and right rotation several angle.94238901.8 patent is exactly this commutator, its shortcoming is non-constant through leading the mouth flow rate of liquid, and " crotch " had shock effect.Thereby prior art when switching the commutation of liquid stream all with liquid stream " liquid flow impact " phenomenon to commutator, the precision of method of the reversing error of being tried to achieve by above-mentioned reversing arrangement is relatively poor.

The object of the invention provides a kind of liquid flow reverser and the reversing error that can eliminate " liquid flow impact " when switching the commutation of liquid stream and determines method.

For this reason, technological scheme of the present invention is finished like this: liquid flow reverser is made up of framework, nozzle, reversing hopper, be characterized in that nozzle is equipped with one and becomes nozzle area mechanism, it respectively is equipped with a baffle plate about by jet expansion, and the adjusting screw rod that is used for the controllable register move left and right is formed, be used to regulate the nozzle exit area so that when commutation flow rate of liquid constant.Reversing hopper is one " crotch " formula dispersion-wedge reversing hopper, it comprises funnel, slide block and guide rail, funnel is fixedlyed connected with a slide block, the slide block lower end places on the guide rail, the slide block center is equipped with one with the dispersion-wedge of the formula of splitting by streamer, and the wedge upper end is near nozzle flapper, and slide block is taken turns the tooth bar transmission that reaches with its engagement by motor, halogen, both sides at framework top nozzle center line respectively are equipped with the commutation collision block, commutate to switch about fluid flow.

Reversing error of the present invention is determined method step:

1, make traffic alignment equipment commutation inlet flow rate of liquid constant;

2, to grow alignment time calibration (can be 40 seconds or 10 seconds), record alignment time t ₀And mass M ₀(or volume V ₀) flow when calculating this (flow rate) q ₀(or Q ₀);

3, make traffic alignment with short time t1:

(1) alignment time short time t1 should satisfy two conditions

1. less than the long alignment time, be 20% of the long alignment time;

2. t1 absolute value＜2 second

(2) lack alignment time trickle quality (or volume) and use bucket metering in a small amount, its Measurement Uncertainty multiply by this ladle capacity in a small amount less than total relative uncertainty δ q of the calibration that (or being approximately equal to) desires to reach;

4, the utilization following formula calculates this time reversing error mks:

mks＝m1-t1q ₀

Can get n statistics mks by n (n can be n 〉=10) short time calibration ... mksn.

5, calculating mean value $\stackrel{-}{m}\mathrm{ks}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{mksi}}{n}$

6, calculate the commutation random uncertainty ${\mathrm{\ϵmnke}}^{*}=\mathrm{t\α}\·\sqrt{\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{(\mathrm{mksi}-\mathrm{mks})}^2}{n-1}}$ The confidence limit that t α distributes for the student third constellations in the formula, relevant with fiducial probability and frequency n,

7, calculate mass flow rate by following formula: $q=\frac{m-\stackrel{-}{m}\mathrm{ks}}{t}$

Mks is used for the correction that formal traffic alignment records mass flow rate,

ε mnke ^*Be used for calculated flow rate uncertainty or flow uncertainty as requested and determine the size of mass flow rate (or volume) conversely, promptly $m=\frac{\mathrm{\ϵmnk}{e}^{*}}{\sqrt{\mathrm{\δ}{q}^2-\mathrm{\δ}{t}^2-\mathrm{\δ}{s}^2}}$

Liquid flow reverser embodiment of the present invention is described further in conjunction with the accompanying drawings.

Fig. 1 is the liquid flow reverser structural representation.By shown in Figure 1, it is made up of framework, nozzle, reversing hopper, nozzle is equipped with one and becomes nozzle area mechanism, it respectively is equipped with a baffle plate 3 about by nozzle 1 outlet, and the adjusting screw rod 2 that is used for controllable register 3 move left and right forms, become that nozzle area mechanism regulates the nozzle exit area so that during commutation flow rate of liquid constant.Reversing hopper is one " crotch " formula dispersion-wedge reversing hopper, it comprises funnel 6, slide block 7 and guide rail 9 compositions, funnel 6 is fixedlyed connected with a slide block 7, the slide block lower end places on the guide rail 9, the slide block center is equipped with one with the dispersion-wedge 4 of the formula of splitting by streamer, and the wedge upper end is near nozzle flapper 3, and slide block reaches and its engage teeth 8 transmissions by motor 15, gear 14, each displacement changes the wedge direction to collision block 5 on the framework 13 of nozzle 1 center line both sides.When the commutation wedge is back and forth by the streamer center when commutating to switch fluid flow, begins and finish as timing.12 is liquid storage tank among Fig. 1.

The commutation working procedure is operated following explanation:

1, long-pending by becoming nozzle area screw mechanism adjusting jet area:

2, take into account by-pass cock by flow in the test stand pipeline, transfer to desire calibrated fluxes, at this moment reversing hopper is at left side limit position, and is represented as dot and dash line among Fig. 1.

3, starting reversing motor 15 travels at the uniform speed, driven gear 14 reaches the tooth bar 8 with its engagement, slide block 7 is slided on guide rail 9, drive reversing hopper to the right at the uniform velocity by the jet expansion streamer, when wedge 4 passed through the streamer center, time keeping instrument was connected timing, leaves streamer fully at dispersion-wedge, when promptly running into collision block 5, disconnect motor.

4, after liquid flows out certain hour, oppositely connect motor, make reversing hopper, when dispersion-wedge passes through the streamer center, disconnect timing, and when dispersion-wedge leaves streamer fully, promptly run into left side collision block 5 and send signal disconnection motor left by streamer.

Repetitive routine 1-4 when 5, doing a same traffic calibration.

The dispersion-wedge forward is to the timing of streamer center and be backwards to the streamer center and disconnect timing, be correction time during this period of time, and fluid flows in during this period of time in barrels 10, by load cell 11 claim weight, then

If the short time calibration then is to make dispersion-wedge then alignment time shortening back and forth fast, utilize the reversing error described in this commutator and the scheme to determine that method just can get mass flow rate or volume flow, tries to achieve the commutation random uncertainty.

Advantage of the present invention is to utilize the plunge flow of dispersion-wedge can eliminate the shadow of shock effect Ring, the reversing error that proposes determines that the method precision is high.

Claims (2)

1, a kind of liquid flow reverser, it is made up of framework, nozzle, reversing hopper, it is characterized in that: nozzle is equipped with one and becomes its adjusting screw rod (2) of respectively being equipped with a baffle plate (3) and controllable register (3) move left and right about by nozzle (1) outlet port of nozzle area mechanism and form, become nozzle area mechanism and regulate the nozzle exit area, so that flow rate of liquid is constant during commutation; Reversing hopper is one " crotch " formula dispersion-wedge reversing hopper, it comprises funnel (6), slide block (7), reaches guide rail (9), funnel (6) is fixedlyed connected with a slide block (7), the slide block lower end places on the guide rail (9), slide block (7) center is equipped with one with the dispersion-wedge (4) of the formula of splitting by streamer, wedge upper end near nozzle flapper (3), slide block (7) by motor (15), gear (14) and with tooth bar (8) transmission of its engagement, on the framework (13) of nozzle (1) center line both sides, respectively be equipped with commutation collision block (5), commutate to switch about fluid flow.

2, a kind of reversing error is determined method, and its step is as follows:

(1) make traffic alignment equipment commutation inlet flow rate of liquid constant;

(2) to grow alignment time calibration (can be 40 seconds or 10 seconds), record alignment time t ₀And mass M ₀(or volume V ₀) flow when calculating this (flow rate) q ₀(or Q ₀);

(3) make traffic alignment with short time t1:

1. alignment time short time t1 satisfies two conditions:

A, less than the long alignment time, be 20% of the long alignment time;

B, t1 absolute value＜2 second.

2. short alignment time trickle quality (or volume) is used bucket metering in a small amount, and its Measurement Uncertainty multiply by this ladle capacity in a small amount less than total relative uncertainty δ q of the calibration that (or being approximately equal to) desires to reach;

(4) the utilization following formula calculates this time reversing error mks:

Mks=m1-t ₁g ₀Can get n statistics, mks by n (n can be 〉=10) short time calibration ... mksn

(5) calculating mean value: $\stackrel{-}{m}\mathrm{ks}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{mksi}}{n}$

(6) calculate the commutation random uncertainty $\mathrm{\ϵmnke}=\mathrm{t\α}\·\sqrt{\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{(\mathrm{mksi}-\stackrel{-}{m}\mathrm{ks})}^2}{n-1}}$ The confidence limit that t α distributes for the student third constellations in the formula, relevant with fiducial probability and frequency n.

(7) calculate mass flow rate by following formula: $q=\frac{m-\stackrel{-}{m}\mathrm{ks}}{t}$

Mks is used for the correction that formal traffic alignment records mass flow rate.

ε mnke ^*Be used for calculated flow rate uncertainty or flow uncertainty as requested and determine the size of mass flow rate (or volume) conversely, promptly $m=\frac{\mathrm{\ϵmnk}{e}^{*}}{\sqrt{\mathrm{\δ}{q}^2-{\mathrm{\δt}}^2-{\mathrm{\δs}}^2}}$

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