CN202305095U

CN202305095U - High-accuracy automatic liquid manometer

Info

Publication number: CN202305095U
Application number: CN2011203904283U
Authority: CN
Inventors: 李向军; 郭显久; 邓长辉; 李松松
Original assignee: Dalian Ocean University
Current assignee: Dalian Ocean University
Priority date: 2011-10-14
Filing date: 2011-10-14
Publication date: 2012-07-04
Anticipated expiration: 2021-10-14

Abstract

A high-accuracy automatic liquid manometer comprises a U-shaped flexible pipe. Two ends of the U-shaped flexible pipe are respectively communicated with a reagent cup and a test tube. The high-accuracy automatic liquid manometer is characterized in that the reagent cup is placed on a longitudinal moving platform in threaded connection with a screw connected with a working end of a stepper motor, a floater is arranged in the test tube, a laser generator is arranged in a scope of an alpha angle slantly below the floater, value scope of the alpha is 20 degrees to 70 degrees, and the longitudinal axis of the test tube serves as a symmetry axis. A semiconductor position detection device is symmetrically arranged corresponding to the angle of the laser generator, a collecting mirror is arranged between the semiconductor position detection device and the test tube, the centre line of the collecting mirror coincides with that of the semiconductor position detection device which is connected with a computer through a differential motion amplification return circuit and an analog to digital (A/D) converter, the stepping motor is also controlled by the computer. The high-accuracy automatic liquid manometer has the advantages of being simple in structure, smart in design, capable of achieving high-accuracy measurement and automatically computing pressure value, high in accuracy and the like.

Description

High Precision Automatic liquid manometer

Technical field

The utility model relates to a kind of pressure gauge, particularly a kind of micro pressure measuring that can carry out, and can calculate automatically force value High Precision Automatic liquid manometer.

Background technology

Measuring accurately, automatically in fields such as fluid mechanics, surveying of slight pressure is very necessary.As adopt pitot tube to measure fluid measurement fields such as gentle breeze speed or low discharge.Liquid manometer is the human instrument that is used for the metering pressure value the earliest, it have simple in structure, easy to use, indicating value stable, good reproducibility, really measure characteristics such as accuracy height.Liquid manometer mainly comprises following several kinds of instrument types: benchmark microbarograph, compensate-type micropressure meter, tilting micromanometer, liquid manometer, cup U-tube manometer, U type pipe pressure meter etc., its actuating medium is mainly liquid mediums such as water, alcohol, oil or mercury.In the liquid manometer of this several types; No matter be to adopt compensation principle or utilize its inclination angle and area compares gaging pressure; The principle of work that its basic pressure measurement principle all is a U-tube manometer; Pressure and the tested pressure balanced principle of promptly utilizing the fluid column deadweight to produce through measuring liquid-column height, obtain by measuring pressure according to the fluid static pressure equation again.Liquid-column height is to represent that by metering scale (being generally mm unit) scale that reads on the scale through the tester obtains measurement result at present.Thereby very easily produce personal error.This pressure gauge can not be exported electric signal simultaneously, can't be applied in the middle of the automatic control system.Therefore need a kind of novel minute-pressure pressure gauge that can address the above problem now.

Summary of the invention

The utility model is in order to solve the above-mentioned deficiency of existing in prior technology, proposes a kind of simple in structurely, designs ingeniously, can realize high-acruracy survey, and can calculate the High Precision Automatic liquid manometer of force value automatically.

The technical solution of the utility model is: a kind of High Precision Automatic liquid manometer, comprise U type flexible pipe 1, and the two ends of U type flexible pipe 1 are communicated with reagent cup 2 and test tube 3 respectively; It is characterized in that: described reagent cup 2 is placed on the vertical shift platform 4; Vertical shift platform 4 is threaded with screw rod 5, and screw rod 5 links to each other with the working end of stepper motor 6, in test tube 3, is provided with float 7; Laser generator 8 is arranged in the oblique below α angular region of float 7; The span of α is: 20 degree are axis of symmetry to 70 degree with the longitudinal central axis line of test tube 3, are provided with semiconductor position detecting device 9 symmetrically with laser generator 8 angles; Between semiconductor position detecting device 9 and test tube 3, be provided with condenser 10; And the central lines of the center line of condenser 10 and semiconductor position detecting device 9, semiconductor position detecting device 9 is connected with computing machine with A/D converter through differential amplification loop, and stepper motor 6 is equally through computer control.

The utility model is compared with prior art, has following advantage:

The High Precision Automatic liquid manometer of the utility model embodiment, it is simple in structure, designs ingeniously, can realize the automatic measurements and calculations of slight pressure value, and result of calculation directly is presented on the display screen, has saved the labor capacity of survey crew; The more important thing is that it adopts computer automation control, can farthest eliminate traditional minute-pressure pressure gauge needs the people to measure the issuable error of the number of degrees for reading, and guarantees the accuracy and the authenticity of measurement result effectively.And this liquid manometer is with low cost, is suitable in engineering, scientific research, teaching field, applying.Therefore we can say that it has possessed multiple advantage, its market outlook are comparatively wide.

Description of drawings

Fig. 1 is the measuring principle figure of the utility model embodiment.

Fig. 2 is the structural representation of the utility model embodiment.

Fig. 3 is the circuit block diagram of the utility model embodiment.

Embodiment

Below with the embodiment of accompanying drawings the utility model.Like Fig. 1, shown in Figure 2:

The measuring principle of this liquid manometer at first is described:

When tested small pressure reduction Wei ⊿ P, shown in Fig. 1 (a), the liquid level in the test tube will be from the descend distance of x of null position, and the liquid level of reagent cup is with the distance of rising h, and liquid level difference H is like this:

H?=?x?+?h　(1)

The sectional area of supposing test tube and reagent cup is respectively a and A, then can obtain following formula:

h?=?a?x／A?　(2)

In order to simplify, capillary influence in test tube and the reagent cup is ignored, then can obtain according to the fluid static pressure equation:

⊿P=?ρgH　(3)

(ρ is the inner fluid density of liquid manometer, and g is an acceleration of gravity.）

Then, the distance (like Fig. 1 (b)) with reagent cup vertical-lift L makes the liquid level of test tube get back to original null position, and at this moment, even reagent cup is raised, the liquid level difference still keeps H constant (according to pascal's principle).Because the liquid in the pressure gauge is totally certain, under the situation of the volume-variation that causes in the distortion of ignoring connecting pipe, can obtain following formula according to Fig. 1:

L?=?C?+H－C?=?H　(4)

Can get thus, for the liquid level that makes test tube turns back to original null position, the displacement L of reagent cup equates with the liquid level difference H of pressure gauge two side pipes.Therefore, formula (3) can be rewritten as:

⊿P?=?ρgＬ

That is to say, if the displacement L of reagent cup can measure the liquid level of the test tube of sening as an envoy to and turn back to original null position the time, just could be through calculating the numerical value of small pressure power ⊿ P.

According to above-mentioned principle, be described in detail the course of work of the High Precision Automatic liquid manometer of the utility model embodiment:

Before not applying Dai Ce Ya Li ⊿ P; The laser that laser generator 8 sends is positioned at float 7 lower surfaces on test tube 3 liquid levels with the direction directive of α angle obliquely; Wherein the angular range of α is that 20 degree are to 70 degree (as shown in Figure 2); Point of irradiation place at float 7 can produce light at random, and the light at random here comprises after float 7 reflections, through the laser after unirefringence and the test tube 3 tube wall birefringences in the test tube 3; This part light at random is radiated at after through condenser 10 on the semiconductor position detecting device 9 (being called for short PSD), and this moment, the output valve of PSD was the null position of float 7;

In test tube 3, execute and add pressure power ⊿ P, to bottom offset, the contact point of laser and float 7 changes float 7 under the effect of pressure; The light at random that produces through float 7 also changes with the contact position of PSD behind optically focused thereupon, and PSD sends signal, transfers signals among the computing machine through differential amplification loop and A/D converter; Computer-controlled stepper motor 6 work, stepper motor 6 drives screw rod 5 and rotates, and corresponding length travel can take place in 4 on the vertical shift platform that is threaded on the screw rod 5; Because the liquid level in the reagent cup 2 promotes; Thereby also rising accordingly of the liquid level in the test tube 3, and it is mobile in the vertical to drive float 7, when float 7 returns to null position; PSD sends to computing machine with detected this signal, and computer-controlled stepper motor 6 quits work.

Angle of rotation α according to 6 each step of the stepper motor that is adopted; And screw rod 5 precision β (mm ∕ commentaries on classics), can confirm stepper motor 6 revolutions move a step the amount of movement of corresponding reagent cup 2, and calculate the displacement of reagent cup 2 in the vertical directions thus; Be L; Computing machine Gen Ju ⊿ P=ρ gL directly comes out the numerical evaluation of ⊿ P, and be presented on the display.

This High Precision Automatic liquid manometer can be realized automatic measurement, and it is accurate to have data, reduces advantages such as personal error.

Claims

1. High Precision Automatic liquid manometer; Comprise U type flexible pipe (1); The two ends of U type flexible pipe (1) are communicated with reagent cup (2) and test tube (3) respectively, it is characterized in that: described reagent cup (2) is placed on the vertical shift platform (4), and vertical shift platform (4) is threaded with screw rod (5); Screw rod (5) links to each other with the working end of stepper motor (6); In test tube (3), be provided with float (7), laser generator (8) is arranged in the oblique below α angular region of float (7), and the span of α is: 20 degree are to 70 degree; Longitudinal central axis line with test tube (3) is an axis of symmetry; Be provided with semiconductor position detecting device (9) symmetrically with laser generator (8) angle, between semiconductor position detecting device (9) and test tube (3), be provided with condenser (10), and the central lines of the center line of condenser (10) and semiconductor position detecting device (9); Semiconductor position detecting device (9) is connected with computing machine with A/D converter through differential amplification loop, and stepper motor (6) is equally through computer control.