CN202330216U

CN202330216U - Automatic timing device of capillary tube viscometers

Info

Publication number: CN202330216U
Application number: CN2011204547828U
Authority: CN
Inventors: 张华勇; 李天铎; 邱书波
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2011-11-16
Filing date: 2011-11-16
Publication date: 2012-07-11
Anticipated expiration: 2021-11-16

Abstract

An automatic timing device for a capillary viscometer belongs to the technical field of automatic timing for a capillary viscometer. It includes platinum wire electrodes and single-chip microcomputers, etc., and is characterized in that one end of platinum wire electrodes A and B are respectively fixed at timing lines a and b in the detection tube, and the other ends of platinum wire electrodes A and B are respectively connected to two bridge arm resistors, The bridge arm resistance is connected to the positive pole of the DC power supply; one end of the platinum wire electrode C is fixed below the timing line b in the detection tube, and the other end is connected to the negative pole of the bridge; the voltage output signals of the two bridges are amplified by the comparison amplifier and connected to the two A level shifting circuit, the two level shifting circuits are respectively connected to the interface of the single-chip microcomputer; the single-chip microcomputer is connected with the digital display. The utility model has the advantages that the detection head is fixed on the pipe wall, which prevents the error caused by the movement of the probe caused by the collision vibration. Liquids of various colors or transparency can be measured. The temperature resistance of platinum wire electrodes is greater than that of optical components such as optical fibers, and can detect high-temperature liquids. The production is simple and the cost is low.

Description

A kind of automatic timing unit of capillary viscosimeter

Technical field

The utility model relates to a kind of automatic timing unit of capillary viscosimeter, belongs to the self-clocking technical field of capillary viscosimeter.

Background technology

Capillary viscosimeter is an important instrument of measuring related characteristics parameters such as Viscosity of Polymer Solutions, molecular weight, the degree of branching.In the viscosity measurement of traditional Polymer Solution crow formula, employing be visual inspection and the manual method of manual time-keeping, waste time and energy, precision is not high.In order to measure the limiting viscosity of superpolymer more fast, more accurately, the U.S., Germany and Japan and other countries are successively developed various automatic capillary viscosity testing tool.All produce series capillary viscosity analyzer automatically like German SCHOTT company and U.S. CANNON company; Domestic Shanghai and Nanjing also have company to produce automatic viscosity tester, but these automatic viscosity apparatus all carry out Level Detection through fibre-optical probe, owing to excessively pursue the versatility of automaticity and instrument; Make its design go up and have some defectives; Be unfavorable for the raising of accuracy of instrument, separate with viscosity meter that the different viscosities meter can be replaced etc. at any time like detection probe.Because there is error in the position that picks and places, adds collision and the pollution of loading or unloading operation to detection probe or optical fiber head, introduces error unavoidably at every turn; In addition, optical fiber detects and is inappropriate for adopting dark liquid, and the heatproof degree of normal optical electric device is lower, when carrying out the high temperature viscosity test, also can't use.

Summary of the invention

Be defective and the deficiency that overcomes prior art, the utility model provides a kind of automatic timing unit and clocking method of capillary viscosimeter.

The technical scheme of the utility model is following:

A kind of automatic timing unit of capillary viscosimeter; Comprise three platinum electrode A, B and C, two electric bridges, two comparison amplifiers, two level shifting circuits, single-chip microcomputer, display driver chip and digital indicators; It is characterized in that platinum electrode A one end is fixed on the capillary viscosimeter detector tube clocking internal line a; Platinum electrode B one end is fixed on the capillary viscosimeter detector tube clocking internal line b, the other end of two platinum electrode A, B respectively with first and second electric bridge in arm resistance be connected; Platinum electrode C one end is fixed on capillary viscosimeter detector tube clocking internal line b and sentences down, and it is extreme that its other end is connected to the power-that inserts two electric bridges, thereby feasible the serial connection by platinum electrode A or B, platinum electrode C and fluid to be measured constitutes testing resistance; " bridge " Zhi Luduan of first electric bridge and second electric bridge receives the input end in first and second comparison amplifier respectively; The output terminal of first and second comparison amplifier is received the input end of first and second level shifting circuit respectively, and the output terminal of two level shifting circuits is connected respectively on the interface of single-chip microcomputer; Single-chip microcomputer is connected with display driver chip through its I/O mouth, and display driver chip is connected with digital indicator;

Described level shifting circuit connects a not circuit at the back by a current-limiting resistance and constitutes.

Described three platinum electrode A, B and C direct sintering in the glass tube walls of capillary viscosimeter detector tube so that its fix; Manage outer platinum electrode part and be fixed on the glass tube outer wall with the glass tube encapsulation, the glass tube sealing part is equipped with binding post A ' B ' C ' and is connected with platinum electrode A, B and C respectively.

A kind of method of utilizing above-mentioned time set to carry out timing adopts the Interrupt Process mode to carry out timing, comprises display process process and Interrupt Process process (being the timing processing procedure), and wherein the display process process steps is following:

1) beginning;

2) timer initialization;

3) put Abort Timer;

4) put outer the interruption;

5) put millisecond counter;

6) judge whether to arrive refresh time,, change step 7) over to if refresh time arrives, if the time less than, return repeating step 6);

7) viewing area data processing, demonstration refreshes;

8) judge that whether A electrode and B electrode connect simultaneously, if when connecting simultaneously then change step 9) over to, if connect simultaneously then directly return step 6);

9) timing display resets, and returns step 6) then.

In carrying out the display process process, when the A electrode breaks off, produce and interrupt, carry out Interrupt Process process (promptly carrying out the timing processing procedure), step is following:

1. Interrupt Process begins;

2. judge whether the A electrode breaks off,, change step over to 3.,, return repeating step 2. if do not break off if break off;

3. reset timer;

4. judge whether that the A electrode breaks off and the B electrode is connected, if then change step over to 5., if not then returning repeating step 4.;

5. timing adds up;

6. judge that whether A electrode and B electrode break off simultaneously, if break off simultaneously then change next step over to, if break off simultaneously then return step 5.;

7. timing stops;

8. return the breakpoint place.

The principle of work of the utility model is following: when the detector tube of capillary viscosimeter is measured; When the fluid to be measured liquid level is positioned on the timing line a position; Because making, the electric conductivity of the liquid of surveying forms a closed-loop path of forming by the arm resistance among platinum electrode A, the electric bridge A, direct supply and platinum electrode C; Another closed-loop path is made up of the arm resistance among platinum electrode B, the electric bridge B, direct supply and platinum electrode C; After the signal of " bridge " Zhi Luduan in two electric bridges amplifies through operational amplifier, introduce level shifting circuit and carry out again signal being sent in the single-chip microcomputer after digital signal conversion and signal amplify; When dropping to, the fluid to be measured liquid level is positioned at timing line a when following; (disconnection of A electrode) broken off in first closed-loop path; Electric bridge under its off-state output signal amplify through first via comparison amplifier and the level shifting circuit conversion after signal is sent in the single-chip microcomputer, the moment that the end points of platinum electrode A leaves liquid level at timing line a place picks up counting constantly; When dropping to, the fluid to be measured liquid level is positioned at timing line b when following; The two-way closed-loop path is broken off; The output signal of two electric bridges is sent into signal in the single-chip microcomputer after changing through amplification of two-way comparison amplifier and level shifting circuit; The end points of platinum electrode B leaves the moment end of timing constantly of liquid level at timing line b place, through after the single-chip microcomputer timing timing result being delivered to digital indicator with the demonstration time.When fluid to be measured is drawn onto timing line a when above once more, the two-way closed-loop path is connected, and timing display resets, when preparing next time meter.

The beneficial effect of the utility model:

1. detection probe is fixed on the viscosity meter tube wall, prevents to collide and vibrates the detecting head that causes and move the error that causes.

2. can detect the liquid of shades of colour or transparency.

3. the heatproof degree of platinum electrode can detect the liquid of higher temperature much larger than photovalves such as optical fiber.

4. make simply, cost is lower.

Description of drawings

Fig. 1 is a capillary viscosimeter detector tube position synoptic diagram, and Fig. 2 is the fixed position synoptic diagram of the utility model capillary viscosimeter detector tube position three platinum electrode A, B and C.

Wherein: 1. ball steeps, 2. kapillary, 3. timing line a, 4. timing line b.

Fig. 3 is the utility model automatic timing unit structural representation.

Wherein: 5. electric bridge A, 6. electric bridge B, 7. level shifting circuit A, 8. level shifting circuit B, 9. single-chip microcomputer, 10. display driver chip, 11. direct supplys, 12. comparison amplifier A, 13. comparison amplifier B, 14. digital indicators.

Fig. 4 is the circuit diagram of electric bridge, comparison amplifier and level shifting circuit in the utility model device.

Wherein: 15. protective resistances, 16. protective resistances, 17. comparison amplifiers, 18. current-limiting resistances, 19. not circuits; The MN of electric bridge end is galvanometer G branch road among the figure, i.e. " bridge " Zhi Luduan, and the PQ end props up terminal for power supply E, and Ra is an arm resistance, and Rb, Rx are measuring resistance.

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described further, but is not limited thereto.

Embodiment:

The utility model embodiment is shown in Fig. 1-4; Comprise three platinum electrode A, B and C, two electric bridges 5 and 6, two comparison amplifiers 7,8, two level shifting circuits 12,13, single-chip microcomputer 9, display driver chip 10 and digital indicators 14; It is characterized in that platinum electrode A one end is fixed on the capillary viscosimeter detector tube clocking internal line a 3; Platinum electrode B one end is fixed on the capillary viscosimeter detector tube clocking internal line b4, the other end of two platinum electrode A, B respectively with first and second electric bridge 5 and 6 in arm resistance Ra be connected; Platinum electrode C one end is fixed on below the capillary viscosimeter detector tube clocking internal line b4 place, and it is extreme that its other end is connected to the power-that inserts two electric bridges 5 and 6, thereby feasible the serial connection by platinum electrode A or B, platinum electrode C and fluid to be measured constitutes testing resistance; " bridge " branch road M N end of first electric bridge and second electric bridge is received the input end in first and second comparison amplifier 7 and 8 through protective resistance 15,16 respectively; First and second comparison amplifier 7 and 8 output terminal are received the input end of first and second level shifting circuit 12 and 13 respectively, and the output terminal of two level shifting circuits 12,13 is connected respectively on the interface of single-chip microcomputer 9; Single-chip microcomputer 9 is connected with display driver chip 10 through its I/O mouth, and display driver chip 10 is connected with digital indicator 14;

Described

level shifting circuit

12 or 13 connects a not circuit 19 by a current-limiting resistance 18 back and constitutes.

The used single-chip microcomputer of the utility model embodiment is the PIC16F877 single-chip microcomputer.

Claims

1. An automatic timing device of a capillary viscometer, comprising three platinum wire electrodes A, B and C, two electric bridges, two comparative amplifiers, two level conversion circuits, a single-chip microcomputer, a display driver chip and a digital display, its It is characterized in that one end of the platinum wire electrode A is fixed on the timing line a in the detection tube of the capillary viscometer, one end of the platinum wire electrode B is fixed on the timing line b in the detection tube of the capillary viscometer, and the other ends of the two platinum wire electrodes A and B are respectively connected to the first One end and the bridge arm resistance in the second electric bridge are connected; one end of the platinum wire electrode C is fixed below the timing line b in the detection tube of the capillary viscometer, and the other end is connected to the negative end of the power supply connected to the two electric bridges, so that by Platinum wire electrode A or B, platinum wire electrode C and the measured liquid are connected in series to form the resistance to be measured; the "bridge" branch ends of the first electric bridge and the second electric bridge are respectively connected to the first and second comparator The input terminals in the amplifier, the output terminals of the first and second comparison amplifiers are respectively connected to the input terminals of the first and second level conversion circuits, and the output terminals of the two level conversion circuits are respectively connected to the interface of the single-chip microcomputer; The single-chip microcomputer is connected with the display driver chip through its I/O port, and the display driver chip is connected with the digital display; the level conversion circuit is composed of a current limiting resistor connected with a NOT gate circuit.

2. the automatic timing device of a kind of capillary viscometer as claimed in claim 1 is characterized in that described three platinum wire electrodes A, B and C are directly sintered in the glass tube wall of capillary viscometer detection tube so that it Fixed, the platinum wire electrode part outside the tube is sealed and fixed on the outer wall of the glass tube with a glass tube, and the sealing part of the glass tube is equipped with binding posts A'B'C' to connect with the platinum wire electrodes A, B and C respectively.