CN1036735C - Titration apparatus - Google Patents

Abstract

The present invention belongs to a chemical analysis liquid measuring instrument used for feeding and titrating. The present invention is characterized in that a ball 9 is arranged between the pistons 2 and 13 of syringes 1 and 14, the syringes 1 and 14 are oppositely fixed on one shaft, the syringe 14 is communicated with a pressure source 16, and the syringe 1 is respectively communicated with a liquid discharging tube 24 and a liquid bottle 19 with a pressure source 17 through a tee piston 23. The syringe 1 can replenish liquid from the liquid bottle 19 and discharge liquid from an air exhaust pipe 24 by controlling the tee piston 23 under the action of the pressure sources. The present invention not only can increase the liquid measuring speed, but also can increase the accuracy (precision +/-0.1%, and reproducibility +/-0.02%).

Description

Titration apparatus

The invention belongs to chemical analysis liquid measure device, is a kind of apparatus that is used for liquid feeding and titration.

Liquid feeding and titration are operations the most basic in the chemical analysis, and the analyst depends primarily on the levels of precision of its liquid measuring device usually with the analysis precision of its sample of volumetric glass metering liquid.Indicate that all the A level product capacity permissible error of 10ml transfer pipet and buret is ± 0.2% in " the volumetric glass measurement verification regulations JJG196-90 commonly used " of State Bureau of Technical Supervision's promulgation and the description of product of U.S. FISHER company.

Existing multiple semi-automatic charger on the domestic and international market, as U.S. LABINDUSTRIES company, company of Mitsui ﹠ Co., Ltd. (MRK), the charger that Shanghai refinement glass instrument factory and Shenyang science and education instrument plant etc. produce is syringe connection two retaining valves, portable pistons and is used as power.This liquid feeding tolerance can improve liquid feeding speed, but because the seepage and the hand-power inequality of retaining valve easily causes than mistake, and common accurate is ± 1%, and reappearance is ± 0.1%, still can not replace volumetric glass such as transfer pipet to carry out accurate liquid feeding.

The digital buret of titration systems such as the ZD-3 type that the titrator that U.S. FISHER company produces, titrimetry instrument and Shanghai thunder magnetic instrument plant produce, ZDJ-4 type autotitrator, its structure all adopts syringe piston to be fixed on stepper motor driven screw mandrel one end, measure titrant by the pulse signal that counter is accepted and stepper motor is synchronous, be restricted often because of there is certain error in the mechanical room in the mechanical transfer, and owing to involving great expense, using.

The objective of the invention is to design a kind of liquid feeding volume and set up rapidly, titration dosage numeral shows, practicality easy and simple to handle, and the capacity precision surpasses the liquid-volume measurement apparatus of A level transfer pipet, buret accuracy standard.

The present invention is mainly by two piston/cylinders 1 and 14, two syringe pistons 2 and 13, one groups of amount posts 10 and 11, adjusting screw 12, ball 9, stop,threeway 23,20, two pressure sources 16 of liquid bottle 19 and bottle stopper and 17, one groups of conduits 15,18,21,22 and 24 and composition such as length measurement system.Length measurement system is again mainly by joining part 3, digital indicator 4, data-out port 5, zero setting button 6, switching button 7 and blade 8 compositions (as shown in drawings).

Two piston/cylinders 1 are relative up and down coaxial fixing with 14, corresponding 1 and 14 is respectively the syringe piston 2 and 13 that moves up and down freedom, good seal, be flexible connection between the piston 2 and 13, on its connecting shaft, be provided with ball 9, can make up the length amount post 10 and 11 of transposing mutually, and the adjusting screw 12 that screws in piston 13 outer ends.Syringe jacket 1 is communicated with stop,threeway 23 by conduit 22,23 two-way in addition, the one tunnel connects discharging tube 24, and one the tunnel connects conduit 21, in 21 liquid that pass in the gastight bottle stopper 20 insertion bottles 19 of tight plug, there is a conduit 18 to pass bottle stopper 20 on the liquid level in the bottle and is communicated with pressure source 17.Piston/cylinder 14 is communicated with pressure source 16 by conduit 15.The outer end of syringe piston 2 links by connection part 3 and the device for digit-displaying that can slide on blade 8, parallel and the end of 2 in blade 8 and piston is fixed, device for digit-displaying 4 can be with piston 2 same moved further, and device for digit-displaying 4 is provided with data-out port 5, zero setting button 6 and data-switching button 7.

The principle of work of this device is that the pressure of pressure source 16 revolves stop,threeway 23 greater than airborne air pressure, conduit 22 is communicated with discharging tube 24, under the effect of pressure source 16 pressure, promote piston 13 and 2 and move upward, discharging tube 24 is quantitatively discharged the liquid in the overcoat 1.The pressure of pressure source 17 revolves stop,threeway 23 again greater than pressure source 16, and conduit 21 is communicated with 22, and under the effect of pressure source 17 pressure, the liquid in the bottle 19 promotes piston 2 and 13 and moves downward, liquid make-up in the overcoat 1.Piston 2 and 13 axis often do not overlap, and have relative radial displacement during piston up-down, establish a ball 9 between the two-piston outer face, can eliminate the resistance that produces because of radial displacement relatively.

When this device was used for liquid feeding, liquid volume added depended on the stroke of piston 2.During the overcoat relative fixed, the stroke of piston 2 depends on the axially spaced-apart distance of piston 2 and piston 13 again.On the connecting shaft between the two-piston, the amount of being provided with post and adjusting screw by the amount post or the rotation adjusting screw of transposing combination different length, can regulate the spacing distance of two-piston, thereby liquid volume added are set up in control.

When this device is used for titration, by swivel tee piston 23, the replenishing of may command titrant, discharging and drainage rate.The discharge capacity of titrant is directly proportional with the displacement of piston 2, survey long device for digit-displaying 4 on blade 8 with piston 2 same moved further, can show the displacement of piston 2.Be decided to be zero-bit as the full liquid piston position with cylinder body 1, the discharge capacity of titrant can directly be read on digital indicator 4, and each liquid make-up, and piston 2 is got back to zero-bit, the display digit self-zeroing.

According to the principle of the invention, will measure the combination mutually in the use of post group, adjusting screw and length measurement system, can obtain several different performances, introduce every kind of performance below and use operation.

(1) digital display titration

The device for digit-displaying numeral shows titration dosage, self-zeroing after the fluid infusion.

During manual operation, revolve stop,threeway 23 connecting tubes 21 and 22, syringe replenishes titrant, and piston 2 and 13 moves down, and the following top that piston 13 moves to cylinder body 14 stops, and promptly mends full liquid, makes device for digit-displaying show zero by zero setting button 6.Revolve stop,threeway 23 connecting tubes 22 and discharging tube 24 again, discharging titrant is by stop,threeway 23 control drainage rate.When arriving titration end-point, device for digit-displaying directly shows amount of piston displacement.As connect conversion button 7, can convert the displacement that discharges titrant to volume and show according to the parameter that has deposited in.Revolve the stop,threeway fluid infusion again, mending full back device for digit-displaying can self-zeroing.

When operating automatically, the solenoid valve of can on discharging tube 24, connecting, with the discharging of control titrant, also can be with the titrant displacement data by the 5 input microprocessor control systems of the data-out port on the device for digit-displaying, the automatic titration that realizes setting in advance terminal point or determine terminal point automatically.

(2) the adjustable liquid feeding of level is arranged

By changing and the combined amount post, can set up out multistage liquid volume added fast.

Two piston/cylinders are coaxial relatively fixedly the time, and liquid volume added depends on the spacing of two-piston, and adjusting screw can be set up the nominal total volume of liquid feeding, and plug adds the amount post of different length between two-piston, can obtain different liquid volume addeds.The length of amount post is long more, and stroke of piston is short more, and liquid volume added is also just more little.Correlation according to liquid volume added and stroke.Precision is made the amount post of several different lengths, measures the post stack combinations with these several, can obtain a plurality of liquid volume addeds.For example the stroke value of 10%, 20% and 30% 3 capacity correspondence of nominal total volume is made the amount post of three kinds of length, these three amount column combinations can access seven grades of liquid volume addeds, and they are respectively 40%, 50%, 60%, 70%, 80%, 90% and 100% of nominal total volumies.

(3) stepless adjustable liquid feeding

In total liquid volume added scope, go out needed any liquid volume added with the adjusting screw scalable.

The overcoat of two syringes is coaxial relatively fixing, adjusts the length that screw exposes in piston 13 outer ends by rotation adjusting screw 12, to change the spacing of piston 2 and 13.Monitor the accent amount with device for digit-displaying, can access desired any liquid volume added.

Regulating step: revolve stop,threeway 23 connecting tubes 22 and 24, piston 2 moves to that the top stops on the cylinder body 1, by zero setting button 6, and display zero setting.Revolve 23 connecting tubes 21 and 22 again, the beginning fluid infusion, piston 13 moves downward to overcoat 14 tops and stops.Rotation adjusting screw 12, the amount infused that device for digit-displaying is shown reaches desired liquid volume added, holding screw, setting finishes.

This device replaces volumetric glass not only can improve the speed of liquid meter, and can improve precision (accuracy ± 0.1%, reappearance ± 0.02%), surpasses the accuracy standard of A level transfer pipet, buret.Thereby improve the chemical analysis especially precision and the efficient of capacity.

Claims (4)

1, a kind ofly is used for chemico-analytic titration apparatus, forms, it is characterized in that two piston/cylinders 1 are relative with 14 coaxial fixing, be provided with a ball 9 between the piston 2 and 13 by piston, piston/cylinder, pressure source, liquid bottles, conduit and length measurement system.

2,, it is characterized in that end at piston 2 has can be on blade 8 a movable device for digit-displaying according to the described titration apparatus of claim 1.

3,, it is characterized in that being provided with a coaxial adjusting screw 12 at the end of piston 13 according to the described titration apparatus of claim 1.

4,, it is characterized in that between piston 2 and 13, being provided with the cylinder of one group of interchangeable combination of different length according to the described titration apparatus of claim 1.