CN201653856U - Liquid surface tension measuring device - Google Patents

Abstract

A liquid surface tension measuring device comprises a base (7) and a bracket (6); a vessel (10) for accommodating liquid to be measured is arranged in the middle of the top surface of the base (7); a scale pole (9) and the bracket (6) perpendicular to the top surface of the base are arranged on the left and the right sides of the vessel respectively; a height display (12), a holding contact pin arm (13) and an adjusting screw (14) are arranged on the scale pole (9); an elevation scale is formed on the scale pole (9); the height display (12) is integrally connected with the holding contact pin arm; a vertically downward L-shaped contact pin (11) is clamped on a clamp at the free end of the holding contact pin arm (13); a slide block (3) with a tightening screw (4) is arranged on the bracket (6); a pipe clamping arm (2) is connected with the slide block integrally; a vertically downward capillary pipe (5) is clamped by a clamp (1) at the free end of the pipe clamping arm; and both the pipe clamping arm (2) and the holding contact pin arm (13) are mounted parallel to the top surface of the base (7). The utility model relates to the liquid surface tension measuring device, which can be extensively applied to teaching, scientific research and industrial and agricultural production, and have the advantages of low cost, stable and accurate measuring number values, convenient operation and easy mastery.

Description

The liquid surface tension detection instrument

Technical field

The utility model relates to the physical property of liquid analyzer of a kind of teaching, scientific research and industrial application, specifically is the liquid surface tension detection instrument.

Background technology

The liquid surface tension detection method pulls method, capillary tube technique, sessile drop method, liquid volumetric method and maximum bubble method etc., and the method that wherein pulls all need be used the high force transducer of accuracy requirement, cost height, fragile, and what influence was measured normally carries out.And sessile drop method, drop-volume method and maximum bubble method have instability, precision to owe desirable defective.CN2938074 has announced " a kind of Measurement of liquid surface tension coefficient instrument ", also be to adopt highly sensitive force transducer, mensuration Displaying Meter, restrictor to be formed by combining, the destruction of liquid level film when having avoided manual operation, the mensuration of survey tension force is closing to reality more, and realize the conversion of magnitude of voltage and power value automatically and directly show tension value, but this instrument cost height.

The utility model content

The technical problems to be solved in the utility model is to design a kind of liquid surface tension detection instrument that adopts capillary tube technique.

The technical scheme that solves the problems of the technologies described above is: this liquid surface tension detection instrument, include base and support, it is characterized in that there is the container of containing testing liquid at the base top surface middle part, the left and right sides of container has respectively perpendicular to the scale bar of base top surface and support, elevation indicator is arranged on the scale bar, hold contact pilotage arm and adjustable screw, reference mark is arranged on the scale bar, display with hold the contact pilotage arm and be connected as a single entity, hold clamping on the clip of free-end of contact pilotage arm vertically downward L shaped contact pilotage is arranged, there is band to tighten the sliding shoe of spiral on the support, clamp arm and sliding shoe link into an integrated entity, the clip of clamp arm free-end accompanies kapillary vertically downward, the clamp arm with hold all parallel installation of contact pilotage arm with base top surface.

Said container is the double walled water-bath type container that has water inlet pipe and rising pipe.

Said container is a monolayered vessel, and there are receptacle stand and spirit lamp in its below.

Be lined with flexible gasket in the clip of said clamp arm free-end.

The length of said kapillary and contact pilotage (11) is greater than container depth and clip (1) height sum, the diameter 0.1-0.3mm of L shaped contact pilotage, and the internal diameter of kapillary (5) is 0.7-1.1mm.

The beneficial effects of the utility model are the cheap of instrument itself, the numerical stability of mensuration and accurately, easy to operate, easy grasp.

Description of drawings

Accompanying drawing is the utility model structural representation.

Specific implementation method

The utility model is described in further detail below in conjunction with embodiment and with reference to accompanying drawing: introduce the principle and relevant calculating and the error correcting method that adopt capillary tube technique to measure surface tension of liquid earlier:

Kapillary is inserted in the infiltration liquid, and when just inserting, contact angle θ is an acute angle, and liquid level just forms concave surface.Because capillary effect makes liquid level rise.Surface tension size F and liquid level lifting height h have following relation:

Fcosθ＝ρghS (1)

ρ is a fluid density in the formula, and g is an acceleration of gravity, and s is the kapillary sectional area.

Again because surface tension F and surface tension coefficient α have following relation:

F＝2πrα (2)

(2) substitution (1) formula is got

$\mathrm{\&alpha;}=\frac{\mathrm{h\&rho;<figure-callout\; id="2"\; label="gr"\; filenames="HSA00000028919700011.png"\; state="\{\{state\}\}">gr</figure-callout>}}{2\cos \mathrm{\&theta;}}---\left(3\right)$

θ is relevant with the character of liquid and pipe wall material in the formula.

Should be pointed out that when measuring liquid level lifting height h, should be from liquid level concave surface minimum point amount to the outer flat liquid level of pipe, and more than the height, around concave surface, also have small amount of liquid at this, and concave surface in the pipe is considered as semisphere, the modified value of reply h increase r/3 promptly has

$\mathrm{\&alpha;}=\frac{1}{2\cos \mathrm{\&theta;}}\mathrm{\&rho;gr}(h+\frac{r}{3})=\frac{1}{4\cos \mathrm{\&theta;}}\mathrm{\&rho;gd}(h+\frac{d}{6})---\left(4\right)$

If do not consider the influence of temperature,, just can calculate the surface tension coefficient of liquid by formula (4) as long as accurately measure liquid-column height h and kapillary interior diameter d in the kapillary to fluid density.

For a certain liquid, surface tension coefficient is also relevant with the temperature of liquid, so the temperature that when experiment must recording liquid.

This liquid surface tension detection instrument, include base 7 and support 6, there is the container 10 of containing testing liquid at base 7 end faces middle part, the left and right sides of container has respectively perpendicular to the scale bar 9 of base top surface and support 6, elevation indicator 12 is arranged on the scale bar 9, hold contact pilotage arm 13 and adjustable screw 14, on the scale bar 9 reference mark is arranged, display 12 with hold the contact pilotage arm and be connected as a single entity, hold clamping on the clip of free-end of contact pilotage arm 13 vertically downward L shaped contact pilotage 11 is arranged, there is band to tighten the sliding shoe 3 of spiral 4 on the support 6, clamp arm 2 links into an integrated entity with sliding shoe, the clip (1) of clamp arm free-end accompanies kapillary 5 vertically downward, clamp arm 2 with hold contact pilotage arm 13 all with the parallel installation of base 7 end faces.

Said container 10 is for having the double walled water-bath type container of water inlet pipe and rising pipe.

Said container 10 is a monolayered vessel, and there are receptacle stand 8 and spirit lamp in its below.

Be lined with flexible gasket in the clip 1 of said clamp arm 2 free-ends.

The length of said kapillary 5 and contact pilotage (11) is greater than container depth and clip (1) sum highly, the diameter 0.1-0.3mm of L shaped contact pilotage, and the internal diameter of kapillary (5) is 0.7-1.1mm.

During mensuration, earlier kapillary, contact pilotage, container are cleaned by testing requirements, again testing liquid is injected container 10, and the temperature sensor of digital temperature meter is put into testing liquid recording liquid temperature.

Choose the kapillary 5 of even thickness and length capillaceous, internal diameter are carried out survey record.The kapillary of choosing is positioned in the potassium bichromate solution, carries out cleaning.The kapillary 5 that cleaning is good is fixed on the clip 1 and up-down adjustment sliding shoe 3, when kapillary 5 inserts under the liquid level of testing liquids 0.5-1.5cm place, tightens spiral 4 and locate.

Turn setting nut 14, contact pilotage 11 is slowly descended, examine when contact pilotage 11 lower horizontal and overlap with inverted image in the water, at this time, the reading of regulating display 12 makes zero.

Observe the position of liquid level in the kapillary, turn setting nut 14, the minimum point of concave meniscus in contact pilotage horizontal segment, the kapillary and their imaging in level crossing (among the figure mark) is overlapped, the reading of reading displayed device 12 at this time, this reading value is the height that liquid level rises in the kapillary.With this data recording.

When needing heating or constant temperature to measure, heat or water-bath is heated, make the testing liquid temperature constant relatively, during as 10 ℃ of every risings of temperature, repeat above step, measurement data is recorded in the form one by one at a certain temperature value with spirit lamp.To explosive flammable liquid, only heat with water-bath.

With numerical value of above-mentioned each record, the aforementioned correlation formula of substitution calculates the surface tension and the surface tension coefficient of fluid to be measured at last.

Claims (5)

1. liquid surface tension detection instrument, include base (7) and support (6), it is characterized in that there is the container (10) of containing testing liquid at base (7) end face middle part, the left and right sides of container has scale bar (9) and the support (6) perpendicular to base top surface respectively, elevation indicator (12) is arranged on the scale bar (9), hold contact pilotage arm (13) and adjustable screw (14), scale bar has reference mark on (9), display (12) with hold the contact pilotage arm and be connected as a single entity, hold clamping on the clip of free-end of contact pilotage arm (13) vertically downward L shaped contact pilotage (11) is arranged, there is band to tighten the sliding shoe (3) of spiral (4) on the support (6), clamp arm (2) links into an integrated entity with sliding shoe, the clip (1) of clamp arm free-end accompanies kapillary (5) vertically downward, clamp arm (2) with hold contact pilotage arm (13) all with the parallel installation of base (7) end face.

2. liquid surface tension detection instrument as claimed in claim 1 is characterized in that said container (10) is for having the double walled water-bath type container of water inlet pipe and rising pipe.

3. liquid surface tension detection instrument as claimed in claim 1 is characterized in that said container (10) is a monolayered vessel, and there are receptacle stand (8) and spirit lamp in its below.

4. liquid surface tension detection instrument as claimed in claim 1 is characterized in that being lined with flexible gasket in the clip (1) of said clamp arm (2) free-end.

5. liquid surface tension detection instrument as claimed in claim 1, the length that it is characterized in that said kapillary (5) and contact pilotage (11) is greater than container depth and clip (1) height sum, the diameter 0.1-0.3mm of L shaped contact pilotage, the internal diameter of kapillary (5) is 0.7-1.1mm.

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