CN104237066A - Method for measuring density of object - Google Patents

Abstract

The invention relates to a method for measuring the density of an object. In the method, the temperature of the object is set at a temperature required during density measurement, the mass of the object is measured, then, negative pressure is exerted on the environment where the object is placed for two times, the temperature, the volume and the pressure of gas during the two-time negative pressure exertion are measured, and the density value of the object is calculated through a formula. The method is scientific in principle, reasonable in process, simple in process and easy to operate; a result is high in precision; through actual application, an ideal effect is achieved.

Description

A kind of method measuring object density

Technical field

The present invention relates to a kind of measuring method, especially a kind of method measuring object density.

Background technology

In scientific research and engineering practice, density parameter is the important parameter in engineering calculation simulation process and scientific research experimentation.It is as important material property parameter, very large for physics and chemistry process influences such as heat transfer, mass transfer and MOMENTUM TRANSMISSION.In the measuring method of existing density parameter, the overwhelming majority utilizes liquid to discharge method, obtain the volume of testee, then testee is weighed, thus obtain the method for testee average density, as the patent that denomination of invention is " a kind of solid density measuring method ", publication number is CN101078677, but the method cannot measure the volume of the testee having water absorptivity or react with water, those objects that should not contact with water, as casting sand mold, some moisture absorption salt, also the method cannot be applied; Patent " portable density takes into account density measuring method ", publication number CN1084272, can the pressure of Quick Measurement liquid, but can only survey the density of liquid, cannot measure the density of solid, application has limitation equally; Patent " containing solid-liquid density measuring equipment and method ", publication number CN102207440A, the liquid can measuring complicated form especially solid-liquid the density of the potpourri deposited (containing solid-liquid), but the density of single solid cannot be measured, measuring accuracy depends on the feedback of liquid level sensor completely, if tested containing solid-liquid surface irregularity, will very large measuring error be there will be, clean after measurement device and also comparatively bother; Patent: " Powdery material density measurement device ", publication number CN2692657, can only measure the density of powdered substance; Patent: " differential pressure type density measurer " publication number CN2409514, the only density of measurable flow body, cannot measure the density of solid, and device is not with easy to clean later.

In sum, in existing technology, when testee is solid, adopt fluid-discharge therapy more, but cannot be suitable for the material of fluid-sensitive some; When testee mostly is fluid, powdered substance, regular shape can be constrained to it, calculate volume by liquid level sensor detecting, but cannot be measured by existing apparatus some erose solids.Meanwhile, in all technical schemes, only can provide the density value of the corresponding a certain temperature of testee, the density value of testee under different temperatures change cannot be provided.And in research practice, material is needed to carry out work sometimes under the condition of different temperatures, if the working temperature of some parts of aeromotor is between-50 ~ 1000 DEG C, therefore the work of material variable density at different temperatures to product or equipment is most important.In the face of the material of different materials, state, often do not have means to go to obtain the temperature variant densimetric curve of object, in existing technology, do not have ripe method to use for reference yet, thus cause carrying out engineering calculation.

Summary of the invention

The object of this invention is to provide a kind of measuring method measuring object density value at different temperatures, be intended to measure different objects density value at different temperatures, especially have erose solid or heterogeneous fluid, testee temperature range can between-50 ~ 1000 DEG C.By method proposed by the invention, the density value of testee in uniform temperature point or temperature range or the curve of density with temperature's change can be obtained.

Technical scheme of the present invention is, described measuring method comprises the following steps:

(1) by testee heating or the temperature that is cooled to needed for density measurement value;

(2) testee is placed in container, is also provided with the pressure transducer be connected with outside and vessel temperature sensor in container, described container is provided with piston, seal of vessel also can move up and down by piston;

(3) by testee together with closed container, be placed on poidometer, record the quality m of testee;

(4) tensile force f 1 that on the piston above closed container, applying one is outside, makes container be negative pressure state, after applying F1, the pressure P 1 in container should be made to meet: 0.5atm<P1<1atm;

(5) by pressure transducer and thermocouple sensor, measure the pressure P1, the temperature T1 that obtain air in closed container, after applying F1, the amount of movement of piston measures the volume V1 of tainer air;

(6) piston above closed container continues the tensile force f 2 that applying one is outside, and F2>F1, make container continue in negative pressure state;

(7) by pressure transducer and thermocouple sensor, measure the pressure P2, the temperature T2 that obtain air in closed container, after applying F2, the amount of movement of piston measures the volume V2 of tainer air;

(8) following formula is utilized:

$\mathrm{\&rho;}=\frac{m(P_1{T}_2-P_2{T}_1)}{(P_1{V}_1{T}_2-P_2{V}_2{T}_1)}$

Calculate the density of testee when temperature.

Principle of the present invention is the Clapyron Equation according to ideal gas, i.e. PV=nRT.For actual gas, every gas be not easily liquefied itself, and when temperature higher than room temperature, when pressure is not more than 1 atmospheric pressure, with ideal gas closely, can ideal gas be thought, go for Clapyron Equation.Gas in the present invention is air, is not easily liquefied; All adopt pulling force in the course of work, air ambient is negative pressure, therefore measures the result obtained, and can ensure required measuring accuracy.Meanwhile, thermopair can be set on testee, according to the different temperatures of object, just can be measured the density under different temperatures by above-mentioned steps, and then object densimetric curve at different temperatures can be generated.Principle of the invention science, process is reasonable, and technique is simple, and be easy to operation, result precision is high, through practical application, achieves desirable effect.

Accompanying drawing explanation

Fig. 1 is apparatus structure schematic diagram of the present invention.

Embodiment

As shown in the figure, a kind of method measuring object density, is characterized in that, described method comprises the following steps:

(1) testee 13 heated or be cooled to the temperature needed for density measure;

(2) testee is placed in container 5, is also provided with the pressure transducer 4 and vessel temperature sensor 8 that are connected with outside, described container 5 is provided with piston 7 in container 5, seal of vessel also can move up and down by piston 7;

(3) by testee 13 together with closed container 5, be placed on poidometer 1, record the quality m of testee 13;

(4) tensile force f 1 that on the piston 7 above closed container 5, applying one is outside, makes container 5 in negative pressure state, after applying F1, the pressure P 1 in container 5 should be made to meet: 0.5atm<P1<1atm;

(5) by pressure transducer 4 and vessel temperature sensor 8, measure the pressure P1, the temperature T1 that obtain air in closed container 5, after applying F1, the amount of movement of piston 7 measures the volume V1 of tainer air;

(6) piston 7 above closed container 5 continues the tensile force f 2 that applying one is outside, and F2>F1, make container 5 continue in negative pressure state;

(7) by pressure transducer 4 and vessel temperature sensor 8, measure the pressure P2, the temperature T2 that obtain air in closed container 5, after applying F2, the amount of movement of piston 7 measures the volume V2 of tainer air;

(8) following formula is utilized:

$\mathrm{\&rho;}=\frac{m(P_1{T}_2-P_2{T}_1)}{(P_1{V}_1{T}_2-P_2{V}_2{T}_1)}$

Calculate the density of testee when temperature.

Embodiment

Measure the density of PEPSET resin sand lump, its temperature is 28 DEG C, and concrete implementation step is as follows:

(1) testee is heated to the temperature 28 DEG C needed for density measure;

(2) testee is placed in container, is also provided with the pressure transducer be connected with outside and vessel temperature sensor in container, described container is provided with piston, seal of vessel also can move up and down by piston;

(3) by testee together with closed container, be placed on poidometer, record the quality m=0.5kg of testee;

(4) tensile force f 1 that on the piston above closed container, applying one is outside, makes container be negative pressure state, after applying F1, the pressure P 1 in container should be made to meet: 0.5atm<P1<1atm;

(5) by pressure transducer and thermocouple sensor, measure the pressure P1=0.8atm, the temperature T1=28 DEG C that obtain air in closed container, after applying F1, the amount of movement of piston measures the volume V1=5L of tainer air;

(6) piston above closed container continues the tensile force f 2 that applying one is outside, and F2>F1, make container continue in negative pressure state;

(7) by pressure transducer and thermocouple sensor, measure the pressure P2=0.7atm, the temperature T2=28 DEG C that obtain air in closed container, after applying F2, the amount of movement of piston measures the volume V2=5.67L of tainer air;

(8) following formula is utilized:

$\mathrm{\&rho;}=\frac{m(P_1{T}_2-P_2{T}_1)}{(P_1{V}_1{T}_2-P_2{V}_2{T}_1)}$

Calculate the density of testee when 28 DEG C of temperature:

ρ＝1.5×103kg/m3。

Claims (1)

1. measure a method for object density, it is characterized in that, described method comprises the following steps:

(1) testee (13) heated or be cooled to the temperature needed for density measure;

(2) testee is placed in container (5), the pressure transducer (4) and vessel temperature sensor (8) that are connected with outside is also provided with in container (5), described container (5) is provided with piston (7), and seal of vessel also can move up and down by piston (7);

(3) by testee (13) together with closed container (5), be placed on poidometer (1), record the quality m of testee (13);

(4) at the tensile force f 1 that the upper applying one of the piston (7) of closed container (5) top is outside, make container (5) in negative pressure state, after applying F1, the pressure P 1 in container (5) should be made to meet: 0.5atm<P1<1atm;

(5) by pressure transducer (4) and vessel temperature sensor (8), measurement obtains pressure P1, the temperature T1 of closed container (5) interior air, after applying F1, the amount of movement of piston (7) measures the volume V1 of tainer air;

(6) at the tensile force f 2 that piston (7) the upper continuation applying one of closed container (5) top is outside, and F2>F1, make container (5) continue in negative pressure state;

(7) by pressure transducer (4) and vessel temperature sensor (8), measurement obtains pressure P2, the temperature T2 of closed container (5) interior air, after applying F2, the amount of movement of piston (7) measures the volume V2 of tainer air;

(8) following formula is utilized:

$\mathrm{\&rho;}=\frac{m(P_1{T}_2-P_2{T}_1)}{(P_1{V}_1{T}_2-P_2{V}_2{T}_1)}$

Calculate the density of testee when temperature.