JP2002243615A - Specific gravity measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a specific gravity measuring method, capable of measuring the specific gravity of such a lightweight article as floats on the water, by utilizing a specific gravity measuring device similar to conventional methods. SOLUTION: A member 2A for receiving an object to be measured is arranged in a state immersed in a liquid which is not in contact with the liquid chamber 1 inside the liquid chamber 1 housing the liquid L. The specific gravity measuring device A is provided with measuring means 11a and 12a for measuring any two elements among three measuring elements comprised of the weight in the air, weight in the liquid, and buoyancy of the object to be measured M. In the measurement of specific gravity by the specific gravity measuring device A, when the object to be measured M is similar in weight to or lighter than the liquid L in the liquid chamber 1, the object to be measured M is held integrally in a state of being immersed in the liquid with the member 2A for receiving the object to be measured via a floating-preventing member 4A to measure the weight in the liquid and/or buoyancy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific gravity measurement using a specific gravity measuring device utilizing immersion of an object to be measured in a liquid, even when the weight of the object to be measured is equal to or smaller than the liquid to be immersed. The present invention relates to a measurement method that enables the measurement.

[0002]

2. Description of the Related Art In general, to know the specific gravity of a solid object of unknown volume, the principle of Archimedes, that is, the principle that the buoyancy of an object in a fluid is equal to the weight of the fluid displaced by the object, is known. The weight of the solid article in the air and the weight of the solid article in a state of being completely immersed in a liquid having a known specific gravity (usually water having a specific gravity of 1) are measured, and the buoyancy, which is the difference between the two, is measured. The volume of the solid article is determined from (g) and the specific gravity of the liquid (g / cm ³ ), and is calculated as weight in air (g) / volume (cm ³ ).

When the liquid used is water, the weight (g) and the volume (cm ³ ) are equal, so that the value of the buoyancy (g) is directly converted into the value of the volume (cm ³ ) of the measured object. Matches. Therefore, the specific gravity of the measured object (g / cm ³ )
Is given by the following equation. Specific gravity = weight in air / buoyancy = weight in air / (weight in air−weight in water) (I) Also, since [weight in air = weight in water + buoyancy], the above equation is given by: specific gravity = weight in air / Buoyancy = (weight in water + buoyancy) / buoyancy ... (II) can also be expressed. When a liquid other than water is used, the weight in water of the above formulas (I) and (II) is defined as the weight in the liquid,
The correction may be made by multiplying the right side of both equations by the specific gravity of the liquid.

Accordingly, the specific gravity measuring device measures any two of three measuring elements a to c, which are a) the weight of the object to be measured in the air, b) the weight in the liquid, and c) the buoyancy. What is necessary is just to provide a measuring means. The weight in the liquid b is measured with the object to be immersed in the liquid as described above, and the buoyancy of c is a state in which the weight in the liquid when the object to be measured is immersed in the liquid tank is not added. It is measured as an increase in the weight of the entire liquid tank at.

In the past, specific gravity measurement was used exclusively as a means of knowing the purity of a product, but with the advancement of production technology in recent years, noble metals, alloys, synthetic resins, ceramics, rubber, fibers, and composites of these materials have been used. It is being widely used for quality inspection and analysis of solid articles made of materials and the like, and also of substances including powders and granules. For example, articles made of synthetic resin or rubber having a specific gravity of 1 or less or foams thereof, and light articles floating on water, such as hollow articles such as balls and capsules, also have quality inspection, analysis, and performance in use. There is a need for specific gravity measurement for tests and behavior tests.

However, in the conventional specific gravity measuring apparatus, one or both of b) the weight in the liquid and c) the buoyancy are measured while the object to be measured is in a submerged state, so that the object to be measured sinks in the liquid (water). There is a problem in that specific gravity measurement cannot be performed on a light object such as an article made of a synthetic resin having a specific gravity of 1 or less, a hollow article such as a ball or a capsule, or the like.

The present invention has been made in view of the above circumstances, and has as its object to provide a specific gravity measuring method capable of measuring the specific gravity of a light article floating on water using a conventional specific gravity measuring device. .

[0008]

In order to achieve the above-mentioned object, a specific gravity measuring method according to a first aspect of the present invention is provided with a reference numeral in the drawing. To
The object receiving members 2A to 2C are arranged in a non-contact and immersed state in the liquid tank 1 and a) the weight of the object M in the air, and b) the object M to be measured. Object receiving member 2A-
The weight in the liquid when held in a submerged state on 2E; and c) the total weight of the liquid tank 1 when the object M is held in a submerged state on the object receiving members 2A to 2E. Specific gravity measuring device A having a measuring means for measuring any two of three measuring elements a to c consisting of buoyancy given as increase
In the measurement of the specific gravity by using the liquid tank 1
If it is equal to or lighter than the liquid L in
The device under test M is held in a submerged state integrally with the device under test receiving members 2A to 2E via the anti-floating members 4A to 4F, and the weight in the liquid of b or / and the buoyancy of c is measured. It is characterized by:

That is, when the specific gravity value of the object M is
If the liquid L is smaller than the liquid L, it floats on the liquid surface, and even if it weighs the same as the liquid L, it drifts out into the liquid. Therefore, it is impossible or impossible to measure both the weight and buoyancy in the liquid as it is. However, by holding the object to be measured 2A to 2E in a submerged state integrally with the measured object receiving members 2A to 4F via the floating prevention members 4A to 4F, the weight and buoyancy in the liquid can be measured.
As a result, the specific gravity can be calculated based on the above equations (I) and (II). Thus, when the specific gravity value of the measured object M is smaller than the liquid L, the weight in the liquid is measured as a negative value.

According to a second aspect of the present invention, in the specific gravity measuring method according to the first aspect, the floating prevention member is set in the liquid in the liquid tank 1 by its own weight so as to cover the object M to be measured. Weight frame 4A placed on measurement object receiving members 2A to 2C
To 4D. In this case, weight frame 4A
The weight of the object to be measured M prevents lifting of the object M.

According to a third aspect of the present invention, in the specific gravity measuring method according to the first aspect, the floating member is a member for receiving the object to be measured by sinking in the liquid in the liquid tank 1 so as to cover the object to be measured M. A locking frame 4E detachably engaged with the 2D is used. That is, in the case of the mounting type such as the weight frames 4A to 4D, it is necessary to use a larger weight as the floating force of the measured object M in the liquid is larger. It can be used irrespective of the levitation force of the object M and irrespective of its own weight.

According to a fourth aspect of the present invention, in the specific gravity measuring method of the first aspect, a floating prevention member (frame portion 4F) is provided integrally with the object receiving member 2E. In this case, since the floating prevention member (frame portion 4F) and the measured object receiving member 2E are integrated, the number of components is reduced accordingly, which contributes to cost reduction.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a specific gravity measuring method according to the present invention will be specifically described below with reference to the drawings.
1 and 2 show a measuring method using a specific gravity measuring device A, FIG. 3 shows a measuring method using a specific gravity measuring device B, and FIG.
Are shown below.

The specific gravity measuring device A shown in FIGS. 1 and 2 measures the weight underwater and the buoyancy to calculate a specific gravity value. The upper first measuring device 11 constituting the first measuring section 11a is provided.
And the lower second measuring device 12 constituting the second measuring portion 12a
And the upper and lower two stages are connected and integrated on the scale body 10,
A rectangular liquid tank 1 containing water L is placed so as to be supported by the first measuring unit 11a. In the liquid tank 1, a rectangular dish-shaped object receiving member 2A having a net-like structure is provided.
Are suspended in a submerged state by the suspending member 5 and are suspended from the liquid tank 1 in a non-contact manner.

Reference numeral 13 denotes a box-shaped connecting frame, the upper plate portion of which is provided.
13d is screwed to the upper surface of the second measuring device 12. Soshi
And a space holding plate before and after the upper surface plate portion 13d of the connection frame 13.
13a, 13b and the spacing plate 1
An upper plate 13c is integrally fixed to 3a, 13b,
13c is fixed to the bottom of the first measuring instrument 11 with the screw 9b.
are doing. Therefore, the second measuring device 12 and the first measuring device 11
Are arranged by the front and rear spacing plates 13a and 13b.
The gaps 13e are provided so as to have a gap 13e therebetween.
You. Note that the spacing plates 13a and 13b are
The upper plate 13d and the upper plate 13c of the connection frame 13 are attached to each other.
Protruding plate 13a in the corresponding direction₁, 13a_Two, 13b₁, 13
b_TwoAre suspended by welding or the like, and both
a_Three, 13b _ThreeIt is formed by stoppers, etc.
It is not limited to this. In addition, the inside of the measuring instrument body 10
A computing device consisting of a microcomputer (not shown)
Abbreviation) is incorporated, and the display panel 6 is provided on the front inclined upper surface 10a.
And operation buttons 7 are provided. And the second total
The quantity part 4 is separated downward from the upper plate part 13c of the connection frame 13.
In the upright position, and stand upright apart from the first measuring instrument 11
The lower portions of a pair of left and right hanging members 5, 5 are fixed.

Each suspending member 5 is formed by bending a single metal thick wire into a substantially rectangular frame shape having upper and lower horizontal U-shaped portions 5a, 5b and front and rear vertical portions 5c, 5c. The upper horizontal U-shaped portion 5a protrudes inward beyond the upper edge of the liquid tank 1 from the upper ends of the vertical portions 5c, 5c.
The object-to-be-measured receiving member 2A is suspended via the cords 51, 51. Thus, the lower horizontal U-shaped portion 5b is continuous with the lower ends of the vertical portions 5c, 5c through a gap 13e formed by the front and rear spacing plates 13a, 13b,
Thus, the suspension member 5 is also out of contact with the connection frame 13.

In the specific gravity measuring device A having the above-mentioned configuration, if the start of measurement is indicated by the operation button 7 before the object to be measured is put into the liquid tank 1, the first measuring section without the object to be measured is provided. 11
When the weight value measured by the second weighing unit 12 is set to the reference zero point, and the object M is put into the liquid tank 1 and placed on the object receiving member 2A in a submerged state, the second Measuring unit 1
In 2, the weight increase after the measured object is charged is measured as the underwater weight of the measured object, but the underwater weight does not cover the liquid tank 1, so the weight increase measured by the first measuring unit 11 is An increase in water L corresponding to the volume of the object, that is, buoyancy. Thus, from the above formula (II), [specific gravity =
(Water weight + buoyancy) / buoyancy], the specific gravity value is calculated from the measured value of the water weight and the buoyancy, and the specific gravity value is displayed on the display panel 6.

The specific gravity measuring device B shown in FIG. 3 measures the weight in the air and the buoyancy to calculate a specific gravity value. The water L is introduced into the measuring section 14 provided on the upper part of the main body 10 of the measuring instrument. A liquid tank 1 having a rectangular shape is supported, and a mounting section 1a in the air is provided in an overhanging manner in the upper inside of the liquid tank 1. Similarly to the specific gravity measuring device A, an arithmetic unit (not shown) is incorporated in the measuring device main body 10, and a display panel 6 and operation buttons 7 are provided on a front inclined upper surface 10a.

Inside the liquid tank 1, a rectangular dish-shaped object receiving member 2B having a net-like structure is provided with a measuring instrument main body 10B.
A suspension member 8 having a lower end secured thereto is suspended in a submerged state and non-contact with the liquid tank 1. Each of the hanging members 8 is formed by bending a single metal thick wire into a substantially U-shape including an upper horizontal U-shaped portion 8a and front and rear vertical portions 8b, 8b. , 5c, the object receiving member 2B is suspended via two ropes 51, 51 at an upper horizontal U-shaped portion 5a projecting inward beyond the upper edge of the liquid tank 1. .

In the specific gravity measuring apparatus B having the above configuration, before the specific gravity measurement, the zero value is set by the operation button 7 so that the weight value measured by the weighing unit 14 without the object M is set as the reference zero point. First, the object to be measured is mounted on the air mounting portion 1a of the liquid tank 1, and the weight in the air is measured. Next, in a state where the display becomes 0, the object to be measured M is put into the water in the liquid tank 1 and placed in a submerged state on the object to be measured receiving member 2B, and the water surface of the water L is stabilized. The start of measurement is instructed by the operation button 7. Since the underwater weight of the measured object M does not reach the liquid tank 1, the value measured by the measuring unit 14 is an increase in water L corresponding to the volume of the measured object M, that is, buoyancy.
From the formulas (I) and (II), since [specific gravity = weight in air / buoyancy], a specific gravity value is calculated from the measured value of the weight in air and the buoyancy, and the specific gravity value is displayed on the display panel 6. Is displayed.

The specific gravity measuring device C shown in FIG. 4 measures the weight in air and the weight in water to calculate a specific gravity value.
A cylindrical liquid tank 1 containing water L is fixedly supported via columns 1b on an upper part of a measuring instrument main body 10 having a display panel 6 and operation buttons 7, 7 on the front side. Tank 1
The object receiving member 2C in the form of a porous cylinder is accommodated therein in a non-contact manner. The DUT receiving member 2C is a double cylindrical body 2.
And an outer cylindrical portion 21 continuous from the upper edge of the inner cylindrical portion is not in contact with the liquid tank 1 and the lower peripheral edge is a support disk 2.
2 is supported. Thus, the supporting disk 22 is placed on the measuring portion 15 on the upper part of the measuring device main body 10, and the columns 1b supporting the liquid tank 1 are inserted through the through holes 20a provided in the supporting disk 22 in a non-contact manner. are doing. 22b is the supporting disk 2
2 is a stopper lip provided on the upper surface of the outer cylindrical portion 21.
To prevent lateral displacement of the outer cylindrical portion 21 on the support disk 22. A dish-shaped in-air mounting plate 9 is detachably mounted on the upper opening of the object-to-be-measured receiving member 2C.

In the specific gravity measuring device C having the above-mentioned configuration, before the specific gravity measurement, the zero value is set by the operation button 7 so that the weight value measured by the weighing unit 15 in a state where there is no measured object is set as a reference zero point. First, the object to be measured is mounted on the mounting plate 9 in the air, and the weight in the air is measured. Next, the object to be measured is put into the water in the liquid tank 1, placed on the object receiving member 2C in a submerged state, and the operation button 7 instructs the start of the measurement with the operation button 7 when the water surface of the water L is stable. Then, the underwater weight of the object to be measured is measured. From the formulas (I) and (II), [specific gravity = weight in air /
(Weight in air-weight in water)], a specific gravity value is calculated by an arithmetic unit (not shown) in the measuring instrument body 10 based on the measured values of the weight in air and the buoyancy, and the specific gravity value is displayed on the display panel. 6 is displayed.

The specific gravity measuring devices A to C described above are intended for measuring an object to be measured which is heavier than water, and cannot measure the specific gravity of an object to be measured M which is lighter than water. That is, in any of the simultaneous measurement of the underwater weight and the buoyancy by the specific gravity measuring device A, the measurement of the second-stage buoyancy by the specific gravity measuring device B, and the measurement of the second-stage underwater weight by the specific gravity measuring device C, Must be completely immersed in water and placed on the object receiving members 2A to 2C, and the object M, which is lighter than water, rises up and cannot be measured. However, in the specific gravity measuring method of the present invention, the specific gravity measuring device A to C is used for measuring the specific gravity of an object M lighter than water by using a floating prevention member when measuring the weight in water and / or the buoyancy. Enable.

FIG. 5 shows an example of a weight frame as a floating prevention member used in the specific gravity measuring method of the present invention. This weight frame 4
A is a U-shaped frame made of a material having a large specific gravity, such as metal or ceramic, and has an upper plate portion 40a and left and right plate portions 40a.
b and 40b have slit holes 41 for liquid flow and bubble release.

According to the specific gravity measuring method of the present invention using the weight frame 4A, when measuring the underwater weight and / or buoyancy as in the embodiment shown in FIGS. 1 to 4, the weight frame 4A is measured. By placing the object M on the object M, the object M is immersed in the water L by the weight of the weight frame 4A and held on the object receiving members 2A to 2C, and measurement may be performed in this state. The zero point setting described above includes the weight frame 4A including the measurement of the weight in the air.
It is needless to say that only the measurement is performed in a state of being placed on the measurement object receiving members 2A to 2C. Thus, since the measured object M is lighter than water, the underwater weight and / or buoyancy can be measured in a completely submerged state, and the measured values are calculated as described above in each of the specific gravity measuring devices A to C. The specific gravity of the measured object M can be measured without any trouble. The underwater weight is measured as a negative value.

Therefore, according to the specific gravity measuring method of the present invention,
For example, it is possible to reliably measure the specific gravity of an article made of a synthetic resin having a specific gravity of 1 or less, or a light article floating on water such as a hollow article such as a ball or a capsule. Further, in this method, the floating prevention member, which is an independent member, is used, so that there is no problem in measuring the specific gravity of the measured object which is heavier than the original water by the specific gravity measuring devices A to C.
This means that the range of the object to be measured by the specific gravity measuring devices A to C is greatly expanded by the method of the present invention, and the usefulness of the existing device is enhanced.

The weight frame of the anti-floating member used in the specific gravity measuring method of the present invention is not limited to the U-shaped frame used in the above-described embodiment, and for example, as shown in FIG.
, And a cup-shaped weight frame 4B having a notch groove 43 on the peripheral side surface, a hat-shaped weight frame 4C composed of a weight ring portion 44 and a cover portion 45 having a mesh structure as shown in FIG. As shown in FIG. 3C, various shapes and sizes of the object M to be measured, such as a weight frame 4D formed by the weight ring portion 44 and the covering portion 46 of the wire structure, and the like, the degree of levitation, etc. Structures can be used.

The anti-floating member used in the specific gravity measuring method of the present invention includes, in addition to the above-mentioned mounting type weight frame,
It is also possible to use a locking frame which is immersed in the water L in the liquid tank 1 so as to cover the object to be measured M and detachably engages with the object receiving member. For example, the locking frame 4E shown in FIG. 7 has a substantially U-shaped frame shape similar to the weight frame 4A shown in FIG.
Outer projections 47, 47 are integrally formed at the center of the lower edge of b, 40b. On the upper surface side of a perforated plate receiving member 2D having a large number of holes 48, as shown in FIG. The two protruding pieces 47, 47 are attached to the pair of inverted L-shaped engaging pieces 23, 23 provided.
Can be fitted by sliding from the side, and thereby can be engaged with the measured object receiving member 2D.

As the above-mentioned locking frame, various shapes and structures can be adopted according to the shape and size of the object to be measured M, similarly to the above-mentioned weight frame. As the engagement means, various means such as a hook and a screw may be used in addition to the fitting structure such as the protruding piece 47. Thus, the mounting type floating prevention members such as the weight frames 4A to 4D do not require the time and effort for engaging with the measurement object receiving member, but the weight increases as the floating force of the measurement object M increases. However, there is an advantage that the locking frame can be used without being influenced by the degree of the floating property of the DUT irrespective of its own weight.

Further, in the present invention, in addition to forming the floating prevention member from independent parts such as the weight frames 4A to 4D and the locking frame 4E, the floating prevention member is integrated with the object receiving member. It may be formed. For example, the object-to-be-measured receiving member 2E shown in FIG. 9 is made of a perforated plate-like synthetic resin formed with a large number of holes 48, and has an inverted L-shaped frame portion as a floating prevention member on its upper surface side. 4F is integrally formed, and an object M lighter than water can be inserted into the inside of the frame 4F to measure the weight and buoyancy in the liquid. It is possible to measure by mounting on 4F. In the configuration in which the floating prevention member is integrated with the measured object receiving member in this manner, the number of components is reduced accordingly, so that the cost of the entire specific gravity measuring device can be reduced. Of course, the floating prevention member integrated with the measured object receiving member can be set in various forms other than those illustrated in FIG. 9.

In the above embodiment, the measured object M is lighter than water. However, the specific gravity measuring method of the present invention also measures a measured object having the same weight as water. That is, when the object to be measured is slightly heavier than water, it is likely to drift out into the liquid due to slight vibration or movement of the water, and thus cannot be stably held on the object to be measured receiving member. Although it becomes difficult to measure both the buoyancy and the buoyancy, it is possible to stably hold the object on the measurement object receiving member by using a wrapping type floating prevention member such as the weight frames 4B to 4D shown in FIG. Become.

On the other hand, in the above embodiment, water is used as the liquid to be stored in the liquid tank 1. However, if the object M is a material that does not like contact with water, the specific gravity is known according to the material. An appropriate liquid may be used. Thus, when a liquid other than water is used, the specific gravity of the DUT is obtained by multiplying the value calculated by the formulas (I) and (II) by the specific gravity of the liquid.
Even when water is used, strictly speaking, the specific gravity at 4 ° C. is 1, so if more precise specific gravity measurement is required, correction of the measured value according to the water temperature (multiplying by the specific gravity of the water at that temperature) is required. What should be done is. Such correction of the calculated value due to the difference in liquid type and water temperature is performed by incorporating a calculation program in advance in the microcomputers of the specific gravity measuring devices A to C, and inputting the specific gravity of the liquid before measurement, or in the case of water temperature. What is necessary is just to set so that it may be automatically inputted by the attached temperature sensor or the like.

The specific gravity measuring apparatus used in the specific gravity measuring method of the present invention comprises: a) the weight of an object to be measured in air; b) the weight in liquid;
Any one of three measurement elements a to c consisting of buoyancy
It suffices if a measuring means for measuring the elements is provided, and the specific gravity measuring devices A to C may have various shapes and structures of the respective components.

[0034]

According to the method for measuring specific gravity according to the first aspect of the present invention, for example, an object made of synthetic resin having a specific gravity of 1 or less, or a light object to be measured such as a hollow article such as a ball or a capsule, The weight in the liquid or / and buoyancy is measured via the levitation preventing member, and the specific gravity can be reliably measured based on the measured value, and the existing specific gravity measuring device can be used without any trouble for this measurement. .

According to the second aspect of the present invention, in the above specific gravity measuring method, a weight frame is used as the floating prevention member, so that the weight frame is used for measuring the weight in the liquid and / or the buoyancy. There is an advantage that it is only necessary to mount on the object receiving member in the inside, and the operation becomes extremely simple.

According to the third aspect of the present invention, in the above specific gravity measuring method, since the locking frame is used as the floating prevention member, the locking frame is covered when measuring the weight in the liquid and / or the buoyancy. It has the advantage that it can be used irrespective of the lightness of the measured object and irrespective of its own weight.

According to the fourth aspect of the present invention, in the above specific gravity measuring method, since the floating prevention member is provided integrally with the object receiving member, the number of components of the specific gravity measuring device is reduced. And the cost can be reduced accordingly.

[Brief description of the drawings]

FIG. 1 is an overall front view showing a cross section of a liquid tank portion of a specific gravity measuring device A used for a specific gravity measuring method according to one embodiment of the present invention.

FIG. 2 is an overall side view showing a liquid tank portion of the specific gravity measuring device A in a cross section.

FIG. 3 is an overall front view showing a liquid tank portion of a specific gravity measuring device B used in a specific gravity measuring method according to another embodiment of the present invention in cross section.

FIG. 4 is an overall front view showing a cross section of a liquid tank portion of a specific gravity measuring device C used in a specific gravity measuring method according to still another embodiment of the present invention.

FIG. 5 is a perspective view showing an example of a weight frame of a floating prevention member used in the specific gravity measuring method of the present invention.

FIG. 6 is a perspective view showing another example of the same weight frame;
(A) is a cup shape, (B) and (C) are hat shapes.

FIG. 7 is a perspective view showing an example of a retaining frame of a floating prevention member used in the specific gravity measuring method of the present invention.

FIG. 8 is a vertical cross-sectional front view of a main part showing an engaged state between the locking frame and the measured object receiving member.

FIG. 9 is a vertical sectional side view showing a configuration example in which a floating prevention member used in the specific gravity measurement method of the present invention is formed integrally with a measured object receiving member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid tank 2A-2E Measurement object receiving member 4A-4D Weight frame (floating prevention member) 4E Locking frame (floating prevention member) 4F Frame part (floating prevention member) 10 Meter main body 11a 1st measuring part (measurement) Means) 11b Second measuring section (measuring means) 14, 15 Measuring section (measuring means) M Object to be measured L Water (liquid) A to C Specific gravity measuring device

Claims (4)

[Claims] An object receiving member is arranged in a liquid tank containing a liquid in a non-contact state with the liquid tank and immersed in the liquid; a) the weight of the object to be measured in the air; and b) The weight in the liquid when the object to be measured is held in a submerged state on the object to be measured member, and c) the weight when the object to be measured is held in a submerged state on the object to be measured member. In a specific gravity measurement using a specific gravity measuring device including a measuring means for measuring any two of three measurement elements a to c consisting of buoyancy given as an increase in weight of the liquid tank, the object to be measured is the liquid tank When the liquid to be measured is equal to or lighter than the liquid in the liquid, the object to be measured is held in a submerged state integrally with the object to be measured receiving member via a floating prevention member, and the weight in the liquid of b or And / or measuring the buoyancy of (c). 2. A lifting frame, wherein a weight frame which sinks by its own weight into the liquid in the liquid tank and is placed on the object receiving member is used as the floating prevention member. Specific gravity measurement method described. 3. A floating frame as a floating prevention member, wherein the locking frame is submerged in the liquid in the liquid tank so as to cover the object to be measured and detachably engaged with the object receiving member. Specific gravity measurement method. 4. A specific gravity measuring method according to claim 1, wherein a floating prevention member is provided integrally with said object receiving member.