JPH08271398A - Specific gravity measuring method for liquid material using load cell - Google Patents

Abstract

PURPOSE: To provide a specific gravity measuring method using a small detector portion easy to handle and manufacture and capable of continuously extracting data on the on-line basis. CONSTITUTION: A solid body 1 having the specific gravity larger than that of pure water is suspended by a fine wire in a container 3 containing a liquid material to be tested, the load is detected by a load cell 2, and it is processed by a load cell amplifying circuit 5 and an A/D converting circuit 6. The weight of the solid body 1 in the liquid material is compared with the weight in the pure water and the weight in the air measured in advance by an arithmetic circuit 7. The calculated specific gravity value is continuously outputted from an output circuit 8.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for measuring the specific gravity of a liquid substance.

[0002]

2. Description of the Related Art A conventional hydrometer is a batch type such as a float type or a type in which a reference liquid is installed near a substance to be tested and a comparison value with a reference liquid is constantly taken out.

[0003]

The conventional method has the following drawbacks. (B) It is very difficult to continuously retrieve data online with a batch method such as a float method. (B) In addition, it is necessary to strictly create the size and specific gravity of the float to be added to the liquid. (C) Further, even if it is an online type, a liquid (pure water or the like) as a comparison reference is always required, and the apparatus becomes large in size.

[0004]

[Means for Solving the Problems] A solid (1) having a higher specific gravity than the liquid substance and pure water is hung by a thin wire or the like in a container (3) containing the liquid substance, and the load is detected by a load cell (2). The load cell signal amplification circuit (5) and the AD conversion circuit (6) are processed, and the weight of the solid (1) measured in advance in pure water and in air is compared with the arithmetic circuit (7). Then, the calculated specific gravity value is continuously output from the output circuit (8). The weight of the solid (1) in pure water and in air can be measured again at any time, and the data is recorded in the storage element in the arithmetic circuit (7).

[0005]

The buoyancy acts on the object in the liquid, and its magnitude is proportional to the volume of the object and the specific gravity of the liquid. Therefore, the specific gravity of the liquid can be obtained by measuring the weight of the object in pure water, air, and the liquid under test. Since the load cell (2) outputs a voltage proportional to the load, this output voltage is amplified and calculated as a weight value. Based on the relative weight values of the solid (1) in pure water and in air measured before the start of the specific gravity measurement, the ratio of the buoyancy in pure water and the buoyancy in the liquid substance under test based on the relative weight values during the measurement of specific gravity. Is required. Specific gravity of pure water is 1
Therefore, the specific gravity of the liquid substance under test can be calculated immediately.

[0006]

[Examples] A liquid substance to be tested and a solid (1) having a specific gravity higher than that of pure water are suspended in a container (3) containing a liquid substance with a thin wire or the like, and the load is detected by a load cell (2) to amplify the load cell. Processed by the circuit (5) and the AD conversion circuit (6),
The weight of the solid (1) measured in advance in pure water and in air is compared with the arithmetic circuit (7), and the calculated specific gravity value is continuously output from the output circuit (8). If a programmable controller (sequencer) is used for the control part (9), online control can be easily performed in a production line such as a factory. Data output can be display, digital data, or analog data. Further, by providing a sensing circuit in the load cell amplifier circuit, the length of the signal cable (10) can be 100 m or more, and a strain gauge may be used instead of the load cell.
Moreover, if the shape of the suspended solid is devised, the specific gravity can be obtained with considerable accuracy even in the moving liquid substance.

[0007]

The specific gravity data is continuously output from the output circuit (8) instead of the batch type like the float type. In the case of this device, each weight measurement value (output voltage) need not be an absolute value but may be a relative value. Therefore, the solid to be suspended in the liquid substance to be tested does not have to be strictly made in volume and specific gravity, and may be hollow. Also, by installing a sensing circuit in the load cell amplifier circuit, the signal cable (1
Since the length of 0) can be 100 m or more, the detector part (4) and the control part (9) can be installed separately. Therefore, it can be made much more compact than the conventional online type.

[Brief description of drawings]

FIG. 1 is a signal block diagram of the present invention.

[Explanation of symbols]

 1 Solid suspended in liquid substance 2 Load cell 3 Container containing liquid substance to be measured 4 Detector part 5 Load cell signal amplification circuit 6 AD conversion circuit 7 Arithmetic circuit 8 Output circuit 9 Control part 10 Signal cable

Claims (1)

[Claims] 1. A specific gravity measuring method for measuring the specific gravity of a liquid substance by detecting the weight of a solid suspended in a liquid substance by a load cell and comparing it with the weight in air and in pure water.