It is called the hydrometer before the density meter. Conceptually, density and specific gravity have similar physical meanings, that is, describe the mass of matter contained in a unit volume per unit volume. If an object has a volume of v, its mass is m, and the gravitational acceleration is g (=0.98 m/s2), then the weight of this object is mg. At this time, the density of this object is m/v, and the specific gravity is mg/v. Obviously, there is only one gravitational acceleration g between the density and the specific gravity. Earlier we used the concept of weight, we only use the concept of density. Since the object has three basic forms of solid, gas and liquid, the densitometer also has a corresponding type. A liquid densitometer is used to measure the density of a liquid.
The liquid densitometer is tested for liquid density using the principle of a vibrating cylinder density sensor. After the liquid to be tested is pumped into the resonance tube sensor, the measurement process is performed by the single chip microcomputer, which is fast and direct, and has high sensitivity. The densitometer can be widely used for measuring various liquid densities, and with different concentration conversion software, it can directly read the concentration value or specific gravity of the corresponding liquid, such as alcohol, and can directly read the volume concentration through the processing of the single-chip software. Data, testing is easier.
The digital liquid density meter is a new density test instrument developed by combining modern microelectronics technology with Archimedes' principle. This instrument changes the cumbersome operation of traditional density test and realizes fast and accurate measurement of irregular samples. It can meet the accurate measurement requirements of sample density in the production of modern products and new materials. Calculation formula: Ï liquid = (WA-WB) x Ï / standard block V
kind
Commonly used liquid densitometers and hydrometers are digital display densitometers, float type densitometers, static pressure densitometers, vibrating densitometers, and radioisotope densitometers. Float density meter
Its working principle is that the buoyancy of an object in a fluid is related to the density of the fluid. The greater the density of the fluid, the greater the buoyancy. If the temperature of the sample to be tested is specified (for example, 25 ° C is specified), the instrument can also use the specific gravity value as the scale value. The simplest of these instruments is the visual measurement of a float glass hydrometer, referred to as a glass hydrometer.
Static pressure density meter
Its working principle is: the static pressure of a certain height liquid column is proportional to the density of the liquid, so the density of the liquid can be measured according to the static pressure value measured by the pressure measuring instrument. The bellows (see diaphragm and bellows) is a commonly used pressure measuring component. The density meter that directly measures the static pressure of the sample liquid column is called a capsule static pressure densitometer. Another commonly used is a single tube blown density meter. It measures the air pressure instead of directly measuring the liquid column pressure. The blow pipe is inserted into a certain depth below the liquid level of the liquid to be measured, and the compressed air continuously escapes from the bottom of the pipe through the blow pipe. At this time, the pressure of the air in the tube is equal to the pressure of the sample liquid column at that height, and the pressure value can be converted into density.
Vibrating densitometer
Its basic working principle is: when an object is excited and vibrates, its vibration frequency or amplitude is related to the quality of the object itself. If a volume of liquid sample is filled in an object, the change in vibration frequency or amplitude reflects the mass or density of a volume of sample liquid.
Radioisotope density meter
A radioisotope source is provided in the instrument. Its radioactive radiation (such as gamma rays) is received by a radiation detector after passing through a sample of a certain thickness. The absorption of radiation by a sample of a certain thickness is related to the density of the sample, and the signal of the radiation detector is related to the amount of absorption, thus reflecting the density of the sample.
Installation points
First, the choice of installation environment:
1. The installation position of the liquid density meter should avoid direct sunlight, vibration, wind, dust and magnetic field interference.
2. The ideal place to place is in an environment of 20 ° C / 68 ° F and humidity of 50%.
3. Verify that the voltage used matches the voltage required by the liquid density meter.
Second, the horizontal adjustment: use the horizontal adjustment foot, adjust the bubble in the level to the central position of the Lianyungang color circle, so that the whole machine is in a horizontal state.
Third, the test rack installation: the measuring frame is placed in the middle of the measuring board.
4. Container placement plate installation: Place the liquid placement plate in two concave fixing grooves on the main machine.
5. Install the windshield and place the liquid density meter in the windshield.
Function introduction
Description
Through the display screen, the density of the measured liquid can be directly read out, and 80 sets of detection data can be stored.
The host has functions such as sampling, data callback, and deletion.
Keying operation, sampling automatic liquid
Error verification is easy, just use pure water to calibrate the instrument
Product advantages
Small workload: greatly reduced workload due to lack of work such as conversion
Save resources: only 2ml per sample, reducing the waste of sample resources
High degree of automation: (1) automatic injection of peristaltic pump; (2) self-calibration; (3) inner wall free hanging treatment, easy to clean
working principle
Description
Just like squeezing a fluid-filled hose with your fingers, the fluid in the tube moves forward as the finger slides forward. The peristaltic pump is also the principle that the finger is replaced by a roller.
Peristaltic pump features:
No pollution: the fluid only contacts the pump tube and does not touch the pump body.
High precision: repeatability and high stability
Low shear: Ideal for conveying shear sensitive, aggressive fluids
?Good sealing: good self-priming ability, can be idling, can prevent backflow
Simple maintenance: no valves and seals
U-shaped oscillation tube method description
The square of the oscillation period of the oscillating tube is proportional to the density of the liquid sample filled in the tube. The design principle of the U-shaped oscillating tube is based on this, and the calculation formula is as follows:
Ï=A×P2-B
Ï -- density (density);
P -- period (oscillation period);
A, B -- U-tube constant, which is related to the mass and volume of the U-tube.
Advantages of the U-shaped oscillating tube method:
Measure true density: not affected by air buoyancy, not affected by gravity
High accuracy: not affected by human factors
? Small injection volume: only 0.1~1ml at a time
Fast measurement speed: only 1~5 minutes at a time, especially suitable for laboratory and online measurement
? Easy to control the temperature
Peltier temperature control device (Peltier)
Built-in thermostat and temperature sensor: no external temperature control, built-in temperature sensor can be calibrated and traced to many international standards.
The instrument is suitable for measuring the density of various reagents (except hydrofluoric acid), liquid food and beverage (including the elimination of bubbles in carbonic acid), petroleum liquid products and various other chemical liquid products. No need for skilled analysts, independent of the measurement environment, is the best tool for safely measuring the density and solution concentration of liquids on site.
Function introduction
? The density of the measured liquid can be read directly through the display
Can store 80 sets of test data
The host has functions such as sampling, data callback, and deletion.
Key-operated operation, automatic sampling
? Error verification is simple, just use pure water to calibrate the instrument
Product advantages
Width of range: direct measurement of liquid density from 0.00 to 1999.99 Kg/m3
?Comprehensive error is small: It can directly display the density value when the liquid temperature is 20 °C ± 0.10 °C (the temperature value can be specified by the user)
? Small workload: greatly reduced workload due to no conversion work
?Save resources: only 2ml per sample, reducing the waste of sample resources
? High degree of automation: (1) automatic injection of peristaltic pump; (2) self-calibration; (3) internal wall-free treatment, easy to clean
High price ratio: performance quality can be comparable with similar foreign products, the price is only one-eighth of the price of similar foreign products.
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