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Basic Introduction of Static pressure level transmitter
Dec 17, 2018

Basic Introduction of Static pressure level transmitter


Static pressure level transmitter is widely used to measure the level of atmospheric pressure, pressure vessels, its use is characterized by differential pressure sensor and electronic circuit encapsulated in the top of the container under test, and the liquid under test, and easy to install and adjust, but also to increase its reliability, security.The probe is made of stainless steel specially machined cylinder gas collector, anti-fouling, anti-clogging, and no empty tank is required for installation.It provides digital differential pressure compensation, automatic temperature compensation.At the same time, because it has the function, the zero point and the range adjustment mutually independent characteristic, causes it to become a kind of unique liquid level transmitter.The working principle is to use hydrostatic pressure of the head to measure the liquid level, and change this pressure into (4 ~ 20)mA signal output, which is composed of the main parts of the collector, pressure pipe, connector and internal package differential pressure transmitter

Basic Introduction of Static pressure level transmitter

First, the principle of static pressure level transmitter

1. The static pressure type liquid level transmitter is based on the principle that the measured hydrostatic pressure is proportional to the height of the liquid, and the static pressure is converted into an electrical signal by using the piezoresistive effect of the foreign advanced isolated diffusion silicon sensitive element. It is then converted to a standard electrical signal (typically 4 to 20 mA) by temperature compensation and linear correction.

2. Static pressure level transmitter is suitable for liquid level measurement of various media in petroleum, metallurgy, electric power, pharmaceutical, water supply and drainage, environmental protection and other systems and industries. The compact structure, simple adjustment and flexible installation make it easy for users to use. Standard signal output methods such as 4 to 20 mA, 0 to 5 v, and 0 to 10 mA are optional by the user as needed.

Second, the static pressure type liquid level transmitter technical characteristics

1. Applicable medium: medium coexisting with 316 stainless steel, butyl rubber and polyvinyl chloride

2. Measurement range: 0-60mH2O

3. Accuracy: 0.5%; 0.25%; 0.1%;

4, medium temperature: -40 ° C ~ 80 ° C (medium no crystal), beyond this range can be used thread or flange type bottom pressure, with an isolator.

5, the ambient temperature: -40 ~ 70 ° C

6, long-term stability: ± 0.1% range / year

7, the power supply voltage: 12 ~ 36VDC

8, the output signal: two-wire system 4 ~ 20mA

9, load characteristics: standard 24VDC, load resistance ≤ 600Ω

10, protection level: IP68

11, explosion-proof grade: ExdIIBT4

Third, static pressure level transmitter structure and materials

1. Transmitter relay box: cast aluminum, 100×68×110, epoxy resin coating;

2, the transmitter probe: 1Crl8Ni9Ti, ∮ 29 × 150, anti-corrosion is ∮ 44 × 140;

3. Air guiding cable: 6-core PVC cable with diameter ∮7, and anti-corrosion cable sheath is PTFE;

 Fourth, the details of the static pressure level gauge:

     The static pressure level gauge is produced by the original German SENSE pressure sensor. It is mainly used for urban water supply and drainage, water treatment plants, reservoirs, rivers, oceans, oil storage tanks, and oil, chemical, electric power and other departments. The test medium can be water, oil, acid, alkaline and viscous liquid. The instrument outputs two-wire 4~20mADC standard current signal, which has the advantages of advanced technology, high precision, stable and reliable quality, convenient installation and use, etc. It is an ideal liquid level instrument in the process detection and control system.

     The static pressure level gauge is based on the principle that the measured hydrostatic pressure is proportional to the height of the liquid. The piezoresistive effect of diffusing silicon or ceramic sensitive components is used to convert the static pressure into an electrical signal. Temperature compensated and linearly corrected. Converted to 4-20mADC standard current signal output. The sensor part of the static pressure level gauge can be directly put into the liquid, and the transmitter part can be fixed by flange or bracket, which is very convenient for installation and use.

 

Basic Introduction of Static pressure level transmitter

Main technical indicators of static pressure level gauge:

Accuracy: 0.5% FS (on-site header indication accuracy 2.5% FS)

Measuring range: 0~2, 5, 10, 20, 50, 170m

Power supply: 24VDC

Output current 4~20mADC (two-wire system)

Load resistance: 0 ~ 620Ω

Level overload: 2 times

Operating temperature: -25 to +70 ° C

Storage temperature: -40 ~ +125 ° C

Measured medium: liquid that can coexist with 316 and 1Cr18Ni9Ti stainless steel and rubber

Threaded interface: M14*1.5, length 15mm

Dimensions: diameter Ф 28mm, length 170mm

Five, use precautions

(1) Carefully confirm whether the instrument is in proper working condition. Note that the power supply voltage is 24V DC.

(2) The transmitter and the pressure guiding tube are exposed to the air, so it is not suitable for use in strong corrosion.

(3) Gases and organic solvents that are lighter than air may damage the transmitter.

(4) If it is predicted that there is strong fluctuation, only the hard pulse tube can be used, and it should be considered to be installed in a standpipe.

(5) The measured liquid ratio change needs to be re-calibrated.

(6) The assembled device must be inserted vertically into the liquid

Six. Problems that are easily overlooked

(1) The gas at the connection between the pressure guiding tube and the collector is easy to leak, so be careful when installing.

(2) The interface between the pressure guiding tube and the collector tube and the transmitter should be sealed with 4 fluorine belt or #567 sealant. The glue should be allowed to dry for one hour before immersion to form an airtight whole.

(3) Air/steam cannot be discharged from the pressure pipe, and there is no obvious air bubble at the joint.

(4) Since the silicon sensor may be affected by the process, it can only be used for liquids that do not destroy neoprene and plastic.