I. Installation Method for Submersible Level Gauges
The immersed level transmitter is a widely used and common level measurement device, frequently applied in settings such as water treatment plants, urban water supply systems, sewage treatment facilities, high-rise building water tanks, mines, wells, industrial water pools, water tanks, oil tanks, hydrogeology, marine environments, reservoirs, and river channels. Its installation and usage are particularly convenient; a simple installation method involves securing the instrument head and directly immersing the sensor end into the water. There are two specific installation methods: one for still water conditions and another for flowing water conditions. The installation procedures for both situations are detailed below:
(1) Installation method of submersible liquid level gauge under static water conditions:
When installing a submerged level transmitter in static deep wells or pools, the probe of the transmitter is directly placed at the bottom of a steel pipe with an inner diameter of about φ45 mm. Several small holes are drilled at different heights along the pipe to allow water to flow freely into it. The cable (junction box) is then secured at the opening of the container using a nylon strap or an adjustable tripod mounting bracket.
(2) Installation Method for Submersible Liquid Level Transmitters Under Flowing Water Conditions:
a. When measuring the liquid level in flowing or agitated liquids, the submersible level transmitter is usually installed inside a steel pipe with an inner diameter of approximately φ45 mm (with several small holes drilled at different heights on the side opposite to the liquid flow direction to allow liquid to enter the pipe smoothly) that is fixed in the liquid. The submersible level transmitter is then placed into the steel pipe for operation.
b. The submersible level transmitter should be installed vertically, and the installation position should be kept away from liquid inlets, outlets, and agitators.
c. In applications with significant vibration, steel wire can be wound around the submersible level transmitter to absorb vibrations and prevent the cable from being pulled or broken.
II. Advantages and Disadvantages of Submersible Level Gauges
The submersible liquid level transmitter is an emerging, cost-effective product in the current market. It can output signals remotely and also provides local display. The working principle of the submersible liquid level transmitter is based on the proportional relationship between the static pressure of the measured liquid and its height. It utilizes the piezoresistive effect of diffused silicon or ceramic sensing elements to convert static pressure into electrical signals, which are then transformed into a standard 4-20mA DC current signal output. The sensor part of the submersible liquid level transmitter can be directly immersed into the liquid, and installation can be done using flanges or brackets, making it extremely convenient to set up.
The submersible liquid level transmitter is directly immersed in the liquid, making installation and use highly convenient. It has no moving parts, ensuring high reliability.
Now, let’s discuss it from the perspective of its working principle. Of course, it has both advantages and disadvantages.
Advantages: High measurement accuracy; convenient installation; signals can be transmitted remotely for control; it can resist corrosion from various media by selecting different materials; suitable for explosion-proof environments; and moderately priced.
Disadvantages: The measurement signal needs to be converted; it cannot measure high-temperature media exceeding 125°C; and the density of the measured medium must be uniform and consistent.
III. Handling of Frequent Faults in Submersible Level Gauges
Compared to traditional level gauges, the most notable feature of the submersible level gauge is that its sensing device no longer comes into direct contact with the measured medium. The advantage of this design is that it prevents sensor clogging, avoids damage caused by corrosion, extends the service life of the submersible level gauge, reduces the failure rate, and broadens its application scope. However, some recurring faults can still affect the measurement performance of submersible level gauges.
1. No result indication
Sometimes, after the measurement work is completed, the display device does not show any data. Do not rush to conclude that the device is damaged. This is likely a problem with the power supply. If the supply voltage is less than 18V, automatic power-off or incorrect wiring of the instrument can also cause this situation. You need to first check the wiring and the circuit.
2. Current output is always 4 mA
It may be due to a leak in the float or the pressure guiding tube. In addition to checking for damage in specific parts, the tightness of the connections between components should not be ignored. You should reseal using appropriate materials according to the nature of the medium.
3. Current output is greater than 20 mA
It may be that during the measurement of a pressurized container, the compensation air port was not set on the instrument, or the air port is damaged. Install or replace the damaged compensation air port.
4. Output is slow or even unchanged
Check the float. This situation is related to excessive impurities in the float and blockage of the pressure guiding tube, which can cause the sensor to fail to receive pressure signals. Unblocking the pressure guiding tube will solve the problem.
There are many other common faults related to submersible level transmitters. Only a few with high occurrence rates are listed here, and the methods are just for your reference. If the current problem still cannot be solved, it is recommended that you contact the professional technicians of the manufacturer to help you troubleshoot.
