Aplisens - Model SGE-25C - Hydrostatic Level Probes
The SGE-25S and SGE-25C probes are applicable to measure levels of liquids containing contaminants or suspensions. Atypical use for this probe is the measurement of levels of liquid waste in intermediate pumping stations, fermentation chambers, setting tanks etc.Measuring range: min. 0.2 m W.C., max. 0.20 m W.C.Output signal: 4.20 mA, 0.10 V .Accuracy: 0,5%
Principles of operation, design
The probe measures liquid levels, basing on a simple relationship between the height of the liquid column and the resulting hydrostatic pressure. The pressure measurement is carried out on the level of the separating diaphragm of the immersed probe and is related to atmospheric pressure through a capillary in the cable.The use of a special separator with a large uncovered diaphragm minimizes the metrological effect of sediment deposit on the diaphragm surface. This enables the probe long lifetime and proper work in contaminated media (even in the presence of abrasives, such as sand) and facilitates deaning with a delicate stream of running water (washing with water under pressure may damage the probe).The active sensing element is a piezoresistant silicon sensor separated from the medium by an isolating diaphragm. The electron c amplifier, which works in combination with the sensor, and is meant to standardize the signal, is additionally equipped with an overvoltage protection drcuit which protects the probe from damage caused by induced interference from atmospheric discharges or from assodated heavy current engineering appliances.
Installation, method of use
When lowered to the reference level, the probe may either hang freely on the cable or lie on the bottom of the tank. The cable with the capillary can be extended using a standard signal cable. For the cable connection a special Aplisens SG cable hanger is recommended. The cable connection should be situated in a non-hermetcally sealed box (the internal pressure inside the box should be equal to the atmospheric pressure), preventing water or other contaminants from getbng into the capillary. The Aplisens PP junction box is recommended For systems wilh long signal transmission lines, it is recommended the using of an additional Aplisens UZ-2 overvoltage protection circuit in the form of a wall-mounted box which allows the cables connection. When the probe cable is being wound up, the minimum winding diameter should be 30cm and the cable should be protected from mechanical damage.If there is a possibility of turbulence in the tank (for example because of the mixer operating mixers or a turbulent inflow). the probe should be installed inside a screening tube (e.g. made of PVC). The line hooked on the lifting handle can simplify the operation of the probe puling out. Cleaning the probe diaphragm by mechanical means is strictly prohibted.