|Sensors For Physical Quantities|
Recognizing the temperature curve in the process at an early stage means that precise control is possible, thus minimizing oscillating movements within the control system. Due to the low energy input and negligible energy loss, the energy balance is at an equilibrium, and costs are reduced.
With the Pfaudler temperature probe type T, the temperature is measured exactly where needed - a thermocouple made of pallaplate has been fused into the glass layer. Fused-in input leads are used to transmit the measured values to the transducer.
Recognizing the temperature curve in the process at an early stage means to control it precisely and to minimize oscillating movements within the control system. Due to the low energy input and negligible energy loss, the energy balance is at an equilibrium, and costs are reduced.
The function of the Pfaudler temperature probe type TW is based on the fact that the electrical resistance of platinum is conditional upon its temperature. The platinum measuring unit, a PT 100 resistance thermometer, is fused into the glass layer. Fused-in input leads are used to transmit the measured values to the transducer.
These probes indicate the ”state of affairs” inside reactors and storage vessels. They may be used for continuous level detection in storage vessels or for limit level and interlayer measurement in reactors and storage vessels.
The FS/FT probes work according to the “capacitive measuring principle”. The fused-in electrode strip and the steel tube thus form a capacitor. Some of the field lines run across the glass surface through the product space. If the probe is in contact with product - instead of air - in the area of the electrode, its capacitance changes. This capacitance change is measured and displayed on the evaluation unit.
Continuous level measurement, preferably in storage vessels. The electrode strip is fused-in in parallel to the longitudinal axis of the probe carrier. The “line of action” reaches across the entire length of the probe carrier (tube or baffle).
The application range of the FT probe comprises full and empty messages for vessels, the determination of interlayers, up to the protection of pumps against running dry. The electrode is designed as an annular electrode. Pipes, flange pipes and spacer rings are used as probe carriers.
The Pfaudler temperature probe type TMI is a robust, simple, and cost-efficient solution for measuring temperature: The measuring insert - a resistance thermometer - is inserted into a glass lined baffle, a thermometer well or a valve stem and pressed to the bottom of the probe carrier by means of spring force. At the point of contact, the wall thickness of the probe carrier has been reduced, and the surface has been coated in order to ensure permanent, optimum heat transfer.
Levelpuls radar sensors are used for continuous level monitoring of corrosive liquids and inside glass lined reactors. The liquid level is measured safely, regardless of the medium and the product properties.
Levelpuls radar sensors emit microwave signals. The delay time of the signals between transmission and reception is inversely proportionate to the liquid level. It is in the range of less than one-millionth of a second.
Safe limit level detection with Safety Fill Probe
Safety Fill Probe manages to provide limit level detection with an accuracy in the millimeter range according to the principle of the vibrating fork - regardless of the density or viscosity of the medium to be measured. The probe may be used as a maximum limit switch for the upper liquid level, as an additional overfill protection, as a minimum limit switch for the lower liquid level, or as protection against running dry.
The principle is quite simple: The vibrating fork is driven by a piezo-ceramic element which makes it oscillate with its natural mechanical frequency. A second element measures this oscillation and transmits it to the integrated electronic system. The frequency changes when the fork is covered with liquid. This change is registered and converted into a switching instruction by the electronics.
For the LF probe, four rhodium electrodes are arranged one behind the other and fused into the glass layer of the probe carrier. The cell constant depends on the geometry and place of installation of the probe, and cannot be determined beforehand.
Therefore, a 4-wire circuit is used. A constant AC current flows through the product through the two external electrodes. The voltage drop is measured at the two internal electrodes and supplied to a transmitter.
Pfaudler glass monitoring probe type P with Corrosion Detector
The measuring electronics is in contact with the parts to be monitored through two point-type electrodes made of rhodium and the product.↑ Top
The Corrosion Detector works according to the principle of decomposition voltage analysis without a permanent current load on the rhodium electrodes. A voltage is applied between the two rhodium electrodes of the P probe in regular intervals, and a basic characteristic is created. On the basis of this reference characteristic, the Corrosion Detector calculates a so-called “Corrosion Alarm Window”. Then the monitoring cycle is started: A predefined voltage range is passed in defined steps in order to determine the current/voltage conditions. If these conditions are within the “Corrosion Alarm Window” in two subsequent monitoring cycles, a message will be output.