Sensors For Physical Quantities
Index
Pfaudler temperature probe type T
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.
- High mechanical strength and chemical resistance through use of glassed steel
- No sealing elements - optimum operational reliability
- Up to 6 measuring locations may be arranged on a single probe carrier
- Small measuring element - excellently suitable for installation on small components, such as valve cones or spacer rings
- Power supply units are supplied on request
- Suitable for use in potentially explosive atmospheres of zone 1 if appropriate transducers are used
- Probe in flange design approved for zone 0 in accordance with EC type examination certificate PTB 03 ATEX 2132X
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TEMPERATURE PROBES TYPE TW
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.
- High mechanical strength and chemical resistance through use of glassed steel
- No sealing elements - optimum operational reliability
- Can be fused into the glass layer of a baffle, a Quatro-Pipe or a thermometer well
- Up to three measuring locations may be arranged on a single probe carrier
- Power supply units are supplied on request
- Four-wire circuit with constant current
- Probe in flange design with suitable measuring transducers in accordance with EC type examination certificate PTB 03 ATEX 2132X approved for zone 0
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LEVEL PROBES TYPE FS/FT
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.
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FS Probe
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).
- High mechanical strength and chemical resistance through use of glassed steel
- No sealing elements - optimum operational reliability
- The measuring circuit is intrinsically safe and, as the probe itself, approved for zone 0. EC type-examination certificate PTB 03 ATEX 2132X
FT Probe
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.
- High mechanical strength and chemical resistance through use of glassed steel
- No sealing elements - optimum operational reliability
- The measuring circuit is intrinsically safe and, as the probe itself, approved for zone 0. EC type-examination certificate PTB 03 ATEX 2132X
TEMPERATURE PROBES TYPE TMI
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.
- High mechanical strength and chemical resistance through use of glassed steel
- Fully glass lined probe carrier - no gasket in the product space
- Can be inserted into a baffle, a thermometer well or a valve stem
- Robust, and thus reliable, design
- Measuring insert is easy to replace
- Measuring accuracy with 1/3 Class B to DIN 43 760 / ICE 751
- The measuring transducer and power supply units are supplied on request
- Suitable for use in potentially explosive atmospheres of zone 1 if appropriate transducers are used
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LEVEL MEASURING PROBE LEVELPULS
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.
- Deviation of characteristic including linearity, repetition and hysteresis < 0.1%
- No long-term drift
- Accurate measurement also in the case of varying temperatures
- Adjustment even without filling or emptying the reactor
- Low transmission frequency - insensitive to product deposits
- Possibility of using two-conductor technique
- Communication capability: HART Profibus PA
- Allowable working temperature inside reactor: -40 to +200°C
- Allowable working pressure inside reactor: -1 to +16 bar
- Approval for potentially explosive atmosphere, zone 0, according to ATEX
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SAFETY SWING PROBE
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.
- High mechanical strength and chemical resistance through use of glassed steel
- No sealing elements - optimum operational reliability
- Safety Fill Probe can be installed in any orientation: horizontally, vertically, inclined
- Faultless functioning even with foam, bubbles and suspended particles
- Approved as overfill protection according to WHG (Clean Water Act)
- The annual inspection required under WHG is performed by simply pressing a button - the probe remains inside the vessel
- Approved for zone 0
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LF CONDUCTIVITY PROBE
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.
- High mechanical strength and chemical resistance through use of glassed steel
- Thermometer wells, baffles or spacer rings may be used as probe carriers
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P MEASURING PROBE
Pfaudler glass monitoring probe type P with Corrosion Detector
The P probe provides for constant monitoring of the quality of the glass surface of reactors and their internal parts, which may be decisive for the process. In connection with additional measuring electronics, reliable information can be obtained in all viable cases on the condition of the reactor and the systems connected to it.
The measuring electronics is in contact with the parts to be monitored through two point-type electrodes made of rhodium and the product.
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Corrosion Detector
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.
- No unnecessary false alarms - clear alarm message in the event of corrosion only
- Also works if metallic materials are built in
- Exact mA values are assigned to the operating statuses
- No installation required - the electronics is integrated in the probe’s terminal box
- Power supply with two-conductor technique
- Use of commercially available power supply units
- Compatible with all P probes as of 1983
- Explosion protection: II 2 (1) G, or II 2 G EEx ia IIC T6, or EEx ib IIC T6
- EC type-examination certificate PTB 03 ATEX 2117X
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