The KOBOLD plastic flowmeters model VKP operate on a special suspended float principle with cylindrical measuring tube and spring-loaded float with orifice. The float in model VKP-3... has slots moulded on the outside, which protect the instrument from soiling by depositing dirt particles. The danger of the float jamming is thus considerably reduced and soiled liquids with a particle size up to 400 μm can be measured without difficulty. In model VKP-2... a sharp-edged orifice in the float renders the instrument less sensitive to changes in viscosity.
The Kobold Differential Pressure Transmitter model PAD is a micro processor-based high performance transmitter, which has flexible pressure calibration and output, automatic compensation of ambient temperature and process variable, configuration of various parameters, communication with HART ® protocol.
The application is very various, as measuring pressure, flow and level by application method. All data of sensor is to be input, modified and stored in EEPROM. As an option the Kobold Pressure Transmitter is also available as a flow meter. This flowmeter model PAD-F has added the totalizing function in the PAD transmitter.
So it is available to check the flow rate and totalizing flow. It measures the flow rate by using differential pressure without compensation of temperature and static pressure. The shape of the PAD-F is the same as the standard device and it is only the terminal block which is different since there are two more terminals for the read-out of the pulse output.
The new KOBOLD type DUK flow meters are used for the measurement, monitoring, metering and dosing of low viscosity fluids. The devices work on the principle of the difference in running times. This is based on the fact that ultrasonic waves in a medium are influenced by the speed of flow. Two sensors mounted opposite one another in the pipeline function simultaneously as transmitter and receiver of ultrasound signals.
If there is no flow, then the running times of both signals are identical. If the medium is flowing, then the running time of the signal against the flow is longer than that with the flow. The running time difference, which is determined by a microprocessor, is proportional to the speed of flow. The devices can be equipped with a switching output, a frequency output or an analogue output.
In addition, a compact circuit can be selected that features a digital display, a switching output and an analogue output. The device series is rounded off by an optionally available dosing and meter circuit. The meter circuit indicates the momentary flow rate in the first line of the display and the partial or total quantity in the second line. A dosing circuit controls simple filling tasks and similarly measures flow rates, total amounts and filling amounts. The analogue output and two relay outputs can be used for further processing of the signals
The turbine flowmeter model DOT consists of a helically shaped turbine rotor supported in two tungsten carbide bearings, the rotor being solid ferritic stainless steel of a grade compatible with the metered liquid, all contained within a housing of non-magnetic stainless steel. A pick off coil having a permanent magnet core is mounted in the housing adjacent to the rotor blade tips such that a magnetic circuit is set up via the rotor blades.
Rotation of the rotor varies the reluctance of this magnetic circuit and the flux changes induce a small voltage in the coil, the frequency of which is directly proportional to the rotor speed and therefore proportional to the volumetric flow rate. The effects of increasing viscosity reduce the linear flow range and shifts the k-factor. Further, the effect of viscosity depends on the frequency (RPM of rotors). Therefore, smaller the meter, higher is the effect of viscosity on the linearity curve.