GHM Messtechnik GmbH (Germany) - When it comes to monitoring the liquid flow of low-viscosity media in cooling circuits, the Center of Competence Honsberg of the GHM GROUP offers a new series of flow monitors. The UBX series is designed with a robust metal housing and a guaranteed low-temperature range down to -50 °C for use under extreme conditions.
Longer service life, harsher conditions, more efficiency. The requirements on oil-filled transformers in various areas of applications are increasing: in, for example, wind power plants, cooling plants, CHP heating concepts, the electrical industry and in traction transformers for rolling stock, sufficient cooling must be provided so that uninterruptible operation is guaranteed.
Ice cold – even in extreme conditions:
All components of the UBX device series are designed for a guaranteed temperature range down to -50 °C to +125 °C and thus ideal for use in cooling circuits in especially harsh and rough conditions. All of the devices have a robust metal housing with a moulded seal that keeps out dust, moisture and dirt. The hermetic isolation of the flow and function part with a metal folding bellows ensures that no medium can penetrate into the inner chamber. A special segmented paddle offers protection against broken paddles.
Baffle plate principle:
Along with the construction, the function must also be designed for the extreme conditions. The UBX flow monitor operates according to the baffle plate principle: The force of the flow, which acts on the baffle plate (paddle) and moves it against the spring force. In the process, the deflection of the baffle transfers to an adjustable microswitch, which is designed for 100,000 switching cycles. The housing fulfils protection rating classes IP65 and IP67 in accordance with DIN EN 60529. Therefore, the UBX is protected against spray water and even temporary submersion. A small but crucial difference in many applications. In addition, the flow monitor fulfils the fire protection requirements of HL 2 (Hazardous Level) of DIN EN 45545-2 and the vibration requirements of DIN EN 61373 for railway vehicles.
The freedom to choose:
The UBX series can be adapted easily with various process connections and can be configured freely up to a certain degree: The user also has the freedom to choose the housing material (brass or stainless steel), the baffle plate (scoops or mono-paddle) and the switch contact (gold or silver).
Measured at the flow – a versatile solution:
With the wide temperature spectrum and the robust construction, the flow meters of the UBX series are especially well-suited for use in the cooling circuit of, for example, traction transformers for railway vehicles. Omission of a fault message would be fatal in this application, because it could bring the train to a stop in certain circumstances. Depending on the configuration (sub-floor or roof construction) and region, the flow monitors in this application are exposed to direct environmental influences, such as rain, snow, spray water or even extreme temperatures. The UBX series offers guaranteed functional reliability even in extreme temperature ranges. With the robust housing, which fulfils the requirements of Immunity class IK 09 in accordance with DIN EN 50102, no additional protection against stones is required.
An additional area of application is the monitoring of the cooling circuit of the transformers in wind power plants. In this application, the frequently fluctuating overall load spectrum of the feed currents have the consequence of heavily fluctuating temperatures, which have a negative influence on the transformer service life. Reliable monitoring of the cooling flow is also essential in cooling systems, CHP technologies and the electrical industry in order to always guarantee safe operation.
More possibilities, lower cost:
Paddle switches of the proven UBX device series are the first choice when the task at hand is monitoring larger pipe diameters with minimal pressure losses. With careful selection of the materials and the freedom of configuration up to a certain degree, the monitors can be used in a wide temperature range and in many applications and offer a crucial advantage in terms of efficiency: the baffle plate construction is more cost-effective in comparison with other monitoring principles.