Safety cooler
A safety cooler is an assembly that is used in water cooling systems for oil hydraulic units to cool the working medium with water.
To cool larger stationary hydraulic systems, shell- and- tube heat exchangers are often used, in which the hydraulic oil is cooled by water. This heat exchanger is usually located in a separate circuit that is driven by its own circulating pump and also includes an oil filter. When available, water from surface waters or wells is often used for cooling. The return flow is fed back into the water or sink well.
If the heat exchanger leaks, there are two risks:
- The hydraulic oil can get into the cooling water return and so get into surface water or the absorption well (as long as the pressure in the oil circuit is higher than the water pressure)
- the cooling water can penetrate the hydraulic oil and make it unusable. Larger amounts of water in the system can lead to consequential damage. in extreme cases, the tank can overflow (with the circulation pump switched off)
The safety cooler is a special design of the tube bundle heat exchanger. The individual tubes are double-walled and the space between them is filled with a barrier fluid. The barrier medium is designed so that it is neither harmful to the oil circuit nor to the wastewater. During the manufacture of the cooler, this liquid is pressurized by a diaphragm accumulator to a pressure which is higher than the pressure in the oil circuit. This pressure is monitored by a pressure switch. If there is a leak between the water circuit and the barrier medium or the oil circuit and the barrier medium, the pressure in the accumulator is reduced and the pressure switch responds. The oil and water circuits are then still separated by one of the two pipe walls. When the pressure switch responds, the control can carry out a suitable error reaction (warning signal, switching off the circulation pump, closing the cooling water valve ...).