Controllable vacuum systems with surface condensers
The cooling water used in steam jet vacuum systems is sometimes subjected to fluctuations in outdoor temperature. As a result, the water temperature varies in summer and in winter. For these applications Körting vacuum systems are fitted with control units. These allow automatic adjustment of the minimum motive steam consumption required for the cooling water.
A jet ejector’s motive steam can be changed in two ways. On the one hand by reducing the motive steam pressure and on the other by altering the motive nozzle’s cross section (by using a nozzle needle). Experience has shown that using nozzle-needle control has proved particularly effective. It harnesses the maximum expansion ratio via the motive steam nozzle, resulting in low motive steam consumption. Electric or pneumatic actuators generate an axial displacement of the nozzle needle and therefore control the mass motive flow.
Because the control unit alters consumption, energy costs are cut, but performance is maintained. In comparison with non-adjustable designs, vacuum systems that allow adjustment entail higher investment outlay. However, due to the energy costs saved, the return on investment is very quick.
A reduction in motive steam consumption