Schwämmle Cools

Laser Technology

NWK Cooling Device for Diode Lasers

NWK Cooling Device for Diode Lasers

The water coolers of series NWK have been developed for the supply and cooling of internal cooling circuits, particularly of Nd YAG or diode lasers. They can be used along with various cooling agents (e.g. de-ionized water, oils etc.). However, this must be provided for during the design phase. The temperature is adjustable, however, it cannot be lower than the temperature of the cooling water. Thus, it is interconnected between the consumer and an existing cooling system (cooling unit, cooling water circuit). If no cooling water is available, the water cooler will be delivered in connection with a compressor cooling unit. Depending on the demands that are placed on the temperature behaviour, various control systems can be used. Therefore, the water cooler can also be employed for temperature stabilization. A temperature constancy of up to ± 0.1 K is possible.

The device is constructed in a way that it can be adapted to customer requirements. Temperature control is effected via an electronic thermostat with digital indicator. Temperature constancy with this electronic thermostat is 1 K. A higher temperature constancy is possible.

Structure and Function


The water cooler has got its own tank containing the cooling agent, an all-welded heat exchanger made of stainless steel, supply pump, temperature control equipment and respective monitoring sensor system. This produces a closed internal circuit: Tank – pump – consumer – tank. The device is constructed in a way that it can be adapted to customer requirements. Normally, a ion exchanger is installed in the bypass if de-ionized water is used. There is a particle filter in the flow line, its fineness of filtration can be selected. Since the capacity of the heat exchanger – and that means the capacity of the water cooler – naturally depends on various parameters like temperature difference between cooling circuit and external cooling water and water quantities, these parameters should be known before dimensioning of the device is carried out - or at least the rough values. These values will then serve as a basis for the dimensioning of the heat exchanger. Besides, the dimensioning of the heat exchanger has considerable influence on the control behaviour.

Technical Details

The device is arranged on a plate and delivered either as a 19″ slide-in unit or as a complete unit in a complete sheathing (with rollers upon request). The device is fully wired and piped internally. All switches, fault indications, level indicators and control etc. are installed in the front plate. The tank, which is large-dimensioned in relation to the total size of the device, is made of Makrolon. The rotary pump is made entirely of stainless steel and is therefore corrosion-free. The heat exchanger is of a double cross-flow type and also all-welded and made of stainless steel (material 1.4404). The entire piping consists of stainless materials; the cooling water piping consists of PE tube and brass fittings. The connections at the tank consist of unplasticized PVC. Diverse safety equipments and devices from flow control device, pressure monitor, conductance monitoring through monitoring and indication of water quantity and current cooling capacity to the connection to an overall control system or a computer can be selected as options. Simply send us your specification!

Temperature Control

Maintaining a desired temperature depends on various factors. Generally, the water cooler is available with two different temperature controllers. Standard is a temperature constancy of ± 1 K. For a temperature constancy of < 0.5 K another regulating system is used. We either use a parameterizable digital controller with PID action or an analogue controller. If required, a radiator can also be installed as an option if the device is used for temperature control and not only for cooling.


  • Small dimension and high cooling capacities at the same time
  • Available as a 19″ slide-in unit or as a device in an enclosure
  • Internal cooling circuit without soiling, algae and calcification
  • Ion exchanger in the bypass
  • Controller can be adapted to customer requirements
  • Broad power spectrum: Cooling capacities of up to approx. 40 kW possible
  • Fault messages can be switched to interlock, if required; interfaces for computer connection or for connection to an overall control system possible
  • Front plate design according to customer requirements possible

Download data sheet (PDF)

Technical details, performance calculation etc. at a glance