Kees van der Westen Mirage Duette Standard

Each Kees Van Der Westen machine machine is custom fabricated by order, superbly hand-crafted with only the highest mastery and finest materials.

Heat-Exchange System

The Mirage's heating system is based on the thermo-syphon system. It consists of one large copper boiler (13L for the Duette), equipped with a heat-exchanger (HX), for each group, running vertically slanted across the boiler. This HX is connected to the rear of the group by a thick tube running from top of HX to group and another tube running from rear of group to bottom of HX, completing a vertical circuit.

The water in the HX is heated by the hot water and steam surrounding the HX in the large boiler. This is an extremely quick  way to heat water, thanks to the massive energy in the 125 degrees C. steam boiler and the fast heat transferring capabilities of the copper. It is far more efficient than a heating element. The capacity of the HX therefore may remain relatively small. We use HX`s of 450cc per group.

Heat always wants to go up: the heated water becomes lighter and moves upwards. This flow of hot water leaves the HX, enters the thick tube attached to the top of the HX, then runs towards the group. The group is installed slightly higher than the top of the HX.

Brass Group

The group is a massive 4 kg made from brass. Brass is a top heat transferring material, which soaks up heat from the water when this enters the 35cc chamber at the rear of the group. The group becomes hot, the water losing much of its heat becoming heavier and starts to sink through the lower thick tube, running from rear of group to the bottom of the HX. Arriving there, the water re-enters the HX, heats up again and all starts anew. The temperature inside the HX is much higher than the normal operating temperature for the group. Capacity to heat the group is thus ensured very well.

Thermo-Syphon Loop System

This thermo-syphon loop, travelling up from HX to group, then returning to bottom of HX, is driven solely by the heat inside the large boiler.

There is no pump or any other device. When the machine is on and at idle (no coffee being made), the thermo-syphon loop is flowing constantly all by itself. As heating the water inside a closed system also means pressure will rise, there is an expansion valve installed. This is adjusted at the workshop to start releasing drops at 11-12 bar. The group solenoid valve has a rating of 15 bar and may act as a secondary expansion valve for extra safety.

55 years after its creation, the E61 thermo-syphon system is still considered a technically elegant system — the thermal efficiency particularly impresses and easily surpasses the popular multi-boiler systems. In comparison, the double or multi-boiler system, can technically be regarded as rather run of the mill.

For 40 years the Italian espresso machine industry, although widely adopting the thermo-syphon idea, did not take any initiative to continue its development. Instead, its innovators opted for a different route: they went back in time and revived the old idea of designating separate boilers for steam and coffee production. Kees van der Westen embodies the finest of either system.

Key Features:

• Auto-back-flush program, all groups pressurize and discharge simultaneously 8 times.
• Energy saving hot water system. Some cold is added to the hot water, so less heated water is needed. This mix provides a steady stream with the correct temperature to prepare Americanos. The hot water is controlled by a quick to adjust timer.
• Choice of touch pad to activate the group, offering 4 automatic volumes plus continuous, or the Bastone lever, offering 2 automatic volumes plus continuous. The touch pad can easily be swapped for a Bastone bracket, or vice versa, even later.
• Drip tray adjustable in height, optionally a raised tray for espresso cups is available.
• Stainless steel filter holders with KvdW POM handles.
• PID controlled temperature, with energy saving Eco mode for nights and/or weekends.
• Standard equipped with a Progressive Pre-Infusion Cylinder per group. This allows a finer grind, creating more surface, so a higher yield in the cup, less chance on channeling, preventing fines to travel down.
• Wide choice in filter baskets, both sizes as types.
• Rubber group gaskets remain flexible forever, do not become hard or brittle.
• Membrane type group screen, very nice dispersion, less coffee sucked up by discharge of pressure at end of extraction. Remains clean longer.
• Heavily protected heating element (extra safety level probe, cut-out switch with feeler against element in water, machine shuts down when any of the solenoid valves remains open for longer than 120 seconds).
• Entire frame in stainless steel only, powder coated in crackle black.
• Large boiler capacity: 13L with Duette.
• Elevated position of body, easy cleaning of bar surface.

Additional Custom Options

• Bastone or Touch Pad
• Foot Steam Petal
• Sandblasted Logo in Side Panel

Please call for more information.