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Coffee maker
| Details |
Inventors: Thorsoe, Flemming; Andersen, Niels Lervad; Christensen, John;
Assignee: Danfoss A/S (Nordborg, DK)
Primary Examiner: Albritton; C. L.
Assistant Examiner:
Attorney, Agent or Firm:
The invention relates to a coffee maker of the type consisting of a water tank at the top, a discharge device at the bottom, connected via a pipe to an electrically heated heat exchanger which has a riser pipe with an outlet nozzle connected to its opposite end, plus a warming plate for a coffeepot to be placed under the outlet nozzle. |
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DETAILED DESCRIPTION What we claim is: 1.
A coffee maker assembly comprising a one pass heat exchanger defining a chamber and having a cold water inlet pipe and a hot water outlet pipe, said inlet and outlet pipes being fluidly connected only through said chamber, electrical heating means for and in close proximity to said heat exchanger, a power supply circuit connected to said electrical heating means, a PTC resistor in said circuit and having two separate and separated thermally conductive connections connected respectively to the upstream and downstream ends of said heat exchanger.
2.
A coffee maker assembly according to claim 1 wherein said connections are metal bridges.
Description:
In such coffee makers it is important that precautions are taken against dry-boiling and overheating of the electric heat exchanger, for instance because of incrustation.
We already know coffee makers which have, in a chamber connected to the outlet of the water tank, a float with a magnet.
When the tank is empty the float will sink to the bottom of the chamber, and the magnet will then actuate a relay, for instance a mecury relay.
When the relay is actuated, the circuit of the electric heat exchanger will be cut out.
For further protection of the heating element there may, connected in series to the said circuit, be a fuse or a thermostatic switch, for instance the type marketed under the name of "KLIXON".
It is the object of the invention to specify a coffee maker in which the temperature and the presence of water are controlled in a simple way, and in which both the float and the thermostatic switch can be spared without affecting the safety.
According to the invention this is obtained by connecting in series to the heating element of the heat exchanger a PTC resistor which is thermally connected to at least the cold-water inlet pipe.
What is obtained thereby is that the cooling effect of the PTC resistor stops when the flow of water stops after the coffee has been made, and then the PTC resistor will reach its curie temperature, will become high-resistant, and therefore the current passing through the heating element will be reduced to a negligible value
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Heat Accumulators 
