摘要 |
A heater adapted for placement under the mattress of a waterbed consists of a flexible laminated pad having an upper layer of resistive elements embedded in electrical insulating material, and several subjacent layers of heat-reflective and thermal insulating materials. All of the layers are encased in a protective waterproof sheath. The pad may be connected in parallel with one or more similar pads and a heat sensor may be associated with each pad. In one embodiment, a control circuit is provided for supplying power to all of the pads simultaneously when all of the heat sensors detect that the temperature of the mattress has dropped below a predetermined value. In another embodiment, power may be supplied to each pad independently of the other pads.
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