Patent ID: 9138548
Filing Date: 2015-09-22
Classification: A61M,H05B

Abstract:
1. A fluid warmer for tempering of a medical fluid guided in a fluid line, the fluid warmer comprising: a first and a second resistance heating element for alternating voltage; a heat exchanger thermally coupled to the first and second resistance heating elements, the heat exchanger comprising a holder for the fluid line; wherein each resistance heating element has a first and a second electrical supply connection conductor, respectively, for connection of the resistance heating elements to an alternating voltage source; wherein the first electrical supply connection conductor includes a first drivable switch and wherein the second electrical supply connection conductor includes a second drivable switch; a voltage measurement device connected to the heat exchanger and a neutral conductor of the alternating voltage source for determining a voltage between the heat exchanger and the neutral conductor of the alternating voltage source; a control device connected to the first and second drivable switch for synchronized transfer of the switches into their open switching state in dependence on the voltage; a temperature measurement device comprising an evaluation unit, the evaluation unit being connected to a temperature sensor via an electrical connecting line, where the temperature sensor is arranged on or in the heat exchanger, wherein the connecting line includes a third drivable switch which is transferable into its open switching state synchronously with the first and second drivable switches of the first and second electrical supply connection conductors; wherein the heat exchanger is electrically conductively connected to a functional grounding conductor, wherein the functional grounding conductor is provided with a fourth drivable switch, which is transferable into its open switching state synchronously with the first and second drivable switches of the first and second electrical supply connection conductors or with the third drivable switch of the temperature measurement device; wherein the control device includes a current measurement device detecting a leakage current via the functional grounding conductor; wherein the control device is programmed to jointly transfer the switches into the open switching state on occurrence of a leakage current via the functional grounding conductor, which is equal to or less than a defined minimum threshold current conduction; and wherein a respectively inversely phased alternating voltage is applied to each resistance heating element during a tempering mode; or wherein respectively in-phase alternating voltages are applied to the resistance heating elements during the tempering mode and a compensation alternating voltage, which is substantially inversely phased with respect to the alternating voltage, is applied to the heat exchanger using a compensation circuit.