In hospitals and clinics particularly, water or other fluids can easily become contaminated with harmful microbes such as E. Coli and the like from the washing of patients or surgical instruments. Such water may then be discharged into a sink for subsequent discharge into a sanitary system. Hospital sinks are often provided with gas traps (known as "P-traps") in drain lines, and the traps may provide excellent breeding grounds for many types of hazardous microbes. Such microbes, when allowed to grow unchecked, may travel upwardly through the sink drain line and into the sink where a susceptable individual may come into contact with them and become infected. The usual gas traps which are employed in drainage systems are often hard to reach and in any event are difficult to sterilize or decontaminate.
Prior art solutions to this problem have involved the use of air gaps in the drain lines of sinks, coupled with drainage holding tanks and pump assemblies, the air gap providing a discontinuous barrier for the return travel of microbes through the drainage system into a sink. Such prior art solutions, it will be understood, have involved the use of expensive and complex equipment. The existence of an air gap in the line, of course, provides a risk that the line may overflow through the air gap.
U.S. Pat. No. 3,985,994 shows an apparatus which can be mounted in the drain of a sink, and which can be heated to prevent the spread of microbes. This device provides a thermal barrier in the form of a heated metal ring into which microbes must come in contact during their travel upwardly into a sink. The ring is electrically heated, and hence the possibility exists of transmitting electricity from the ring to the water in the drain and thence to the sink. In the event the water is contaminated with ionizable materials such as salt, a possibility exists of a user of the sink receiving a shock. Moreover, the heated metal ring may conduct heat rapidly in an axial direction along the drainline in which it is mounted, and further may transfer heat rapidly to water or other drainage fluids passing therethrough.
A thermal barrier for microbes in a drainage system which would require only very small amounts of electric power, which would dissipate heat to the drainage and to adjacent structures only very slowly, and which would serve as an electric insulator between the drainage and the electric heat source, is much to be desired. Desirably, a barrier of this type should be relatively inexpensive and easy to install. It should be substantially maintenance free.