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Title: Wastewater heat recovery method and apparatus

Patent ·
OSTI ID:10166468

This invention is comprised of a heat recovery system with a heat exchanger and a mixing valve. A drain trap includes a heat exchanger with an inner coiled tube, baffle plate, wastewater inlet, wastewater outlet, cold water inlet, and preheated water outlet. Wastewater enters the drain trap through the wastewater inlet, is slowed and spread by the baffle plate, and passes downward to the wastewater outlet. Cold water enters the inner tube through the cold water inlet and flows generally upward, taking on heat from the wastewater. This preheated water is fed to the mixing valve, which includes a flexible yoke to which are attached an adjustable steel rod, two stationary zinc rods, and a pivoting arm. The free end of the arm forms a pad which rests against a valve seat. The rods and pivoting arm expand or contract as the temperature of the incoming preheated water changes. The zinc rods expand more than the steel rod, flexing the yoke and rotating the pivoting arm. The pad moves towards the valve seat as the temperature of the preheated water rises, and away as the temperature falls, admitting a variable amount of hot water to maintain a nearly constant average process water temperature.

Research Organization:
Savannah River Site (SRS), Aiken, SC (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
AC09-89SR18035
Assignee:
Dept. of Energy
Patent Number(s):
PATENTS-US-A7718518
Application Number:
ON: DE93015715; PAN: 7-718,518
OSTI ID:
10166468
Resource Relation:
Other Information: PBD: 1991
Country of Publication:
United States
Language:
English