Refrigeration – With indicator or tester – Condition sensing
Reexamination Certificate
2002-03-12
2004-06-08
Jones, Melvin (Department: 3753)
Refrigeration
With indicator or tester
Condition sensing
C062S272000, C137S192000
Reexamination Certificate
active
06745580
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to air conditioning equipment and drain lines, and more particularly to a combination P-trap, shutoff switch, and clean-out fitting for use in a condensate drain line associated with the fan coil of an air conditioning system.
2. Brief Description of the Prior Art
In the normal operation of an air conditioning system, the evaporator or fan coil tends to be at temperatures below the dew point of the surrounding air. The resulting condensation is collected in a drain pan located under the coil, with the pan then being drained off to an appropriate disposal site such as a sewer drain or to the ground outside via a drain line. It is very common for the drain pan and/or the drain line to become plugged or clogged by debris that may fall into the drain pan or sedimentary material which accumulates in the drain line, which results in the liquid in drain pan overflowing and thereby damaging or destroying ceilings, walls and flooring.
It is common in many installations to install a capped tee-fitting or clean out in the drain line to provide access to the interior of the drain line so that a clogged or plugged drain line can be serviced by introducing air or other gas under pressure to blow the obstruction out of the drain line.
There are also devices know in the art that may be connected in the drain line to mechanically or electrically de-activate the air conditioning system when a blockage or excessive build-up of sedimentary material occurs within the condensate line.
Because of a low pressure condition that is created by the operation of the fan inside the unit, it has become conventional practice, and a requirement in many city codes, to provide a P-trap in the drain line to isolate the system from the backflow of dangerous or undesirable gases and odors that would otherwise occur when the system is connected to discharge condensate directly to the sewer.
Thus, it requires three separate fittings to be installed in the drain line in order to shut off the air conditioner to prevent liquid in drain pan from overflowing, to prevent the backflow of dangerous or undesirable gases and odors into the system, and to provide access to the interior of the drain line for clearing it of obstructions.
Therefore, it would be desirable to provide a single fitting which can be installed in the condensate drain line, which would function as a P-trap, a shut off switch, and a clean out fitting.
Others have attempted to overcome these problems, however none of the devices of the prior art are capable of performing all of the utilitarian functions of present invention.
Morrison et al, U.S. Pat. No. 4,633,673 discloses an emergency shutoff for air conditioners comprising a fitting mounted in the drain pan with a primary drain opening and a secondary or emergency drain opening for draining away fluid accumulated in the pan when the primary drain becomes blocked. A one-way valve is provided in the drain for preventing back flow of air or other fluids from the drain to the pan, and a venturi is positioned in the drain pan to produce a low pressure from the flow of air circulated by the air conditioner fan. A tube connects the venturi with a reservoir which collects the fluid drained by the emergency drain, whereby the fluid is evacuated through the emergency drain.
O'Mara et al, U.S. Pat. No. 4,693,091 discloses a condensate disposal system for an air conditioning system having a condensate tube interconnecting a condensate pan and a trap. A vent is provided in the condensate tube for relieving any internal pressure that would otherwise cause a restriction of condensate flow within the condensate tube.
Bell, U.S. Pat. No. 4,998,412 discloses a sediment alert and purging unit for a condensate drain pan and removal return line of a refrigeration system. The unit includes an element for monitoring the level of condensate within the condensate drain pan and removal line, a switch element for disabling the compressor and air handler of the refrigeration system responsive to an unacceptable level of condensate within the drain pan and removal line, and an annunciation element with the switch element to alert a user when a disabling of the compressor and air handler has occurred. The unit also includes a purge port within the condensate removal line and a first condensate line closure valve disposed upstream of the purge port. Further provided is a second condensate line closure valve disposed downstream of the purge port. Through the location of closure valves both upstream and downstream of the purge port, a clogged condensate line may be purged, either upstream or downstream of the purge port by effecting the closure of that closure valve located at that side of the purge valve opposite to where the condensate blockage is believed to exist.
Keen, U.S. Pat. No. 5,402,813 discloses an in-line algaecide dispenser having a central vertical chamber with an inlet and outlet in communication therewith in laterally opposed horizontally aligned relation and a removable cap threadedly engaged at the top end of the chamber. The dispenser is installed in a condensate or cold water drain line and a water-leachable algaecide tablet is placed in the central chamber of the dispenser to prevent growth of cold-water algae and provide protection from clogging or plugging of the downstream condensation or drain line by algae for as long as the algaecide takes to dissolve in the flowing stream of condensate.
Powell, U.S. Pat. No. 5,797,426 discloses a combination check valve and fluid trap device for connection to the outflow aperture of a condensate moisture drain system on an air conditioner, ice maker, cooler or like apparatus. The device comprises a ball float sealingly seated on a float seat within a housing, the float seat being connected to the outflow conduit of a generally U-shaped fluid trap having an inflow conduit for connection to the drain system, whereby water and gas are prevented from entering the fluid trap through the outflow conduit but excess water will move the ball float from the float seat to allow water to flow out of the outflow conduit. Preferably the fluid trap is provided with rotation means whereby the longitudinal axis of the inflow conduit can be adjusted relative to the longitudinal axis of the outflow conduit so that the two axes are not aligned in parallel.
SMD Research, Inc. of Boca Raton, Fla., manufactures and markets a safety switch, known as the Safe-T-Switch®, which is installed in an air conditioner condensate drain between the drain pan outlet and the P-trap to detect down stream clogs in condensate drains and interrupt the thermostat circuit to shut off the unit before flooding occurs. It may also be installed to activate an alarm. This device has a generally tee-shaped configuration and does not replace the P-trap.
The present invention is distinguished over the prior art in general, and these patents in particular by a combination P-trap, shutoff switch and cleanout fitting for installation in a drain line which has a hollow generally cylindrical body with a central chamber, an integrally formed tubular inlet and outlet, and a removable cap with a depending float switch which is disposed in the chamber. The float switch is electrically connected between the thermostat and air handler unit. The inlet conducts liquid from a drain pan into the lower portion of the chamber beneath a partition and the outlet conducts water from the upper portion of the chamber into the downstream portion of the drain line. When the surface of the liquid in the chamber is above the partition the device functions as a P-trap to prevent backflow of undesirable gases and odors from downstream being drawn up through the drain line by the air conditioner recirculation fan and entering into the system. As long as the float switch is in a lowermost or intermediate position, power is supplied to the thermostat, and the air conditioner operates in a conventional manner. When the downstream portion of the drain line becomes
Jones Melvin
Roddy Kenneth A.
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