Issue date: May 23, 2000.

This load-shifting control system selectively allocates multiple electrical loads between a first power source and a second power source. It includes a processor coupled with multiple transfer switches connected to the electrical loads.

The processor is configured to identify available combinations of the loads and to select a preferred combination as a function of control parameters and/or demand data. The processor then sends control signals to the transfer switches to provide an allocation of loads according to the preferred load combination.

The system is capable of selecting a load combination which reduces peak demand requirements for the utility and reduces peak demand charges for the customer. In addition, the system is capable of allocating loads between two power sources both for load shifting and for emergency backup purposes.

U.S. Patent 6,047,718:

Solenoid valve having coaxial armatures in a single coil design.

Inventors: Steven J. Konsky (St. Louis, MO); John J. Love (St. Louis, MO); and Mike C. Santinanavat (Chesterfield, MO).

Assignee: Emerson Electric Co. (St. Louis, MO).

Issue date: April 11, 2000.

This solenoid valve consists of a coil, a pair of armatures including an inner armature, which slides within a coaxial outer armature and the outer armature which slides within the coil, and a pair of valves.

One of the valves is on the outer armature extending from the coil, and the other valve is on the inner armature extending from the valve-bearing end of the outer armature. Thus, both valves are at the same side of the solenoid valve assembly.

When a magnetic force is applied by a current flowing in the coil, the inner armature is drawn into the coil, opening the valve at its end. An increased magnetic field caused by increased current in the coil results in the outer armature being drawn into the coil, thereby also opening the valve at the end of the outer armature.

The device thus provides an electromagnetically operated valve that is suitable for controlling gas flow in such equipment as a gas furnace, gas water heater, gas space heater, gas boiler, etc.

U.S. Patent 6,060,719:

Fail-safe gas furnace optical flame sensor using a transconductance amplifier and low photodiode current.

Inventors: Joseph DiTucci (Simsbury, CT); Stephen K. Phelps (Chillicothe, IL); and Martin F. Zabielski (Manchester, CT).

Assignee: Gas Research Institute (Chicago, IL).

Issue date: May 9, 2000.

This invention provides a gas furnace optical flame-sensing device consisting of a photodiode flame sensor operating in a photovoltaic short-circuit mode. The photodiode flame sensor is designed to produce a low-output electrical signal when a flame is detected.

A feedback network designed to conduct the low-output current from the flame sensor causes the transconductance amplifier to output a voltage high signal. A voltage comparator then compares the voltage high signal with a threshold voltage in order to provide a logic level output signal for input to a microprocessor. The processor determines whether a gas flame is present.

The system also includes a fail-safe test circuit designed to provide a test signal, to check the functionality of the detector, both when a flame signal is present and also not present, to verify its operability.

U.S. Patent 6,065,296:

Single package vertical air conditioning system.

Inventor: Gary K. Feger (San Antonio, TX).

Assignee: U.S. Natural Resources, Inc. (San Antonio, TX).

Issue Date: May 23, 2000.

The design of this single package vertical air conditioning system is said to be versatile in that a single unit can be installed in an outer wall of a building and have ducts directed to multiple rooms. Thus, the unit provides the convenience of a through-the-wall packaged terminal air conditioner (ptac), while providing the function of a unitary or split-system air conditioner.

Extensive ductwork is not necessarily needed. The unit has a slim profile, which enables it to be recessed in the back corner of a closet, or at the intersection of two rooms with an outer wall. By installing it in this manner, it permits the unit to accommodate various floor plans.

The device uses a telescoping plenum which allows the system to be uniformly manufactured and yet can be installed in a variety of openings through the outside wall.

The equipment allows the delivery of chilled air to the left or right or in both directions. There-fore, delivery may be local and/or remote into separate rooms.

U.S. Patent 6,065,948:

Discharge check valve in a scroll compressor.

Inventor: Jerry E. Brown (La Crosse, WI).

Assignee: American Standard Inc. (Piscataway, NJ).

Issue date: May 23, 2000.

This invention describes a discharge check valve assembly for a scroll compressor. The valve is maintained open by the flow of discharge gas during normal compressor operation and is not susceptible to chatter due to the momentary gas backflow and/or momentary pressure pulsations, which can repetitively occur during operation. At the same time, the valve is quickly responsive to close the discharge port upon compressor shutdown.

The valve also is not susceptible to sticking open due to the adhesive forces created between the valve element and its seat by the oil film that will be present when the compressor is in operation.

The check valve consists of a valve element that moves into a valve cage by the discharge of gas upon compressor start-up, and is maintained there as long as operation continues.

Upon compressor shutdown, the valve element immediately moves out of the valve cage and away from the valve stop, to close the compressor discharge port against backflow.