Abstract: A rupture disc assembly for pneumatic plugs constructed and arranged to cooperate with an aperture in an end casting of the plug to expel excess air from the plug interior when a predetermined internal plug pressure is reached. The rupture disc assembly utilizes a rupturable member in a flanged holder structure positioned in communication with the end casting aperture.

Abstract: An expandable plug device and a method for manufacturing the expandable plug. The expandable plug device has a sacrificial core which is used as an interior mold in the manufacturing process and which remains in the plug body after completion and during use. The expandable plug device is a multi-size plug having elastomeric and reinforcing layers and which may have an internal fluid flow-through conduit.

Abstract: A filament trimmer includes a rotatable trimmer head having an outwardly extending filament. The trimmer has a rear shield and a front wire guard. A cutoff blade is adjustably mounted on the rear shield to move between two different radially inward and outward positions. In the radially outward position, the cutoff blade cuts off the filament at a length in which the filament extends beyond the front guard prior to the filament becoming shortened due to breakage or wear. In the radially inward position, the cutoff blade cuts off the filament at a length in which the filament extends short of the front guard prior to the filament becoming shortened due to breakage or wear.

Abstract: A filament trimmer includes a rotatable trimmer head having an outwardly extending filament. The trimmer has a rear shield and a front wire guard. A cutoff blade is adjustably mounted on the rear shield to move between two different radially inward and outward positions. In the radially outward position, the cutoff blade cuts off the filament at a length in which the filament extends beyond the front guard prior to the filament becoming shortened due to breakage or wear. In the radially inward position, the cutoff blade cuts off the filament at a length in which the filament extends short of the front guard prior to the filament becoming shortened due to breakage or wear.

Abstract: An improved single-stage snow thrower including a wheeled frame assembly for supporting the snow thrower upon a ground surface and a driven impeller capable of being placed in ground contact to forwardly propel the snow thrower across the ground surface. A handle assembly including a user interface is further provided to permit the operator to selectively control the normal force associated with the driven impeller, and thus selectively control the propulsive drive force of the snow thrower. A bail control assembly may be provided upon the handle to permit the operator to selectively control a downward movement of the impeller to selectively control the degree of impeller ground contact.

Abstract: A one directional flow valve assembly for a fluid system. The valve assembly is comprised of a valve body having an internal valve chamber in communication with the ambient environment with a valve seat of a predetermined configuration. The assembly further has a cap structure with means to position and align a sealing membrane with respect to the valve seat. A flexible elastomeric sealing diaphragm is provided which is under tension when the diaphragm is in a sealing configuration. A carrier plate structure may be provided to position the sealing diaphragm. The sealing member is in tension adjacent to the sealing seat when in a sealing position.

Abstract: An improved single-stage snow thrower including a wheeled frame assembly for supporting the snow thrower upon a ground surface and a driven impeller capable of being placed in ground contact to forwardly propel the snow thrower across the ground surface. A handle assembly including a user interface is further provided to permit the operator to selectively control the normal force associated with the driven impeller, and thus selectively control the propulsive drive force of the snow thrower. A bail control assembly may be provided upon the handle to permit the operator to selectively control a downward movement of the impeller to selectively control the degree of impeller ground contact.

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the housing outlet and blower tube. The noise reduction is achieved by placing sound absorbing material in the blower tube. The sound absorbing material may include flared upstream and downstream ends to reduce turbulence. The sound absorbing material may be held within the blower tube by an insert frame such that substantial portions of the sound absorbing material are exposed to air passing through the blower tube. Also disclosed is a sound absorbing insert that can be placed within an existing blower tube to retrofit portable blowers with noise reduction technology.

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the housing outlet and blower tube. The noise reduction is achieved by placing sound absorbing material in the blower tube. The sound absorbing material may include flared upstream and downstream ends to reduce turbulence. The sound absorbing material may be held within the blower tube by an insert frame such that substantial portions of the sound absorbing material are exposed to air passing through the blower tube. Also disclosed is a sound absorbing insert that can be placed within an existing blower tube to retrofit portable blowers with noise reduction technology.

Abstract: An improved air inlet cover and impeller for a convertible electric blower/vacuum. The blower/vac includes an electric motor which drives an impeller. A plurality of blades located on the impeller define a frusto-conical surface of revolution. The air inlet cover includes an integral, frusto-conical pressure ring which is located offset but generally congruent to the surface of revolution defined by the impeller blades. The cover additionally includes an air grate that allows the passage of air but prevents the passage of other objects. The grate also includes a choke member for adjusting the effective area of the air inlet into the blower/vac to control the exit air volume and velocity of the blower. The cover also includes a bell-mouthed opening integral with the choke member to increase the efficiency of the blower/vac when in the blower mode.

Abstract: The present invention provides for noise reduction during operation of a portable blower by reducing the noise or acoustic energy escaping from the inlet of the blower housing. The noise reduction is achieved in one respect by placing sound absorbing material in a plenum attached to the inlet opening of the blower housing. Other features of the preferred plenum include louvered openings and angled engagement members to draw the plenum tightly against the blower housing.

Abstract: A comfort control system and method which determines the operating temperature set point for the environment to be controlled, in part by indirectly measuring the mean radiant temperature of the environment. A temperature sensor and relative humidity sensor sense the environment to be controlled and provide electrical signals indicating the sensed values to a microprocessor. A building load monitor either monitors the duty cycle of the heating/cooling system for the environment or senses the difference between the environment temperature and the outside temperature to generate a value indicative of the heating or cooling load on the building. A calculation formula to be stored in the microprocessor factors the selected operating temperature, the building load, the relative humidity, and selected constance. The microprocessor determines the operating set point, compares the set point to the temperature of the environment, and generates a control signal for the heating/cooling system.

Abstract: A method for improving cooling of a compressor element used in an air conditioning system and having a refrigerant compressor and associated drive motor hermetically sealed in a fluid-tight shell includes the steps of detecting an excessive increase in the temperature of the compressor element, intermittently operating the system during the excessive temperature detection with a superheat of a refrigerant in the system below zero superheat degrees to concurrently allow liquid refrigerant to enter the shell to enhance the cooling of the compressor apparatus by the latent heat of vaporization of the liquid refrigerant and terminating the intermittent operation and the admittance of the liquid refrigerant into the compressor element upon a detection of a desired temperature of operation of the compressor element.

Abstract: A control for the indoor air circulating fan of a heat pump when the heat pump is operating in the heating mode. After the compressor starts, the control delays the operation of the indoor fan if the temperature is below a predetermined reference temperature. The delay time increases as the outdoor temperature decreases.

Abstract: A refrigeration system comprises a compressor, a condenser, an evaporator, an accumulator, and an adjustable controllable expansion valve. An electronic control system monitors the value of superheat and accordingly provides an electrical control signal to adjust the controllable expansion valve in order to maintain a set point superheat value. An unfiltered path is provided to ensure expedient response when the system starts operation and when dynamic changes occur. A filtered path is provided to reduce hunting, or oscillations about the set point, of the superheat value during steady state operation.

Abstract: A compensation circuit for sensor lag uses a sensor temperature signal modification circuit to provide a modified sensor temperature signal for subsequent use in controlling the sensed temperature. The compensation circuit digitally compares a current sensor temperature representative signal and a sensor temperature signal at a last or preceeding sample time to produce a difference signal which is converted to a sensor slope signal and is multiplied by a sensor time constant. The resulting signal is passed through a filter to eliminate transient effects and is summed with the original sensor temperature signal to provide a sensed temperature signal for control of the temperature whereby the sensed temperature is a better estimate of the actual environmental temperature controlled by a thermostat utilizing the sensed temperature signal.

Abstract: A refrigeration system control for minimizing cycling losses of a refrigeration system having an indoor coil, an indoor coil fan, an outdoor coil, an outdoor coil fan, a refrigerant line between one end of the indoor coil and one end of the outdoor coil, a compressor apparatus and a reversing valve connecting the compressor apparatus between the other end of the indoor coil and the other end of the outdoor coil includes the steps of operating the reversing valve to a state opposite to the one representative of the operating condition of the refrigeration system for a predetermined period of time starting prior to an energization of the compressor apparatus and ending after the energization of the compressor apparatus, restoring the reversing valve to a state needed for the operating condition of the refrigeration system at the end of the period of time while continuing the energization of the compressor apparatus.

Abstract: A refrigeration system control method for minimizing off cycle losses in a heating mode of operation includes the steps of closing a valve in a refrigerant line between an indoor coil and an outdoor coil for a first predetermined period of time starting with a deenergization of a compressor and ending before a reenergization of the compressor to retain the refrigerant in the indoor coil and maintaining an energization of an indoor coil fan for a second predetermined time period after the deenergization of the compressor which second time ends before the first time period.

Abstract: A refrigeration system control method and apparatus for minimizing off cycle losses during a cooling mode of operation of a refrigeration system having an indoor coil, an indoor coil fan, an outdoor coil, an outdoor coil fan, a refrigerant line between one end of the indoor coil and one end of the outdoor coil, a valve in the refrigerant line and a compressor apparatus connecting the other end of the indoor coil to the other end of the outdoor coil includes the steps of sensing the humidity of an indoor space to be cooled by the refrigeration system to determine whether the sensed humidity is below a preset humidity setpoint level or above the preset humidity level, and controlling an energization of an indoor coil fan during a time period starting with an energization of the compressor apparatus and ending after the deenergization of the compressor apparatus and having a fan energization duration during the time period dependent on the sensed humidity.

Abstract: A multistage space thermostat control system for controlling a refrigeration heat pump and a furnace controls the heat pump from a first stage of a space thermostat and a furnace from a second stage with anticipation circuit means associated with said thermostat control system which is changed in effectiveness depending upon the operation to reduce temperature swings in the space.