Abstract: A messaging system is disclosed, delivery of messages being dependent upon the location of the recipient, the number of recipients being unlimited. The message transmitter may be fixed or mobile. The recipient may be either fixed or mobile, but must have knowledge of its own position. The transmitter broadcasts in radio frequencies (or other convenient medium) three pieces of information per message: a location, a trigger distance, and the message. The recipient, knowing its own position, calculates the actual distance to each location being broadcast. If the actual distance is less than the trigger distance, then the message is displayed to the recipient. In this manner, only messages that are relevant to the recipients' position are displayed, and messages relevant to other positions are ignored.

Abstract: A swimming pool main drain assembly comprises a cup-shaped fitting recessed in a pool bottom and having an open mouth substantially coplaner with the pool bottom. A port is provided in the fitting which communicates with the suction inlet of a circulation pump. A return port assembly is provided in the fitting which communicates with an outlet of the circulation pump. The return port assembly includes an outlet conduit which directs water in a substantially vertical direction out of the main drain and educts a portion of the pool water.

Abstract: A grey water recovery system comprises a filter tank having a filter medium therein. Grey water is delivered to the filter tank by a delivery conduit and filtered grey water is collected in a sump which surrounds the filter tank. A pump removes the filtrate to a distribution system for irrigation and similar use. The recovery system includes a backwash system. The backwash system has a flow responsive poppet valve which permits clean backwashing water and pressurized air to flow upwardly through the filter medium while closing the normal filtrate flow path to the sump.

Abstract: An improved safety needle, including a needle base, for fixing therein a rigid needle containing a hollow hub at one end, a hollow needle connected thereto and a sharp needle tip at the other end, the base defined by a proximal end and a distal end spaced-apart therefrom, the distal end of the needle base having formed therethrough a first bore concentric to the needle and covering the sharp needle tip, and a cap covering the first bore and rotatably positioned thereover, having formed therethrough a second bore, wherein the cap is rotatable between a first, safe position placing the first and second bores out of alignment and preventing passage of the needle and the sharp needle tip therethrough, and a second, armed position placing the first and second bores in alignment to allow passage of the needle therethrough to expose the sharp needle tip.

Abstract: The present invention is directed towards an air relief valve for a pressure vessel which automatically releases air from the system during filling with liquid, and which automatically seals when the liquid in the system reaches a predetermined level to prevent the liquid from leaving the system. The air relief valve of the present invention includes a valve body which provides communication between the pressure vessel and a series of output ports. These output ports are provide with a pressure indicator, a manual pressure release valve, and an automatic air relief valve. The manual pressure release valve is operable by the user to introduce air into the system, which is necessary during draining. The automatic air relief valve is generally a one-way valve, allowing air to exit but not enter the system.

Abstract: A braking system is disclosed for foot-bound roller skates, particularly in-line roller skates, consisting of a method and apparatus for activating the brake, continuously applying braking force while the brake is activated without the application of force to the activating apparatus, and stowing the brake. Preferably, the brake deploys to serve as the aft point on which the skate rides, along with one or more forward wheels.

Abstract: Hydraulic drilling apparatus and method in which a drill head is driven toward the formation being drilled by the force of the drilling fluid, and the rate of advancement or penetration of the drill head is controlled by entrapping a fluid in a chamber to resist advancement of the drill head and allowing a controlled amount of the entrapped fluid to pass out of the chamber through an orifice to permit the drill head to advance at a controlled rate.

Abstract: A pressure relief seal for pressure tanks having separable tank sections is disclosed. The seal is formed by an O-ring within an O-ring cavity, in turn formed by each tank section. Overpressurization or improper assembly of the tank sections causes the O-ring to be displaced from its sealing position to permit fluid in the tank to flow past the O-ring and through pressure relief channels at the seal.

Abstract: A pressure relief seal for pressure tanks having separable tank sections is disclosed. The seal is formed by an O-ring within an O-ring cavity, in turn formed by each tank section. Overpressurization or improper assembly of the tank sections causes the O-ring to be displaced from its sealing position to permit fluid in the tank to flow past the O-ring and through pressure relief channels at the seal.

Abstract: Hydraulic drilling method and apparatus in which the drilling fluid itself is utilized to control the direction in which a hole is bored in the earth. The drilling fluid is discharged through a plurality of forwardly facing nozzles which are inclined at different angles about the axis of the drill head, and the drilling fluid is selectively applied to the nozzles by a rotatable valve member to control the direction in which the hole is cut.

Abstract: A pump for use with a hydrotherapy tub or spa is provided wherein the compression of the pump seal located between the impeller and the drive shaft opening is controllable such that a minimum compression and thus minimum heat generation occurs at a no-load or dry condition of the pump, but maximum compression and thus maximum sealing occurs at a full-load condition. The impeller is mounted on the drive shaft in an axially movable manner with the impeller eye facing the motor so that axial loading by the impeller under load is toward the motor thus compressing the interposed seal.

Abstract: Hydraulic drilling method and apparatus in which the drilling fluid itself is utilized to control the direction in which a hole is bored in the earth. The orientation of the drill head is monitored by tilt and roll sensors, and the discharge of drilling fluid through radially or obliquely directed nozzles is controlled by poppet valves in accordance with the orientation to control the direction in which the hole is cut.

Abstract: A system for gravel packing a production radial tube terminating in an open drillhead in an oil bearing formation. The radial tube is perforated by an electrolytic perforation tool which is removed. A flexible permeable liner is passed into the radial tube and slurry is flowed through the liner and out the distal end to the radial tube back towards the well bore to the fill. Then, plug filters are placed at the proximal and distal ends of the radial tube which pass oil but not gravel, and the proximal end of the radial tube is severed, if desired.

Abstract: Hydraulic drilling apparatus and method suitable for use in a variety of applications including the drilling of deep holes for oil and gas wells and the drilling of vertical, horizontal or slanted holes, drilling through both consolidated and unconsolidated formations, and cutting and removing core samples. The drill head produces a whirling mass of pressurized cutting fluid, and this whirling fluid is applied to a discharge nozzle to produce a high velocity cutting jet. The cutting action is enhanced by abrasive material in the drilling fluid. The direction of the borehole is controlled by controlling the discharge of the drilling fluid either in side jets directed radially from the distal end portion of the drill string which carries the drill head or in a plurality of forwardly directed cutting jets.

Abstract: Hydraulic drilling apparatus and method suitable for use in a variety of applications including the drilling of deep holes for oil and gas wells and the drilling of vertical, horizontal or slanted holes, drilling through both consolidated and unconsolidated formations, and cutting and removing core samples. The drill head produces a whirling mass of pressurized cutting fluid, and this whirling fluid is applied to a discharge nozzle to produce a high velocity cutting jet. The cutting action is enhanced by abrasive material in the drilling fluid. The direction of the borehole is controlled by controlling the discharge of the drilling fluid either in side jets directed radially from the distal end portion of the drill string which carries the drill head or in a plurality of forwardly directed cutting jets.

Abstract: An air control valve is provided for use in a spa to regulate the flow of air to a hydrotherapy jet in which a recessed control knob is accessible at a rim of the spa to actuate a movable valve member to selectively constrict or dilate an air flow passage through the valve body which has an air intake opening underneath the spa rim to isolate the noise associated with the intake opening from the user.

Abstract: A submersible electric D.C. motor is provided which has a housing that seals the motor from the surrounding water and holds in a controlled atmosphere which is made to be low in oxygen content and to have free water vapor. Magnetic means are provided to transmit mechanical energy through the housing and liquid means are provided to remove heat from the motor.

Abstract: A submersible pump check valve having a housing connected to the discharge port of a submerged pump has a poppet retained by four legs operable as cantilever springs and which interact with cam surfaces within the housing to prevent removal during normal operation of the pump but to afford selective removal from the housing for cleaning or replacement of the sealing ring without removing said housing from said submerged pump. Further, the pump need not be removed or otherwise disassembled to remove the poppet.

Abstract: A cartridge filter unit particularly adapted for use in a swimming pool water purification system because of its modular design, includes a readily accessible filter body. By removing a cover, a core assembly including a solids entrapping device and an inexpensive, disposable filter cartridge contained therein may be easily withdrawn for cleaning or replacement without allowing solid pollutants collected by the filter to re-enter the system.