Abstract: A swimming pool chlorinator has a flow pipe that is removably attached to the inlet jet pipe from the pool circulation system and a container for chlorine-containing tablets that is located above the flow pipe. The chlorinator is submerged and the container has an opening to allow water from the pool to flow into the container and dissolve the tablets. A duct from the bottom of the container leads to the interior of the flow pipe. The duct extends into the flow pipe to constrict the flow through the pipe, so that this flow causes chlorinated solution to be aspirated from the container into the flow by means of the Venturi effect. The container is transparent so that the chlorine tablets are visible from outside the container. The container further has a removable lid for refilling the container. The container opening comprises a slotted hole in the lid, with a sliding plate that can be moved over this slot to vary the size of the opening and thereby regulate the flow through the container.

Abstract: A threshold calibration method and apparatus calibrates a reference voltage representing a selected threshold and compares the reference voltage with a measurement voltage representing a variable parameter to indicate the condition of the variable parameter. The reference voltage is set by causing the variable parameter to assume a predetermined high value and adjusting a first potentiometer to provide a first calibration voltage equal to the measurement voltage representing the high value. The variable parameter is then caused to assume a predetermined low value and a second potentiometer is adjusted to provide a second calibration voltage equal to the measurement voltage representing the low value. The first and second calibration voltages are then combined using passive resistive components to provide a reference voltage representing the selected threshold.

Abstract: A continuous liquid level measuring system having a guarded capacitance probe and related drive circuit for providing accurate level measurements, even when measuring the level of ionic and highly viscous fluids. The capacitance probe has two parallel electrodes, each constructed of a half-tube section, that are separated from each other by an insulated guard wire. The probe is excited by a 1 MHz excitation signal applied across the electrodes. The current through the electrodes is a function of the capacitance between the electrodes, which is affected by the relative permitivity of the surrounding liquid. The effects of highly viscous ionic liquids that adhere to the probe are reduced by exciting the guard wire with a guard signal that is 180.degree. out of phase from the probe's excitation signal. The guard signal changes the electric field existing in the space adjacent the junctions of the two electrodes to reduce any liquid coating effects on the level measurement.

Abstract: A probe comprising an electrically conductive polymer and a pair of electrodes is placed to be contacted by the chemical. Contact changes the molecular structure or arrangement and changes the resistivity of the polymer, which is measured to actuate an indicator and/or alarm. The probe may be incorporated in a float. The chemical detector may be combined with a water detector.

Abstract: A desoldering tool has a detachable solder collection tube interposed between the hollow tip of the tool and a source of vacuum. The tube is detached for removal of solder pellets. Within the tube is a filter preventing contaminants from being drawn into the vacuum pump. Within the tip is a cylindrical bore. Rotatable in the bore is a twisted stainless steel ribbon which allows solder to pass, but scrapes and cleans the bore.

Abstract: Dispenser for liquids requiring use of one hand, particularly useful for motorists, has a collapsible plastic bag with a delivery spout enclosed in an insulated casing adapted for mounting on the ledge above the dashboard of a vehicle. Swivelled to the device is a cup holder which positions the cup under the spout for dispensing liquid and away from the spout for convenient removal and replacement of the cup. Only one hand is required to activate the spout, swivel the holder, and grasp the cup. The bag may be refilled as required either through the spout with the bag in the casing or by opening the casing and removing the bag.

Abstract: A hand-held, trigger-actuated tool heats solder to be removed from a workpiece and draws the melted solder into the distal tip of the tool by vacuum. From the tip, the molten solder is drawn into a relatively large diameter, thin-walled, extended tube in which the solder hardens into pellets which may be removed as required by removing a plug in a chamber at the near end of the tube. A solenoid in the handle of the tool operates a plunger in a cylinder which communicates with the top of the chamber through a duct. The plunger has a one-way valve in its head which has a sealing disk which "floats" in the head, and on the return stroke of the plunger permits air trapped in the cylinder head to escape.

Abstract: A hand-held, trigger-actuated gun heats solder to be removed from a workpiece and sucks the molten solder from a hollow tip through a small-diameter suction tube into a larger-diameter chamber from which it may be removed at intervals through a discharge tube. The tip placed in contact with the solder is heated by a heater of the type used in soldering irons. A cylinder communicates with the chamber in such manner that solder is not drawn into the cylinder. The piston in the cylinder is actuated either by a solenoid energized when the trigger is pulled or by a mechanical linkage connected to the trigger.

Abstract: The capacitance probe consists of a vertical insulated wire stretched taut in the tank, or other container, where liquid level is to be measured. Fittings at the top and bottom conveniently and efficiently support and tighten the wire. The system comprises an oscillator which impresses a sinusoidal voltage in series with the probe, preferably through a transformer so that there are no active electronics at the probe. One end of the probe is at ground potential. A long transmission line may connect the probe to the measuring electronics.