Abstract: A wheel to support a pipe, or a tower carrying a pipe, of an agricultural irrigation system, especially of a rotary type, provides a polygonal metal web with feet pivotally mounted by foot supports at the vertices of the web. The feet have relatively wide base elements for support on unstable wet earth that define depending protuberances oriented perpendicularly to the direction of travel of the wheel to minimize rut creation of waterflow along ruts in the earth being traversed. Foot supports carried by the wheel provide two spaced radially extending pivot elements about which the supported foot pivots in sequence in moving over supporting earth to lessen the vertical component of motion of the wheel.

Abstract: Automatic hot water recovery apparatus is provided for conserving the energy in a pressurized plumbing system and water heater apparatus by recovering hot water from hot water lines extending to plumbing fixtures remotely disposed from the water heater. A flow regulator is provided for automatically adjusting the flow of water from the cold water line into the hot water line as a function of operating pressure within the plumbing system.

Abstract: An expander to repair elongate thin walled pipes or tubes of larger diameter is disclosed. Similar elongate expander beams are pivotally interconnected by plural, parallel articulating links for motion toward and away from each other. One of the beams is longer than the other and carries a hitch structure that is attachable to the ordinary three-point hitch of a wheeled tractor for locomotion, positioning, and powering of the expander. Hydraulic linkage communicates angularly between the expander beams to move them toward and away from each other for use.

Abstract: Automatic hot water recovery apparatus is provided for conserving the energy in a pressurized plumbing system and water heater apparatus by recovering hot water from hot water lines extending to plumbing fixtures remotely disposed from the water heater. A piston is provided within the water heater to enable the displacement of water therein and to act as an indicator of system operation.

Abstract: An electro-mechanical auxiliary knob structure, releasably attachable to a rotatable knob of a valve, to annunciate an open condition of that valve operated thereby. The auxiliary knob pivots relative to its attachment structure to switch electric circuitry carried within the auxiliary knob to annunciate last knob motion in the direction causing valve opening. The auxiliary knob is particularly adapted for use on valves of compressed gas tanks used in gas welding.

Abstract: A heat recovery system recovers hot water to an insulated tank through reciprocally variable volume chambers which are biased to draw water from hot water lines when the pressure throughout the system is equalized. One-way valving means permits continuous water flow when desired through the hot water tank to the hot water outlet. In a specific embodiment, bias is effected by a piston having opposing faces of unequal area forming reciprocally moving walls of the chambers.

Abstract: An apparatus is disclosed for harvesting a ground crop having a stalk such as asparagus. The apparatus includes a flat blade having a holding slot for the stalks being cut located above the cutting edge. The stalks may be held in a queue in the slot until such time as a sufficient collection of stalks has accumulated for unloading. The apparatus is designed as a hand tool which may be used in such a manner to avoid bending over while harvesting the stalks.

Abstract: Heat in the hot water lines of a water system is automatically recovered by providing a bridge conduit between the cold water lines and the hot water lines and by depressurizing the hot water lines relative to the cold water lines thereby to automatically direct higher pressure cold water into the hot water lines through the interconnection, which preferably is located near the hot water outlet. The higher pressure cold water forces the hot water back into the storage tank and out of the hot water lines until pressure is equalized. Loss of unused heat trapped in the hot water lines is minimized thereby saving energy.