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Biomedical subjects

L B HALL

Publications and source records attributed to L B HALL.

15 recordsLinked to original sources
PubMed1959

The regulation of flow through residual spray nozzles. 2. Flow control orifices in soft rubber discs.

A sharp-edged orifice in a disc of rubber with a durometer tolerance of 35 to 40, properly mounted near the nozzle tip, is capable of regulating the discharge from a compression sprayer with an accuracy at least comparable to that of mechanical pressure regulator valves. The orifice can act as a flow control device under varying hydraulic pressures because of reduction of the diameter and change of the shape of the orifice under the fluid pressure on the upstream face of the disc. This is possible since, to maintain a constant rate of discharge, the diameter of the orifice need only be changed inversely as the fourth root of the pressure and the square root of the coefficient of discharge. Erosion of the orifice and "set" of the rubber, two potential causes of inaccurate flow, tend to cancel each other out.The device is best used in combination with an 8003 nozzle tip. The rubber discs can be produced commercially at a reasonable cost. Field trials of the combination are recommended.

Equipment and Supplies↗
PubMed1959

The regulation of flow through residual spray nozzles. 1. Metering orifices in polyethylene discs.

Used residual spray nozzles, which have been discarded because of the increase in discharge rates, may be used again if their discharge rates are reduced by a metering orifice placed in the nozzle tip. A suitable orifice in a polyethylene disc is described. On the basis of laboratory test results, such a disc appears to be an inexpensive and satisfactory metering device for use in combination with worn spray nozzles.

Equipment and Supplies↗
PubMed1955

Suggested techniques, equipment, and standards for the testing of hand insecticide-spraying equipment.

The new demands placed upon application equipment by the introduction of modern insecticides have revealed the deficiencies of this equipment when required for continuous use on a large scale. If adequate equipment is to be produced, specifications must be based not only on basic materials tests but also on "use" tests, in which the conditions of field use are simulated.THE AUTHOR OUTLINES SUGGESTED TECHNIQUES TO BE FOLLOWED AND STANDARDS TO BE ADOPTED IN TESTING THE PERFORMANCE OF COMPRESSION SPRAYERS AND ALLIED EQUIPMENT, WITH REFERENCE TO THE FOLLOWING FEATURES: compression-sprayer tank fatigue; tank impact; pump resistance to bursting; pump resistance to collapse; pump friction; cut-off valve durability; constant-pressure valves; cut-off valve actuation; hose flexure; hose tension and bursting-pressure; hose friction; gaskets, valve faces, and similar non-metallic parts; nozzle-orifice erosion; and nozzle pattern.

Insecticides↗