Eductor

Abstract

An eductor having an air gap, a venturi structure, and a non-return valve located in the air gap. The non-return valve is removable and allows the eductor to be operated as an air gap eductor or a non-return valve eductor. A non-return valve cartridge for installing in to the air gap of an air gap eductor, so that the eductor can be operated as a non-return valve eductor. A method of retrofitting a non-return valve in an air gap eductor.

Description

FIELD OF THE INVENTION [0001] This invention relates to eductors, for mixing liquids, and non-return valves for use with these eductors. This invention also relates to methods of adapting air gap eductors. BACKGROUND OF THE INVENTION [0002] It is common practice in many industries, such as the hotel and catering industries, for chemicals such as those used for cleaning to be purchased as concentrated liquids and then diluted with water on site to give the correct concentrations for use. Proportioning dispensing apparatus have been designed to achieve the desired dilution of the concentrated solution and dispense the mixed diluted solution. [0003] These dispensers have commonly employed so called venturi-type devices, known as eductors, to aspirate or draw the concentrated solution into the water stream. [0004] In these eductors water travelling through a passage entrains the concentrated solution at a point where a restricted flow channel in the passage widens. [0005] An eductor is ...

AI Technical Summary

Benefits of technology

[0014] An object of the present invention is to address the drawbacks of known eductor arrangements, in particular to provide a system that can be changed readily between an air gap arrangement and a non-return valve arrangement.

[0029] It is intended that the modification of an air gap eductor according to the present invention can be done by the user of the eductor and does not require a specialist technician. Thus there are substantial savings in time and money over the known approach of replacing the eductor or fitting a separate non-return valve unit.

Problems solved by technology

The inventors have recognised that with known eductors it is not possible to switch between an air gap arrangement and a non-return valve arrangement without changing the eductor unit itself.

This is expensive and time consuming.

Known eductor arrangements have limited utility in so far as a single eductor cannot be used where air gap protection and non-return valve protection are required at different times.

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