Abstract: Vegetation such as a weed (45) may be controlled by generating a foam comprising air and an aqueous solution comprising a surfactant; dispensing the foam so as to coat at least a base part of the weed that is to be controlled; and then injecting hot water into the foam (46) so as to contact the weed (45) below or within the coating of foam (46) The hot water causes the weed (45) to wilt and die, while the foam (46) suppresses heat loss from the hot water. The method may be carried out using a portable tool (10) which includes an air blower (14), a container (20) of a concentrate for the aqueous solution, a foam-generating tube (24) ending in an open-topped chute (26). The hot water may be provided through a flexible hose (22) from an external boiler (23), and after being used to produce the foam (46), the hot water be sprayed onto the top end of the chute (26).

Abstract: A system (10) for providing a stream of water that includes a surfactant, comprising a source (14) of water, means (32) to cause water to flow along a water supply duct (34), and a venturi injector (36) within the water supply duct. The venturi injector (36) communicates with an inlet duct (77) to supply surfactant; and the system comprises a surfactant supply duct (80, 83) that communicates between the inlet duct (77) and a surfactant container (18), the surfactant supply duct comprising a first portion that incorporates an on/off valve (38) and a second portion (83) that incorporates a check valve (84) to control flow. A plurality of surfactant containers (18) may be connected to the inlet duct (77) in this way; and each surfactant container 18 may be mounted within an open-topped chamber (68) to which hot water may be provided to heat the contents of the surfactant container (18).

Abstract: An apparatus suitable for controlling vegetation which apparatus comprises a hot-liquid reservoir (28), release means (38) connected to the hot-liquid reservoir (28) and at least one nozzle (74), for applying a stream of foam that contains steam, connected to the reservoir through the release means. The apparatus includes a heating means (34) to keep the liquid hot so the pressure is above atmospheric pressure. The liquid may be pumped by a pump (36) through the hot-water reservoir (28), the water being heated on demand by heaters (34) within the reservoir (28). The apparatus is either propelled by or mounted on a vehicle; and during use of the apparatus to control vegetation the vehicle provides power (24) to the heating means.

Abstract: An apparatus suitable for controlling unwanted vegetation which apparatus comprises a reservoir (2), release means (6) connected to the reservoir (2), and a nozzle (10) for applying a stream of foam including steam, connected to the reservoir (2) through the release means (6). A liquid is heated in the reservoir (2) to an elevated pressure, the liquid comprising water and a surfactant, i.e. a foaming agent, and forms a foam when discharged through the nozzle (10). The foam contains steam, and is effective at killing the foliage.

Abstract: An apparatus suitable for controlling vegetation which apparatus comprises a hot-liquid reservoir (28), release means (38) connected to the hot-liquid reservoir (28) and at least one nozzle (74), for applying a stream of foam that contains steam, connected to the reservoir through the release means. The apparatus includes a heating means (34) to keep the liquid hot so the pressure is above atmospheric pressure. The liquid may be pumped by a pump (36) through the hot-water reservoir (28), the water being heated on demand by heaters (34) within the reservoir (28). The apparatus is either propelled by or mounted on a vehicle; and during use of the apparatus to control vegetation the vehicle provides power (24) to the heating means.