Abstract: A delivery device for a primary fluid includes an elongate tubular housing containing a reservoir for the primary fluid and a chamber for an ambient fluid to which the exterior of the delivery device is exposed. The device includes an outlet from the reservoir for the primary fluid and a device for driving ambient fluid under pressure into the chamber so as to expand the chamber and to cause primary fluid in the reservoir to be displaced towards the outlet. The inlet to the driver device communicates with an opening which is exposed to the ambient fluid to which the exterior of the delivery device is exposed.

Abstract: A valve for controlling flow of a primary fluid in a primary flow channel is defined in a valve region by a deformable membrane. The primary flow channel includes a core in the valve region, and a housing which defines a void outside the primary flow channel in the valve region thereof. The valve includes a device for driving a displacement fluid into or out of the void or both, to vary the pressure difference across the deformable membrane between the primary flow channel and the void, and so as to vary the space that is available between the deformable membrane of the primary flow channel and the core for the primary fluid to flow along the primary flow channel. A pump can include a valve as described above as a driver valve, together with an inlet valve and an outlet valve.

Abstract: A delivery device for a primary fluid comprises a tubular housing which includes a reservoir for the primary fluid, and a chamber for a displacement fluid which extends coaxially with the reservoir inside the housing and is separated from the reservoir by means of a membrane. The device includes an outlet from the reservoir for the primary fluid, and a device for driving the displacement fluid under pressure into the chamber so that the membrane is deformed into the reservoir to cause primary fluid in the reservoir to be displaced towards the outlet.

Abstract: A valve for controlling flow of a primary fluid in a primary flow channel comprises a valve fluid channel, and a membrane of a porous dielectric material located in the channel so as to divide the channel into an inlet part and an outlet part and so that valve fluid flowing between the inlet and outlet parts flows through the said membrane. First and second electrodes are located for electrical communication with valve fluid in the inlet and outlet parts respectively of the valve fluid channel for application of an electric potential across the membrane in order to promote electro-osmotic flow of valve fluid through the membrane.