A vent valve for a buoyancy control device (“BCD”) suitable for divers, where the valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained. An automatic buoyancy control device suitable for free-swimming divers, providing the functions that may include a controlled ascent rate, controlled descent rates, the imposition of a maximum depth limit, the facility to hold a set depth and to follow a dive profile or decompression profile. The device, control process and subsystems provide a high safe failure fraction.

An exemplary embodiment of a combination valve assembly comprises a valve housing, an overpressure vent valve, a fill valve and a movable liquid overfill seal. The valve housing includes a longitudinal axis. The overpressure vent valve relieves excess pressure from the tank to which the assembly is affixed. The fill valve includes a fill valve pin actuatable between an open and closed configuration. The overfill seal is movable between a fluid sealing position and a fluid releasing position, and is elastically biased toward its fluid sealing position. In its fluid sealing position, the overfill seal prevents liquid from escaping the tank through the dip tube and outward of the valve assembly. Actuation of the fill valve pin toward its open position and movement of the overfill seal toward its fluid releasing position are preferably configured to both occur in the same direction, which is substantially parallel to the longitudinal axis.

Aspects and techniques of the present disclosure relate to a bleed valve system for bleeding fluid of a first, lower, specific gravity from a fluid of a second, higher, specific gravity, in a fluid system. The techniques can be used to provide a bleed valve system, for a pressurized fluid system, that is not sensitive to rotational orientation around a mounting axis.

A valve including: a chamber configured to extend at least partly into a tank and to be connected via an upper venting aperture to a venting circuit; and a shut-off point defining a single maximum filling level within the tank, located away from the chamber, the shut-off point being in fluid communication with the chamber via a conduit, wherein the conduit includes a venting tube.

Aspects and techniques of the present disclosure relate to a bleed valve system for bleeding fluid of a first, lower, specific gravity from a fluid of a second, higher, specific gravity, in a fluid system. The techniques can be used to provide a bleed valve system, for a pressurized fluid system, that is not sensitive to rotational orientation around a mounting axis.

Disclosed is a urea injection device for a selective catalyst reduction device. The urea injection device for a selective catalyst reduction device serves to inject urea into a urea tank through a urea injection port and a urea injection line that connects the urea injection port and the urea tank. The urea injection device may include: i) a leveling pipe which is connected with the urea tank, ii) a separator which is installed to be connected with the leveling pipe, and connected to the urea injection port through a gas recirculation line, iii) a gas vent line which is connected with the separator, and iv) a check valve which is installed in the gas vent line.

A vent valve for a buoyancy control device suitable for divers, where the valve may be opened by any combination of over-pressure, manual pressure relief or a powered means, where a force to a valve plug is applied by means of a spring that is constrained to prevent entirely lateral and angular movement but in which movement of the plug in the axis of the seat is unconstrained.