Abstract: A pump with an outer housing defining an enclosure, an inlet for admitting fluid into the outer housing and an outlet for expelling fluid from the outer housing, a piston for selectively modulating a first fluid pressure, such that the first fluid pressure is associated with a location proximate the inlet, and a member that selectively isolates a second pressure associated with a location proximate the outlet from the first fluid pressure. The pump may also include a first chamber within the outer housing for receiving fluid admitted into the pump from an ambient environment and through an inlet to the pump, a second chamber within the outer housing for receiving fluid from the first chamber, and a piston that both (i) selectively controls the flow of fluid from the first chamber to the second chamber and (ii) selectively expels the fluid from the second chamber into the ambient environment.

Abstract: A pump with an outer housing defining an enclosure, an inlet for admitting fluid into the outer housing and an outlet for expelling fluid from the outer housing, a piston for selectively modulating a first fluid pressure, such that the first fluid pressure is associated with a location proximate the inlet, and a member that selectively isolates a second pressure associated with a location proximate the outlet from the first fluid pressure. The pump may also include a first chamber within the outer housing for receiving fluid admitted into the pump from an ambient environment and through an inlet to the pump, a second chamber within the outer housing for receiving fluid from the first chamber, and a piston that both (i) selectively controls the flow of fluid from the first chamber to the second chamber and (ii) selectively expels the fluid from the second chamber into the ambient environment.

Abstract: A watertight pump having a plunger used to causing air to be expelled from a nozzle of the pump. The plunger forms an interior compartment accessible by removal of a cap of the pump.

Abstract: A pump with an outer housing defining an enclosure, an inlet for admitting fluid into the outer housing and an outlet for expelling fluid from the outer housing, a piston for selectively modulating a first fluid pressure, such that the first fluid pressure is associated with a location proximate the inlet, and a member that selectively isolates a second pressure associated with a location proximate the outlet from the first fluid pressure. The pump may also include a first chamber within the outer housing for receiving fluid admitted into the pump from an ambient environment and through an inlet to the pump, a second chamber within the outer housing for receiving fluid from the first chamber, and a piston that both (i) selectively controls the flow of fluid from the first chamber to the second chamber and (ii) selectively expels the fluid from the second chamber into the ambient environment.

Abstract: A relief valve is configured to fit between the outlet of a hand pump and the inlet of an inflatable device to prevent the inflatable device from being inflated beyond a desired pressure. The relief valve can also be used to bleed excess air out of an inflatable device that is above its desired pressure.

Abstract: A hand pump for inflating rafts or similar inflatables has a first piston with a relatively low pumping volume which is capable of pumping relatively small volumes of air into a raft as the raft becomes full and is approaching its maximum pressure, and a second piston with a larger pumping volume that can pump larger volumes of air into a raft when it is empty or only partially filled. Both pistons are operated with a single plunger. When the plunger is rotated in a first direction to a first position a locking mechanism allows it to operate only the first piston, and when the plunger is rotated in a second direction to a second position the locking mechanism allows it to operate only the second piston.