Reciprocating fluid pumps include a pump body including a cavity therein, a plunger located at least partially within the cavity, and a shift canister assembly disposed within the cavity. The shift canister assembly includes a sealing surface for forming a seal against the pump body. An area covered by the seal between the sealing surface and the pump body is less than about 75% of an outer cross-sectional area of the shift canister assembly. The shift canister assembly may include a shift canister and a shift canister cap attached thereto, the shift canister cap comprising the sealing surface. Reciprocating fluid pumps include a shift canister, a shift piston at least partially disposed within the shift canister, and a shift canister cap attached to the shift canister on a longitudinal end of the shift canister opposite the shift piston. Methods include forming such reciprocating pumps.

A fluid delivery device includes: a first chamber configured to receive fluid from a fluid reservoir; a second chamber configured generate a vacuum therein to apply pressure to the fluid in the first chamber to enable the fluid in the first chamber to be output from the fluid delivery device; and a flow control member configured to allow the fluid in the first chamber to flow through the flow control member into the fluid reservoir at a predetermined flow rate to decrease the vacuum in the second chamber.

Thermal energy recovery systems include a piston assembly including a primary cylinder adapted to receive vapor; a single-acting secondary cylinder/piston assembly extending from opposite ends of the primary cylinder; a primary piston disposed for displacement in the primary cylinder; first and second secondary pistons disposed for displacement in the secondary cylinder/piston; and a piston connecting member connecting the first and second secondary pistons to the primary piston. Alternatively, a secondary piston is of the type of a double-acting piston for a more compact reciprocating function to reduce piston friction losses. Metering valves regulate the vapor pressure being introduced into displacement volume chambers at a constant pressure. A working fluid pressure-tank/accumulator/transfer-conduit is in communication with the displacement volume chambers to help regulate pressure of the working fluid. A working fluid transfer conduit forms integrally with the working fluid pressure-tank/accumulator to reduce fluid friction losses.

An air-to-hydraulic fluid pressure amplifier comprising an air cylinder having an internal reciprocating air piston; a first hydraulic cylinder having a first valve fitting and a first internal hydraulic ram that is slidably positioned within the first hydraulic cylinder; a second hydraulic cylinder having a second valve fitting and a second internal hydraulic ram that is slidably positioned within the second hydraulic cylinder; a first flow control valve and a second flow control valve; a first plunger-operated pilot valve and a second plunger-operated pilot valve. Each of the first and second plunger-operated pilot valves comprises an inlet port, an outlet port, a plunger, a barrel, and a compression spring.

An air-to-hydraulic fluid pressure amplifier comprising an air cylinder having an internal reciprocating air piston; a first hydraulic cylinder having a first valve fitting and a first internal hydraulic ram that is slidably positioned within the first hydraulic cylinder; a second hydraulic cylinder having a second valve fitting and a second internal hydraulic ram that is slidably positioned within the second hydraulic cylinder; a first flow control valve and a second flow control valve; a first plunger-operated pilot valve and a second plunger-operated pilot valve. Each of the first and second plunger-operated pilot valves comprises an inlet port, an outlet port, a plunger, a barrel, and a compression spring.

Reciprocating fluid pumps include a reinforced shaft including an inner shaft and a protective cover. The protective cover at least substantially encapsulates the inner shaft. The inner shaft exhibits a greater resistance to mechanical deformation than the protective cover, and the protective cover exhibits a greater resistance to chemical corrosion by the subject fluid than the inner shaft. Methods of forming a reciprocating fluid pump include forming a reinforced shaft and positioning the reinforced shaft within a subject fluid chamber and between two plungers.

Reciprocating fluid pumps include a reinforced shaft including an inner shaft and a protective cover. The protective cover at least substantially encapsulates the inner shaft. The inner shaft exhibits a greater resistance to mechanical deformation than the protective cover, and the protective cover exhibits a greater resistance to chemical corrosion by the subject fluid than the inner shaft. Methods of forming a reciprocating fluid pump include forming a reinforced shaft and positioning the reinforced shaft within a subject fluid chamber and between two plungers.

A fluid delivery device includes: a first chamber configured to receive fluid from a fluid reservoir; a second chamber configured generate a vacuum therein to apply pressure to the fluid in the first chamber to enable the fluid in the first chamber to be output from the fluid delivery device; and a flow control member configured to allow the fluid in the first chamber to flow through the flow control member into the fluid reservoir at a predetermined flow rate to decrease the vacuum in the second chamber.

An air-driven pump system comprising: a directional unit that defines a directional air chamber and comprises a directional piston, a first process air intake, and a second process air intake; two pump units each including a liquid chamber, an air chamber, and a piston; a shaft affixed to the pistons; an efficiency valve system comprising an efficiency piston, wherein the efficiency unit is configured to divide inlet air entering the air-driven piston pump into control air, first process air, and second process air, and wherein the efficiency piston is in communication with the control air, first process air, and second process air before the air is distributed to the directional unit; and a second shaft which is in communication with the efficiency piston. The efficiency valve system is to prevent overfilling of the air chambers.

An air-driven pump system comprising: a directional unit that defines a directional air chamber and comprises a directional piston, a first process air intake, and a second process air intake; two pump units each including a liquid chamber, an air chamber, and a piston; a shaft affixed to the pistons; an efficiency valve system comprising an efficiency piston, wherein the efficiency unit is configured to divide inlet air entering the air-driven piston pump into control air, first process air, and second process air, and wherein the efficiency piston is in communication with the control air, first process air, and second process air before the air is distributed to the directional unit; and a second shaft which is in communication with the efficiency piston. The efficiency valve system is to prevent overfilling of the air chambers.