A multiple pump system is disclosed. The multiple pump system may include a fluid tank and a multiple pump vessel connected to the fluid tank. The multiple pump vessel may include at least one first pump and at least one second pump located therein. In addition, the at least one first pump may be configured to dispense a fluid from the fluid tank at a first pressure, and the at least one second pump may be configured to dispense the fluid from the fluid tank at a second pressure. The first pressure may be different from the second pressure, such that the at least one first pump may be configured to dispense liquefied natural gas, and the at least one second pump may be configured to dispense compressed natural gas.

A fixed displacement hydraulic pump match flow demand control system that includes a spool valve, a plurality of fixed displacement pumps and a control valve is provided. The spool valve includes a spool. The spool is configured to shuttle within a chamber of a housing based at least in part on a pressure difference between a first end and the second end of the chamber. A fluid flow from each fixed displacement pump of the plurality of fixed displacement pumps is in fluid communication with an associated input port to the spool valve. At least one output port of the spool valve is in fluid communication with a hydraulically operated device and at least one of another output port is in fluid communication with a return. The control valve is configured to adjust the location of the spool in the chamber to regulate fluid flow to the hydraulically operated device.

An improved system, apparatus and method for injecting a chemical from a storage tank into a natural gas or liquefied petroleum gas pipeline at a flow-controlled injection rate is provided. The system, apparatus and method including a pair of positive-displacement pumps driven in substantially complementary fashion by a single driver, a controller controlling the driver, and each pump being fed from the storage tank and discharging chemical into the pipeline. The system, apparatus and method may also include a second pair of positive-displacement pumps having substantially similar displacement and operatively connected to the first pair of positive-displacement pumps, the first pair of positive-displacement pumps being driven in a substantially complementary fashion with the second pair of pumps by a single driver or a pair of drivers.

A high efficiency fluid delivery system which is particularly useful in delivering temperature-controlled air in convection heating or cooling apparatuses is described. The fluid delivery system preferably comprises fluid circulation means having an intake opening for the fluid and vanes that assist in increasing fluid velocity and reducing turbulent flow.