A control valve has a cage disposed within a valve body adjacent a valve seat and proximate a valve plug to provide guidance for the valve plug. The cage includes a solid, unitary circumferential wall with inlet passages adjacent one of an inner surface or an outer surface and outlet passages adjacent the other of the inner and outer surface. An annular cavity is spaced apart from the inner and outer surfaces and is connected to the inlet passages. Intermediate passages are connected to the annular cavity and recovery plenums interconnect the intermediate passages and the outlet passages. The recovery plenums have cross-sectional areas that are larger than a cross-sectional areas of the intermediate and outlet passages.

A fluid flow control device serving as an inflow port from a fluid reservoir (R) to the interior of a production pipe (S) is in the form of a housing (3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l). The housing has a primary flow path (18) and a secondary flow path (19). The secondary flow path is in fluid communication with a chamber (B) in which is arranged an actuator (5) for a valve device (4), the valve device arranged to open and close the primary flow path. At least one flow restrictor (1,2) is arranged in the secondary flow path, the flow restrictor arranged to provide a pressure to chamber (B) sufficient to actuate the valve to an open position when the fluid flowing through the secondary flow path is oil, and a pressure sufficient to actuate the valve to a closed position when the fluid has a viscosity and/or density less than oil.

Valve plugs having curved notches are described herein. An example valve plug includes a first section defining a first end, a second section defining a second end opposite the first end, and a third section located between the first and second sections, the third section including a curved notch formed inwardly from a periphery of the third section toward a longitudinal axis of the valve plug defined by the first, second and third sections.

A fluid flow control system serving as an inflow port from a fluid reservoir (R) to the interior of a production pipe (S) is in the form of a housing (3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l). The housing has a primary flow path (18) and a secondary flow path (19). The secondary flow path is in fluid communication with a chamber (B) in which is arranged an actuator (5) for a valve device (4), the valve device arranged to open and close the primary flow path. At least one flow restrictor (1,2) is arranged in the secondary flow path, the flow restrictor arranged to provide a pressure to chamber (B) sufficient to actuate the valve to an open position when the fluid flowing through the secondary flow path is oil, and a pressure sufficient to actuate the valve to a closed position when the fluid has a viscosity and/or density less than oil.

A dynamic variable orifice includes a housing within which are located a rotor having at least one opening extending therethrough, and at least one seat ring, having an opening therethrough, biased thereagainst. In response to a pressure spike occurring at the inlet of the dynamic variable orifice, the rotor moves axially and rotationally in the housing, to selectively align the opening in the rotor with the opening in the seat ring.

A fluid flow control device serving as an inflow port from a fluid reservoir (R) to the interior of a production pipe (S) is in the form of a housing (3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l). The housing has a primary flow path (18) and a secondary flow path (19). The secondary flow path is in fluid communication with a chamber (B) in which is arranged an actuator (5) for a valve device (4), the valve device arranged to open and close the primary flow path. At least one flow restrictor (1,2) is arranged in the secondary flow path, the flow restrictor arranged to provide a pressure to chamber (B) sufficient to actuate the valve to an open position when the fluid flowing through the secondary flow path is oil, and a pressure sufficient to actuate the valve to a closed position when the fluid has a viscosity and/or density less than oil.

A fluid flow control device includes a housing having a fluid inlet (7) and at least one fluid outlet (8). A first fluid flow restrictor (1) serves as an inflow port to a chamber (B) in the housing, and a second fluid flow restrictor (2) serves as an outflow port from the chamber (B). The first fluid flow restrictor and the second fluid flow restrictor are configured to generate different fluid flow characteristics; and the chamber (B) includes an actuating device (5a-1) that is responsive to fluid pressure changes (P.sub.2) in the chamber. The first fluid flow restrictor (1) and the second fluid flow restrictor (2) are configured to impose respective different fluid flow characteristics based on different fluid properties.

Disclosed is a device for reducing flow noise. In order to achieve a low flow noise, the device includes inlet apertures for receiving a fluid flow, chambers into which one or more inlet apertures open up, a cross-sectional area of a single chamber being larger than a combined flow cross-sectional area of the inlet apertures opening up thereto, and chamber-specific outlet apertures for forwarding the fluid flow from the chamber, a flow cross-sectional area of each outlet aperture being smaller than the cross-sectional area of the chamber, and the combined flow cross-sectional area of all outlet apertures of the single chamber being larger than the combined flow cross-sectional area of the inlet apertures opening up into said chamber.

A dynamic variable orifice includes a housing within which are located a rotor having at least one opening extending therethrough, and at least one seat ring, having an opening therethrough, biased thereagainst. In response to a pressure spike occurring at the inlet of the dynamic variable orifice, the rotor moves axially and rotationally in the housing, to selectively align the opening in the rotor with the opening in the seat ring.

A valve cartridge for a fluid end for a well stimulation pump is discussed and illustrated. The valve cartridge optionally includes: a valve body, a spring engaging the valve body on a first side thereof, and a housing at least partially enclosing the valve body and spring. The housing can define one or more passages therethrough. The housing can define one or more seats adjacent the one or more passages. The one or more seats can be configured to be selectively engaged by the valve body on a second side thereof.