Tunable fluid end

#The invention relates generally to reciprocating pumps, and more specifically to vibration and vibration effects in such pumps.

#Reciprocating high-pressure pumps (commonly called fracking or frac pumps) are often used in oil and gas fields for hydraulic fracturing of rock formations to increase hydrocarbon yields. Such pumps are typically truck-mounted for easy relocation from well-to-well. And they are usually designed in two sections: the (proximal) power section (herein “power end”) and the (distal) fluid section (herein “fluid end”). Each pump fluid end comprises at least one subassembly (and commonly three or more in a single fluid end housing), with each subassembly comprising a suction valve, a discharge valve, a plunger or piston, and a portion of (or substantially the entirety of) a pump fluid end subassembly housing (shortened herein to “pump housing” or “fluid end housing” or “housing” depending on the pump configuration).

#For each pump fluid end subassembly, its fluid end housing comprises a pumping chamber in fluid communication with a suction bore, a discharge bore, and a piston/plunger bore. A suction valve (i.e., a check valve) within the suction bore, together with a discharge valve (i.e., another check valve) within the discharge bore, control bulk fluid movement from suction bore to discharge bore via the pumping chamber. Pulsatile fluid flow through the pump results from periodic pressurization of the pumping chamber by a reciprocating plunger or piston within the plunger/piston bore. Suction and pressure strokes alternately produce wide pressure swings in the pumping chamber (and across the suction and discharge check valves) as the reciprocating plunger or piston is driven by the pump power end.

#FIG. 1 is a schematic 3-dimensional view of a partially sectioned tunable check valve assembly/tunable radial array embodiment showing how an adjustable preload flange constrains an area of the viscoelastic reservoir element as described herein.

#FIG. 2 includes a schematic 3-dimensional exploded view of the tunable check valve assembly/tunable radial array embodiment of FIG. 1 showing viscoelastic body elements, the valve body, and the adjustable preload flange.

#FIG. 3 is a schematic 3-dimensional partially-sectioned view of viscoelastic reservoir, groove and fenestration elements (i.e., viscoelastic body elements) of FIGS. 1 and 2 showing the constrained area of the reservoir element where it contacts an adjustable preload flange, as well as an adjacent unconstrained area.

#Tunable fluid end embodiments comprise a family, each family member comprising a fluid end housing with at least one installed tunable component chosen from: tunable check valve assemblies, tunable valve seats, tunable radial arrays and/or tunable plunger seals. Installing one or more tunable check valve assemblies, for example, facilitates selective attenuation of valve-generated vibration at its source. The likelihood of fluid end failures associated with fatigue cracking and/or corrosion fatigue is thereby reduced. Adding tunable valve seats, tunable radial arrays and/or plunger seals to tunable check valve assemblies in a fluid end further facilitates optimal damping and/or selective attenuation of vibration at one or more predetermined (and frequently-localized) fluid end resonant frequencies. Optimized vibration attenuation (via, e.g., optimized fluid end damping) is provided by altering resonant frequencies in each tunable component in relation to one or more (measured or estimated) fluid end resonant frequencies and/or tunable component resonant frequencies.

#In general, a tunable (suction or discharge) check valve of the invention may comprise, for example, a combination of a tunable check valve assembly/tunable radial array 99 (see, e.g., FIG. 1) and a tunable valve seat 20 or a tunable valve seat 389 (see, e.g., FIGS. 7 and 11). Details of the structure and functions of each component are provided herein both separately and as combined with other components to obtain synergistic benefits contributing to longer pump service life.

#FIGS. 1 and 2 schematically illustrate an invention embodiment of a tunable check valve assembly/tunable radial array 99 substantially symmetrical about a longitudinal axis. Illustrated components include a valve body 10, an adjustable preload flange 30, and a plurality of viscoelastic body elements 50. Check valve body 10, in turn, comprises a peripheral groove 12 (see FIG. 2) spaced apart by an annular (central) reservoir 16 from a longitudinal guide stem 14, groove 12 being responsive to longitudinal compressive force. A plurality of viscoelastic body elements 50 comprises an annular (central) reservoir element 52 coupled to a (peripheral) groove element 54 by a plurality of (optional) radial fenestration elements 56 (in fenestrations 18) to form a tunable radial array. Groove element 54 functions as a vibration damper and valve seal, comprising at least one circumferential tubular area 58.