Shock isolator for downhole well drilling
The disclosure provides an improved shock isolator having one or more features of: bidirectional variable metered hydraulic damping orifice; unidirectional flow valve for higher compression damping yet faster rebounding for reset; diverse spring styles for rebound and for compression; scalable back pressure for more efficient hydraulic damping; involute spline for higher torque loading capacity; progressive disk spring assemblies to expand operating frequency range and longevity; spring stack assemblies conform to establish more uniform loading during a stroke.
1 . A shock isolator for downhole well drilling, comprising:
a housing having an inner periphery; and
a damper piston subassembly having a damper piston configured to be inserted into the inner periphery, having an outer periphery smaller than the inner periphery to form an annular orifice between the housing and the damper piston subassembly, the damper piston subassembly being longitudinally moveable relative to the housing, the damper piston formed with a longitudinal variable depth damping orifice on the outer periphery of the damper piston, the damping orifice having a taper on a first end of the damping orifice, and a second taper on a second end of the damping orifice that forms a variable flow zone for fluid based on a relative position of the damper piston subassembly in the housing and configured to control a damping and response time of the shock isolator to reciprocal compression and return.
2 . The shock isolator of claim 1 , wherein the damper piston comprises a longitudinal piston opening formed inward of the outer periphery and further comprising a unidirectional valve having a sealing portion flexibly coupled over an end of the damper opening across a damper piston face and having a hub portion fixedly coupled to the damper piston face radially distal from the piston opening and configured to allow the unidirectional valve to longitudinally bend away from the damper piston face and allow flow through the piston opening in a first direction and longitudinally close over the damper piston face to restrict flow in a second direction to control a damping and response time of the shock isolator to reciprocal compression and return.
3 . The shock isolator of claim 2 , wherein the unidirectional valve comprises an alignment portion configured to engage a locating pin in the damper piston, the alignment portion having a first radius to the hub portion, and the sealing portion having a second radius to the hub portion, the second radius being greater than the first radius.
4 . The shock isolator of claim 2 , wherein the unidirectional valve comprises an alignment portion configured to engage a locating pin in the damper piston with a pin opening, the pin opening having a length radially aligned with a longitudinal axis of the damper piston and a width transverse to the length, the length being greater than the width.
5 . The shock isolator of claim 2 , wherein the damper piston comprises a limit plate coupled to the damper piston face and configured to limit bending of the unidirectional valve, the limit plate being tapered to allow the unidirectional valve to bend at an increasing distance from the damper piston face as a radial distance increases from a longitudinal axis of the damper piston.
6 . The shock isolator of claim 2 , wherein the damper piston comprises a limit plate coupled to the damper piston face, the limit plate having a relief opening aligned with a sealing portion of the unidirectional valve and configured to relieve vacuum on a backside of sealing portion when flow reverses through the piston subassembly to allow the sealing portion to return to a sealing position over the piston opening.
7 . The shock isolator of claim 2 , wherein the damper piston comprises a flow slot that is open to an outer periphery of the damper piston and configured to form a flow passage between the outer periphery of the damper piston and the piston opening.
8 . The shock isolator of claim 1 , wherein the shock isolator further comprises a splined bulkhead rotationally coupled to the housing and further comprising a lower mandrel and an upper mandrel, at least one of the mandrels having an involute spline having an involute tooth shape configured to fit a corresponding involute spline on the splined bulkhead to rotationally couple the mandrels with the housing.
9 . The shock isolator of claim 1 , further comprising a mandrel located radially inward from the housing, forming an annular spring chamber between the housing and mandrel, the spring chamber having at least two disk spring stacks separated by a disk, each disk spring stack having at least one compressible disk spring.
10 . The shock isolator of claim 9 , wherein the disk is configured to slide with less force in the annular chamber than the disk spring.
11 . The shock isolator of claim 9 , wherein the disk comprises a disk orifice for fluid flow across the disk spring stacks.
12 . The shock isolator of claim 9 , wherein the disk spring stacks comprise a first disk spring stack having a first spring constant and a second disk spring stack having a second spring constant that is different than the first spring stack constant.
13 . The shock isolator of claim 1 , further comprising a mandrel located radially inward from the housing, forming an annular first spring chamber between the housing and mandrel having a plurality of disk springs and an annular second spring chamber having a helical spring to oppose compression of the first spring chamber.
14 . A shock isolator for downhole well drilling, comprising:
a housing having an inner periphery;
a damper piston subassembly having a damper piston configured to be inserted into the inner periphery having an outer periphery smaller than the inner periphery, the damper piston subassembly being longitudinally moveable relative to the housing, the damper piston formed with a longitudinal piston opening formed inward of the outer periphery;
a unidirectional valve having a sealing portion flexibly coupled over an end of the piston opening across a damper piston face and having a hub portion fixedly coupled to the damper piston face radially distal from the piston opening and configured to allow the unidirectional valve to longitudinally bend away from the damper piston face and allow flow through the piston opening in a first direction and longitudinally close over the damper piston face to restrict flow in a second direction to control a damping and response time of the shock isolator to reciprocal compression and return; and
a limit plate coupled with the unidirectional valve and the damper piston that forms a travel space between the damper piston face and a limit plate face, the limit plate face having a taper that longitudinally progressively increases a travel space as a distance from the hub portion to the sealing portion increases.
15 . The shock isolator of claim 14 , wherein the unidirectional valve further comprises an alignment portion configured to engage a locating pin in the damper piston, the alignment portion having a first radius to the hub portion, and the sealing portion having a second radius to the hub portion, the second radius being greater than the first radius.
16 . The shock isolator of claim 14 , wherein the unidirectional valve comprises an alignment portion configured to engage a locating pin in the damper piston with a pin opening, the pin opening having a length radially aligned with a longitudinal axis of the damper piston and a width transverse to the length, the length being greater than the width.
17 . The shock isolator of claim 14 , wherein the limit plate comprises a relief opening aligned with a sealing portion of the unidirectional valve and configured to relieve vacuum on a backside of the sealing portion when flow reverses through the piston subassembly to allow the sealing portion to return to a sealing position over the piston opening.
18 . The shock isolator of claim 14 , wherein the damper piston comprises a flow slot that is open to an outer periphery of the damper piston and configured to form a flow passage between the outer periphery of the damper piston and the piston opening.
19 . The shock isolator of claim 14 , wherein the damper piston further comprises a longitudinal variable depth damping orifice on the outer periphery of the damper piston, the damping orifice having a taper on a first end of the damping orifice, and a second taper on a second end of the damping orifice that forms a variable flow zone for fluid based on a relative position of the damper piston in the housing and configured to control a damping and response time of the shock isolator to reciprocal compression and return.
20 . The shock isolator of claim 14 , wherein the shock isolator further comprises a splined bulkhead rotationally coupled to the housing and further comprising a lower mandrel and an upper mandrel, at least one of the mandrels having an involute spline configured to fit a corresponding involute spline on the splined bulkhead to rotationally couple the mandrels with the housing.
21 . The shock isolator of claim 14 , further comprising a mandrel located radially inward from the housing, forming an annular spring chamber between the housing and the mandrel, the spring chamber having at least two disk spring stacks separated by a disk, each disk spring stack having at least one compressible disk spring.
22 . The shock isolator of claim 21 , wherein the disk is configured to slide with less force in the annular chamber than the disk spring.
23 . The shock isolator of claim 21 , wherein the disk comprises a disk orifice for fluid flow across the disk spring stacks.
24 . The shock isolator of claim 21 , wherein the disk spring stacks comprise a first disk spring stack having a first spring constant and a second disk spring stack having a second spring constant that is different than the first spring stack constant.
25 . The shock isolator of claim 14 , further comprising a mandrel located radially inward from the housing, forming an annular first spring chamber between the housing and mandrel having a plurality of disk springs and an annular second spring chamber having a helical spring to oppose compression of the first spring chamber.