# US 2008/0185141 A1 · Plunger lift system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2008/0185141 A1 - Document ID: US20080185141A1 - Status: Published application - Kind: A1 - Application number: 12/027,062 - Filed: 2008-02-06 - Published: 2008-08-07 - Earliest claimed: 2007-02-06 - Assignees: Stellarton Technologies Inc. - Inventors: Ryan AMIES; Grant GEORGE; Jordan JAMES; Geoff STEELE - Web page: https://patentgrep.com/patent/US20080185141A1 ## CPC - E21B 43/121: {Lifting well fluids (monitoring of down-hole pump systems E21B47/008)} - F04B 47/12: having free plunger lifting the fluid to the surface - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) ## Abstract An intermittent lift plunger includes at least one seal mandrel, a bottom sub and an upper valve assembly. The valve assembly is closed by a well bottom stop which inserts into the lift plunger and opened by a lubricator stop at the top of the well. The seal mandrel includes a sleeve seal formed from an elastomeric rubber or plastic, which inflates to engage the well bore surface when the valve is closed and a pressure differential exists. ## Claims ### Claim 1 A plunger having an upper end and a lower end, and defining an internal chamber, for intermittently lifting fluids from a well having a bottom well stop means, said plunger comprising: (a) at least one hollow cylindrical seal mandrel disposed between the upper end and lower end, wherein the seal mandrel defines a plurality of openings; (b) a resilient seal sleeve attached to the seal mandrel in a fluid-tight manner, covering the seal mandrel openings; (c) a valve assembly disposed at one end of the plunger, comprising a valve body defining a valve opening, a valve stem wherein the valve is slidingly disposed within the valve body, and is moveable between a first position wherein the valve opening is closed and a second position wherein the valve opening is open; and (d) means for maintaining the valve in an open position, and means for maintaining the valve in a closed position, wherein the force required to overcome the open position means, thereby closing the valve, is less than the force required to overcome the closed position means, thereby opening the valve. ### Claim 2 (depends on 1) The plunger of claim 1 wherein the open position means comprises a ball detent system which cooperates with an upper detent profile formed on the valve stem, and the closed position means comprises a ball detent system which cooperates with a lower detent profile formed on the valve stem, wherein each ball detent comprises a ball biased in an inward radial direction by a spring, said ball cooperating with the corresponding detent profile to resist vertical movement of the valve stem. ### Claim 3 (depends on 1) The plunger of claim 1 wherein the resilient seal sleeve comprises a middle portion disposed between an upper portion and a lower portion, wherein the middle portion is more pliable than one or both of the upper and lower portions. ### Claim 4 (depends on 2) The plunger of claim 2 comprising at least two seal mandrels each having a resilient seal sleeve and joined by a coupler. ### Claim 5 (depends on 2) The plunger of claim 2 wherein the open position ball detent system has fewer detent balls than the closed position detent system. ### Claim 6 (depends on 1) The plunger of claim 1 wherein the valve assembly further comprises a valve actuator assembly comprising: (a) a limiting sleeve disposed within the valve body and which engages an upper end of the valve stem; (b) an actuator sleeve which slidingly engages the limiting sleeve within the valve body and is moveable between a first position extending out of the valve body, and a second position retracted within the valve body; and (c) means for biasing the actuator sleeve away from the valve stem. ### Claim 7 (depends on 1) The plunger of claim 1 wherein the valve body has an exterior surface which functions as a fish neck. ### Claim 8 (depends on 1) The plunger of claim 1 wherein the valve stem is centralized by a valve retainer at a lower end of the valve stem, and by the valve body at an upper end of the valve stem. ### Claim 9 (depends on 5) The plunger of claim 5 wherein the biasing means comprises a valve spring. ### Claim 10 A plunger having an upper end and a lower end, and defining an internal chamber, for intermittently lifting fluids from a well having a bottom well stop means, said plunger comprising: (a) at least one hollow cylindrical seal mandrel disposed between the upper end and lower end, wherein the seal mandrel defines a plurality of openings; (b) a resilient seal sleeve attached to the seal mandrel in a fluid-tight manner, covering the seal mandrel openings, wherein said seal sleeve has a middle portion bounded by an upper portion and a lower portion, wherein the middle portion is more pliable than one or both of the upper portion and lower portion; (c) a valve assembly disposed at one end of the plunger, comprising a valve body defining a valve opening, a valve stem wherein the valve is slidingly disposed within the valve body, and is moveable between a first position wherein the valve opening is closed and a second position wherein the valve opening is open. ### Claim 11 (depends on 10) The plunger of claim 10 wherein the middle portion has an outside diameter closely matching an inside diameter of a tubular within which the plunger travels.