US 6,684,897 B2 · Valve actuator and method

Abstract

A subsea actuator and method is disclosed that includes all moving components mounted in a compact, concentric configuration. The subsea actuator is highly reliable and will operate at depth even with zero valve body cavity pressure. A preferably cup-shaped spring pusher is provided in telescoping relationship to the hydraulic chamber. A piston position indicator is provided which is connected externally to the hydraulic piston cylinder to avoid the possibility of hydraulic leaks due to the piston indicator. A manual override may be provided with a manual override indicator. The manual override indicator has a shorter travel length than the manual override operating stem to thereby reduce the overall length of the manual override assembly. The driving stem provides a removable connection to the hydraulic piston from the top of the actuator housing and a quick disconnect permits disconnection of the driving stem from the valve stem. In a preferred embodiment, upper and lower t-slot connections are utilized in the driving stem assembly. In a preferred embodiment, two back seat valves are removably secured to the driving stem to engage respective seats and provide additional sealing around the driving stem so as to prevent leakage between the valve chamber and actuator housing chamber. The high tension spring does not need to be removed to perform maintenance, and all wear items and seals are readily accessible. Change or replacement of the stem packing is made from the top of the bonnet to avoid dissasembling the bonnet to valve body connection. Pre-load bolts are used to adjustably preload the tension in the return spring. The height/weight of the actuator is significantly reduced as compared to prior art subsea valve actuators.

Drawings

Claims35

Dependent claims

A method for preventing leakage between an actuator and a gate valve wherein an actuator shaft is reciprocally moveable for operating said gate valve, said method comprising:

mounting a first actuator shaft valve member in surrounding relationship to said actuator shaft for movement therewith;
providing a first scat in surrounding relationship to said actuator stem;
and
engaging said first actuator shaft valve member with said first scat when said actuator shafts moves to a first position so as to prevent leakage around said actuator shaft between said actuator and said gate valve, and disengaging when said actuator shaft moves to a second position;
mounting a second actuator shaft valve member to said actuator shaft for movement therewith, said second actuator shaft valve member being axially spaced from said first actuator shaft valve member along said actuator shaft;
providing a second scat in surrounding relationship to said actuator stem;
and
engaging said second actuator shall valve member with said second seat when said actuator shafts moves to said second position so as to prevent leakage around said actuator shaft between said actuator and said gate valve, and disengaging when said actuator shaft moves to said first position.

5 more elements

A valve actuator for a valve, said actuator comprising:

a hydraulic actuator housing attachable to said valve;
a hydraulic piston slidably mountable within said hydraulic housing responsively to hydraulic pressure, said hydraulic piston being moveable to a first position for closing said valve and to a second position for opening said valve;
a cylinder member defining therein a piston chamber, said hydraulic piston being mounted for movement within said piston chamber, said cylinder member defining a first hydraulic fluid port into said piston chamber on a first side of said piston and a second hydraulic fluid port into said piston chamber on a second side of said piston;
a plurality of seals for limiting movement of hydraulic fluid within said hydraulic actuator housing to said piston chamber and said first hydraulic fluid port and said second hydraulic fluid port;
a manual override assembly for manually operating said hydraulic piston;
and
a return spring chamber within said hydraulic actuator housing, said return spring chamber being fluidly isolated from said piston chamber;
and
a return spring within said return spring chamber such that said return spring is isolated from said hydraulic fluid.

6 more elements

A valve actuator for use with a valve, said valve having a valve body with a valve body cavity therein, a valve body cavity seal for scaling said valve body cavity, said actuator comprising:

a hydraulic actuator housing attachable to said valve;
a hydraulic piston slidably mountable within said hydraulic actuator housing responsively to hydraulic pressure;
an actuator shaft assembly connected with respect to said hydraulic piston and extending into said valve body cavity for operating said valve such that said hydraulic piston is moveable to a first position for closing said valve and to a second position for opening said valve;
and
a first actuator shaft valve member mounted in surrounding relationship to said actuator shaft and extending radially outwardly from said actuator shaft, said first valve member being affixed to said actuator shaft for movement with said actuator shaft;
and
a first seat assembly in surrounding relationship to said actuator shaft and affixed in position with respect to said actuator housing and said valve body, said first actuator shaft valve member being engageable said first seat assembly for sealing around said actuator shaft to provide an additional seal between said hydraulic actuator housing and said valve body when said hydraulic piston is moved to at least one of said first position or said second position, said first actuator shaft valve member being moveable axially away from said first seat assembly so as not to seal with said first seat assembly when said hydraulic piston is moved to the other of said first position or second position, said first seat assembly comprising a replaceable seat removeable from said actuator housing and said valve body.

4 more elements

A valve actuator for use with a valve, said valve having a valve body with a valve body cavity therein, a valve body cavity seal for sealing said valve body cavity, said actuator comprising:

a hydraulic actuator housing attachable to said valve;
a hydraulic piston slidably mountable within said hydraulic actuator housing responsively to hydraulic pressure:
seals for isolating said hydraulic actuator housing from said valve body cavity;
an actuator shaft assembly connected with respect to said hydraulic piston and extending from said hydraulic actuator housing through said seals into said valve body cavity for operating said valve such that said hydraulic piston is moveable to a first position for closing said valve and to a second position for opening said valve;
and
a first actuator shaft valve member mounted to said actuator shaft assembly for movement with said actuator shaft, said first actuator shaft valve member extending radially outwardly from said actuator shaft assembly and being in surrounding relationship to said actuator shaft assembly, said first actuator shaft valve member being mounted to a portion of hydraulic shaft assembly which is always positioned within said hydraulic actuator housing during operation of said valve actuator;
and
a first seat in surrounding relationship to said actuator shaft assembly and being affixedly mounted within said hydraulic actuator housing, said first actuator shaft valve member engaging said first seat for sealing engagement around said actuator shaft assembly when said hydraulic piston is moved to at least one of said first position or said second position to thereby provide an additional seal between said hydraulic actuator housing and said valve body cavity, said first actuator shaft valve member moving axially away from said first seat so as not to seal with said first seat when said hydraulic piston is moved to the other of said first position or second position.

5 more elements

Dependencies are inferred from the claim text.

Description6,385 words

Summary2,734 words

#1. Field of the Invention

#The present invention relates generally to gate valve actuators and, in a particular embodiment, to apparatus and methods for a fail-safe hydraulic subsea actuator that reliably operates in deep water for extended time periods.

#2. Description of the Background

Brief description of the drawings7 figures

#FIG. 1 is an elevational view, partially in section, of a subsea hydraulic actuator assembly mounted to an exemplary valve in accord with the present invention;

#FIG. 2 is an elevational view, partially in section, of a subsea hydraulic actuator assembly in accord with the present invention;

#FIG. 3 is an enlarged elevational view, partially in section, of a hydraulic cylinder configuration in accord with the present invention;

Detailed description3,492 words

#While the present invention will be described in connection with presently preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents included within the spirit of the invention and as defined in the appended claims.

#Referring now to the drawings, and more particularly to FIG. 1, the generally preferred configuration of subsea actuator 10, in accord with the present invention, is illustrated connected to gate valve 12. Various types of gate valves, such as gate valve 12 may be controlled using the actuator of the present invention. Gate valve 12 includes a gate 14 that may be moved between an open position and a closed position as is well known to control fluid flow through passageway or line 16. Gate valve 12 includes gate valve housing 18. Gate valve chamber 20 may be at line pressure sometimes during operation and one object of the present invention is to provide means for preventing leakage between gate valve chamber 20 and actuator housing 22 as is discussed hereinbelow in detail.

#FIG. 2 shows actuator 10 in a somewhat enlarged view. Actuator housing 22 is removably connected to bonnet 24 preferably be means of bolts 26 although other removable fasteners, such as various types of bolts or clamps could also be used.

Facts

Application

10/308,806Filed 3 Dec 2002 · division

Priority

8 Mar 2001

Published

US 2003/0116200 A126 Jun 2003

Granted

3 Feb 2004

Term ended

8 Mar 2021

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification11 codes

F16K 37/0008
Special means in or on valves or other cut-off apparatus for indicating or recording operation thereof, or for enabling an alarm to be given:…
F16K 31/122
Actuated by fluid: the fluid acting on a piston
Y10T 137/0396
Processes: involving pressure control
Y10T 137/0497
Valve or valve element assembling, disassembling, or replacing: fluid actuated or retarded

Family

Application09/802,209Parent of this division · filed 8 Mar 2001

US 2003/0116200 A1Pre-grant publication · published 26 Jun 2003

US 6,609,533 B2Parent of this division · filed 26 Aug 2003

US 2002/0124889 A1Published application

US 6,684,897 B2This patent

From the US filing history. Foreign family members aren’t listed.

Valve actuator and method

Life of this patent

Valve actuator and method

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims35

Description6,385 words

Drawings

Classification11 codes

Life of this patent

Description6,385 words