Patent Description:
This invention relates to subsea operations in general and, more specifically, to pressure boosting and regulation of subsea systems and operations.

Subsea hydraulic systems may utilize accumulators to receive and dispense volumes of hydraulic fluid to aid in maintaining proper volume and pressure for various hydraulic circuits. For an accumulator to be useful for delivering pressure and fluid to a circuit it must be charged at a fluid and pressure level that is higher than that normally needed by the circuit.

Pressures needed to charge an accumulator can exceed nominal operating pressure of certain lines and equipment. On the other hand, it can be difficult, if not impossible, to provide outside or remote power to a pump or other device needed to increase hydraulic pressure at or near an accumulator for charging.

What is needed is a system and method for addressing the above and related issues. <CIT> discloses a fluid pressure increasing/decreasing machine that can continuously supply an output pressure to a destination of supply by converting an input pressure from a source of supply. A control device selects at least one input pressure chamber and at least one output pressure chamber from among at least three pressure chambers in a fluid pressure cylinder or a plurality of fluid pressure cylinders operating inter-connectedly, the input pressure chamber being supplied with the input pressure, the output pressure chamber creating the output pressure including a pressure higher than the input pressure and a pressure lower than the input pressure. A flow control valve causes the selected input pressure chamber to communicate with the source of supply, and the selected output pressure chamber to communicate with the destination of supply. At least one of the pressure chambers is capable of being either of the input pressure chamber and the output pressure chamber. <CIT> discloses a hydraulic system that has pressure intensifier that is located to increase actuation pressure for predetermined load above the system pressure acted upon pressure reducing valve. The pressure intensifier is connected with shift element that is arranged between the combustion engine and the electric machine of hybrid gear box. <CIT> discloses a hydraulically or pneumatically actuated piston drive with a reciprocating movement, and more particularly to a double acting booster in which the movements of the low pressure piston influence in the end positions the control pressure for the reverse operation.

Aspects of the present invention are set out in the independent claims.

With reference now to the <FIG>, a perspective view of one embodiment of a physical packaging or configuration of a subsea pressure boosting and regulating system <NUM> is shown. According to various embodiments, the system <NUM> as a unit is fully hydraulic, meaning there are no electrical signals or connections needed. Once fluid is supplied to the inlet or consumed from the outlet, the system <NUM> will begin to operate until a system equilibrium is created. Also, according to various embodiments, the system <NUM> can be retrofitted to any blow out preventer (BOP) system without modifications. In various embodiments explained further below, the system <NUM> bolts on and connects to a hydraulically system with only three hoses (e.g., supply, accumulator, and regulated output). The system <NUM> does not require real-time control, and provides fully redundant intensifiers and regulators.

The physical appearance of the system <NUM> may vary, and <FIG> is only an example. The system <NUM> comprises a hydraulic circuit <NUM>, the function of which is explained in greater detail below, but may take on a variety of external appearances. Control or operation of the system <NUM> may be by a plurality of externally operated ball valves. These provide external switches that are operated by remotely operated subsea vehicles. Accordingly, an actuator <NUM> is provided for operation of ball valve BV1; actuator <NUM> is provided for operation of ball valve BV2; actuator <NUM> is provided for operation of ball valve BV3; actuator <NUM> is provided for operation of ball valve BV4, and actuator <NUM> is provided for operation of ball valve BV5 (BV1, BV2, BV3, BV4, and BV5 shown in <FIG>).

Vent outputs can also be seen in <FIG>. These may include regulator valve A vent <NUM>; intensifier A vent <NUM>; intensifier B vent <NUM>; and regulator valve B vent <NUM>. A gauge panel <NUM> may also be provided and may provide gauges for regulator pressure <NUM>; supply pressure <NUM>; accumulator pressure <NUM> and others. Physically, the system <NUM> may be attached to a frame <NUM> including all necessary lift and support points to allow for subsea installation and operation but remote operated vehicle or otherwise.

In some embodiments, the subsea hydraulic boosting and regulator system (BARS) <NUM> of the present invention is close-coupled to associated subsea accumulators. The subsea BARS <NUM> boosts the pressure of flow that is incoming to the accumulators. When the accumulators must deliver flow to other subsea functions, the subsea BARS regulate the outgoing flow to a tolerable pressure level. In some embodiments, the subsea BARS has no electronics and functions automatically.

Referring now to <FIG> is a hydraulic schematic diagram of a subsea pressure boosting and regulating system according to aspects of the present invention is shown. The circuit <NUM> corresponds to a circuit implemented in the physical BARS packaging of <FIG>. In various embodiments, an intended purpose of the illustrated BARS circuit <NUM> is to increase pressure in subsea accumulators, without the need to increase the pressure ratings of the existing appurtenant subsea piping and subsea hydraulic control systems.

Flow rates and pressures may be engineered or tailored to specific requirements of the system in which the BARS is deployed. Specific pressures, flow rates, and other parameters correspond to specific embodiments, but the present invention is not limited to the same. For example, in one embodiment, a BARS of the present invention faces an incoming supply <NUM> from the surface that has a maximum flow rate of <NUM>/s (<NUM> GPM) and a max pressure of <NUM> MPa (<NUM> PSI). An outgoing un-boosted supply from BARS to subsea accumulators may also have a maximum flow rate of <NUM>/s (<NUM> GPM) and a maximum pressure of <NUM> MPa (<NUM> PSI). Outgoing, boosted supply from BARS to subsea accumulators may have a maximum flow rate of <NUM><NUM>/s (<NUM> GPM) with a maximum pressure of <NUM> MPa (<NUM> PSI). The connection to the accumulators is shown at connection <NUM> (whether boosted or in bypass mode). Incoming supply from the subsea accumulators (also at connection <NUM>) to BARS may be up to a maximum of <NUM>/s (<NUM> GPM) with a maximum pressure of <NUM> MPa (<NUM> PSI).

Regulated output from the BARS to subsea functions at connection <NUM> may have a maximum flow of <NUM>/s (<NUM> GPM) or more and a regulated pressure setpoint at <NUM> MPa (<NUM> PSI) or another selected pressure. This would presume that the associated subsea accumulators are rated to at least <NUM> MPa. (<NUM> PSI). Parameters of the BARS may be set differently for systems having different capabilities. The BARS system itself may operate in high pressure (deep) environments having ambient pressures of from <NUM> to <NUM> MPa (<NUM> to <NUM> PSIG).

Regulating functions of the BARS hydraulic circuit <NUM> is completely redundant. One of at least two regulators, regulator valve A <NUM> and regulator valve B <NUM>, is selectable by ball valves BV3, BV4, respectively. Boosting functions of the BARS hydraulic circuit <NUM> is also completely redundant. One of at least two intensifiers, intensifier valve A <NUM> and intensifier valve B <NUM>, may be selectable by ball valves BV1, BV2, respectively. The boosting functions of the BARS hydraulic circuit <NUM> may also be able to be fully bypassed (e.g., via ball valve BV5).

Referring now <FIG>, a hydraulic schematic diagram of an intensifier <NUM> for use with a subsea pressure boosting and regulating system according to aspects of the present invention is shown. Although intensifier <NUM> is illustrated and discussed in detail, it should be understood that additional intensifiers included in the system <NUM> may operate in an identical way (e.g., intensifier <NUM>). The intensifier <NUM> may be unpowered (apart from the input hydraulic pressure). It is considered to be a double-acting intensifier. Two strokes may provide power via a reciprocating piston arrangement.

Diagrammatically, a piston <NUM> may be considered as viewed in cutaway within the circuit <NUM>. Low pressures are applied to a large surface area to provide high pressure on an associated smaller surface area. A two-sided anulus may provide a larger surface to be pressured by lower pressures and a double ended output ram may be used to create the associated higher pressures. Accordingly, piston <NUM> provides large surface areas <NUM>, <NUM> to which relatively lower pressures are applied (e.g., such as <NUM> MPa (<NUM> PSI) supply) that result in relatively higher pressures (e.g., <NUM> MPa (<NUM> PSI) accumulator pressure) at respective smaller surface areas <NUM>, <NUM>. The area difference between area <NUM> and <NUM>, or <NUM> and <NUM>, may be referred to as the intensification ratio of the intensifier <NUM>.

A portion, or portions, of the piston <NUM> may actuate various valves at various positions within its reciprocating stroke to effect continual operation (e.g., periodic reversal) of the piston <NUM> boosting operations are needed based on pressures of the system (e.g., accumulator pressure of less than <NUM> MPa (<NUM> PSI) and adequate supply pressure is present).

In order for an intensifier to be fully operational, the piston <NUM> must be able to start operation from any stopped position. Thus, a starting point of a piston cycle may be defined with the piston <NUM> somewhere in a middle position of the stroke, with pressure (e.g., supply pressure) being applied for the first time. The instant pressure and flow are available at the inlet (e.g., supply <NUM>), the intensifier <NUM> automatically begins to cycle. The opposite is true when flow is stopped by shutting off the supply <NUM> to the intensifier <NUM>. This causes the intensifier <NUM> to stop cycling and check valves (CV1A, CV1B, CV2A, CV2B) on the outlet will prevent high pressure from back feeding into the supply or vent circuits.

As noted, the stroke of the intensifier piston <NUM> is in two directions. While the E side <NUM> of the piston <NUM> is pressurized, control valves V3, V4 are in a spring offset position. This forces the intensifier <NUM> to always start with E region pressurized (area <NUM> of piston <NUM>) and move towards valves V1 and V2 when started. Initially, supply pressure begins to fill the circuit via CV3A, CV3B, CV4A, and CV4B, which allow ends <NUM>, <NUM> of piston <NUM> to be filled. Being that V4 is spring offset, E region is also filled through and D is vented through vent <NUM>.

The filling of H and E creates a bias force towards V1 and V2 of the piston <NUM>. Fluid can enter the low-pressure end of the piston through CV4A and CV4B. As the piston <NUM> moves, fluid is vented through V3 and CV2A and CV2B which keeps the piston from being hydraulically locked. Resistance to flow on the outlet allows pressure to build on the end of the piston <NUM> in region H (surface <NUM>).

Once the piston <NUM> contacts valve V2 it is shut. This blocks the path for B to vent through V2. As the piston <NUM> moves past V2, it then activates V1. Once open, V1 connects supply <NUM> to F, through V7 into C and builds pilot pressure on V3. Once pressure has raised high enough to pilot V3, V3 connects supply <NUM> to D and begins to build pressure in the pilot of V4 and the annulus area <NUM> of the piston <NUM>. D pressure also holds V8 in the piloted position. When V4 pilot builds high enough to shift, E is then connected to vent <NUM>. This drops the pressure in the annulus area <NUM> of the piston <NUM> creates a bias force in the opposite direction (toward area <NUM>). Fluid is allowed to fill the low-pressure end of the piston <NUM> through CV3A and CV3B. Fluid exits the high-pressure end of the piston through CV1A and CV1B.

When the piston <NUM> has moved far enough to contact and shift V7 it shuts the valve and stops F from filling C. As the piston <NUM> travels further, it contacts and shifts V8 which vents C. When C pressure falls, it allows V3 to spring return and vent D. When D vents, it allows V4 to spring return. Once spring returned, E is connected to supply, filling the E annulus area (at area <NUM>). V3 connects D to vent which drops the pressure on the D annulus area (area <NUM>). This creates a bias force driving the piston <NUM> towards V1 and V2. As the piston <NUM> moves this direction, it will no longer activate V1 but E pressure will hold that valve in the shifted position during the stroke. V7 is allowed to fully spring return as the piston <NUM> moves past it. As the piston <NUM> moves, fluid from D is displaced to vent <NUM>, and intensified pressure can be created in region H on the end <NUM> of the piston <NUM>. Fluid escapes this region and exits the intensifier <NUM> through CV2A and CV2B to accumulator line <NUM>.

Note that an additional bias may be applied to V8 when V3 has shifted to provide supply pressure to D. Thus, V8 is not inadvertently piloted before contact with piston <NUM>. Similarly, an additional bias maybe applied to V1 when V4 provides supply pressure to E to prevent piloting of V1 prior to contact by piston <NUM>.

Referring now to <FIG> is a side cutaway view of the intensifier piston <NUM> for use with the circuit of <FIG> is shown. The piston <NUM> provides one example of a piston that works within the circuit of intensifier <NUM> but other physical arrangements may be workable as well. <FIG> further illustrates the piston <NUM> operating within a void inside a casing or manifold <NUM> that may contain other operations components and portions of the intensifier such as valves V2, V2, V7, and V8. Stroke of the piston <NUM> (left and right, as illustrated) actuates V2, V2, V7, and V8 by displacement of internal stems and poppets as the piston <NUM> moves as described above. Pressure of supply fluid on area <NUM> and <NUM> inside the casing <NUM> acts to create the higher pressures on areas <NUM>, <NUM> within casing <NUM> as described above. Wear resistant rings <NUM> may be provided on the piston <NUM> where it contacts or actuates valves.

In order for intensifiers such as intensifier <NUM> and others within the system <NUM> to operate property, certain two position, three-way valves must have low leakage rates and near zero cross over (i.e., a point during switching when supply, function, and vent ports are all connected). According to various embodiments, valves V1, V2, V7, and V8 are of this type, as explained herein. Referring now to <FIG>, a side cutaway view of a normally open three-way valve <NUM> for use with an intensifier according to the present invention shown. Such valve is suitable for use as valve V3 orV4.

The valve <NUM> comprises a body <NUM> providing a pilot port <NUM>, a vent port <NUM>, a function port <NUM>, and a supply port <NUM>. The body <NUM> can comprise multiple pieces such as sleeve <NUM>, sleeve plug <NUM> and a spool stop <NUM>. Internally, the valve <NUM> comprises an upper spool <NUM> and a lower spool <NUM>. The upper spool <NUM> may be a hollow component having an upper port <NUM> and a lower port <NUM>. Within the hollow upper spool <NUM>, between the upper port <NUM> and lower port <NUM>, a seat <NUM> may be defined that faces downward or toward the lower spool <NUM>.

The lower spool <NUM> may comprise an upper stem <NUM> and a lower stem <NUM>. Lower stem <NUM> may have a fluted or inletted lower portion <NUM> and an upper non-inletted portion <NUM> sized to fit tightly in the seat insert <NUM>. A medial portion <NUM> of the lower spool <NUM> may interpose the upper stem <NUM> and lower stem <NUM>. The medial portion <NUM> may define an upper shoulder <NUM> selectively acting as a sealing surface on seat <NUM> or upper spool <NUM>. A lower shoulder <NUM> may selectively act as a sealing surface on an upward facing seat outer seat <NUM> on a seat insert <NUM> held rigidly in a predetermined position with respect to the body <NUM>. The upper stem <NUM> is sized to fit within the upper spool <NUM> but allow fluid flow, while the medial portion <NUM> and lower stem <NUM> may be sized to selectively block fluid flow at the seat <NUM> or the seat insert <NUM>.

A pilot spool <NUM> may be provided at the pilot port <NUM> rigidly affixed to the lower stem <NUM> of the lower spool <NUM>. The pilot spool <NUM> actuates the valve <NUM> via transmitting forces to the lower spool <NUM>. The lower spool <NUM> is spring-biased downward (toward the pilot spool <NUM>) by a spring follower <NUM> acted upon by an inner spring <NUM> in contact with the sleeve plug <NUM>. The upper spool <NUM> is also biased downward by an outer spring <NUM> in contact with the sleeve plug <NUM>.

In the illustrated closed position, the upper spool <NUM> may be held in correct position by the outer spring <NUM> and by contact with the seat insert <NUM> proximate the medial portion <NUM> of lower spool <NUM>. Lower spool <NUM> is held in position by inner spring <NUM> and contact between the lower shoulder <NUM> and the seat insert <NUM> at seat <NUM>. In this position, being normally open, the valve <NUM> provides for fluid connection between supply port <NUM> and function port <NUM>. The fluid pathway is in through supply port <NUM> and from there through the upper port <NUM> of upper spool <NUM> and inside the spool <NUM>. From there the path is out the lower port <NUM> of the upper spool <NUM> and out the function port <NUM>. Fluid is prevented from leaking to the vent port <NUM> by the medial portion <NUM> of the lower spool <NUM> in contact with the upper spool <NUM>, the contact between the upper spool <NUM> and the seat insert <NUM>, and the contact between the lower shoulder <NUM> and the seat <NUM>.

In operation, with pressure applied to the pilot spool <NUM> the lower spool <NUM> move against the inner spring <NUM> and small distance. Though the lower spool <NUM> becomes unseated, fluid flow to the vent port <NUM> remains minimal owing to a tight tolerance where the lower stem <NUM> passes through the seat insert <NUM> at a the non-inletted portion <NUM>.

The upper shoulder <NUM> of the lower spool <NUM> is further pushed into contact with the seat <NUM> in the upper spool <NUM> which blocks the connection between ports supply port <NUM> and function port <NUM> by closing upper spool <NUM> internally. At this point, all ports of the valve <NUM> are considered blocked. As lower spool <NUM> and upper spool <NUM> now continue to move upward (against springs <NUM>, <NUM>) a flow path is opened between ports function port <NUM> and vent port <NUM> when the fluted or inletted portion <NUM> of lower stem <NUM> moves through the seat insert <NUM>. The valve <NUM> is fully piloted when either spring <NUM> or <NUM> is fully compressed or the spring follower <NUM> comes into contact with the sleeve plug <NUM>. When spring returning, the same sequence of events happens, but in reverse of the piloted direction.

A valve may be changed from normally open to normally closed by, for example, changing the ports used as vent and supply. However, in order to achieve the low leakage and crossover needed for certain application, additional modifications may be needed. Referring now to <FIG> a side cutaway view of a normally closed three-way valve <NUM> for use with an intensifier according to the present invention is shown. The valve <NUM> is suitable for use as the valves V3 or V4. The valve <NUM> shares many components with the valve <NUM> discussed above. In addition to the location of the vent port <NUM> and the supply port <NUM> being exchanged, an upper spool <NUM> and lower spool <NUM> are configured somewhat differently as well.

Here the upper spool <NUM> comprises a hollow or tubular member having an upper port <NUM> allowing fluid flow between outside and inside the upper spool <NUM>. An open bottom end of the upper spool <NUM> defines a lower port <NUM>. A seal or seating surface <NUM> may be configured to selectively seal against a portion of the lower spool <NUM>.

The lower spool <NUM> comprises an upper stem <NUM> that extends into the upper spool <NUM> and contacts the spring follow <NUM> engaging the inner spring <NUM>. The upper stem <NUM> is sized to allow fluid communication through the upper spool <NUM>. A medial portion <NUM> of the lower spool <NUM> defines a cupped seat <NUM> that selectively engages against the seal <NUM> of the upper spool <NUM> to block fluid flow through the upper spool. The cupped seat <NUM> may be concave to accept and circumscribe the lower port <NUM> of the upper spool <NUM>. When moved away from the upper spool <NUM> (spring return position) the cupped seat <NUM> seals against the seat insert <NUM> blocking fluid from the supply port <NUM>. A lower shoulder <NUM> of the seat <NUM> may be shaped to seal against seat <NUM> of seat insert <NUM> to this effect.

In the return position, as illustrated, vent port <NUM> is in fluid communication with upper port <NUM> of the upper spool <NUM> and thus to the interior of the upper spool <NUM>. The cupped seat <NUM> is backed off from the lower port <NUM> which thereby communicates to function port <NUM>. When piloted the cupped seat <NUM> moves to engage against lower port <NUM> of upper spool <NUM>. This blocks the path between vent port <NUM> and function port <NUM>. Fluid flow between function port <NUM> and supply port <NUM> initially remains blocked by a tight fit between a non-inletted upper portion <NUM> of a lower stem <NUM> of the lower spool <NUM> remaining within the seat insert <NUM>. However, as a lower inletted or fluted portion <NUM> of the lower stem <NUM> moves into the seat insert <NUM> a fluid pathway is opened between function port <NUM> and supply port <NUM>.

Again, the upper spool <NUM> is biased by outer spring <NUM> and the lower spool <NUM> is separately biased by inner spring <NUM>. When either of these springs <NUM>, <NUM> are fully compressed or the spring follower <NUM> contacts the sleeve plug <NUM> the valve <NUM> is fully piloted. When moving to a spring return position, the sequence of events is reversed with the upper spool <NUM> and lower spool <NUM> initially moving together such that vent port <NUM> remains blocked until function port <NUM> has been blocked by lower spool <NUM>, at which point the lower spool <NUM> extends further separating the cupped seat <NUM> from lower port <NUM> of the upper spool <NUM> and restoring the fluid path between vent port <NUM> and function port <NUM>.

As discussed above, an additional function of the BARS system <NUM> is to provide regulated pressure as an output. The regulators <NUM>, <NUM> may comprise regulation systems as are known in the art and which may be suitable or may be made suitable for the environment and operational parameters of the system <NUM>. However, regulators <NUM>, <NUM> may also comprise a regulator constructed in accordance with various embodiments of the present disclosure. Referring now to <FIG> a side cutaway view of a regulator <NUM> according to aspects of the present disclosure is shown. The regulator <NUM> is suitable for use within or as the regulator <NUM>, <NUM> of the present invention.

A manual version of regulator <NUM> functions by having a spring <NUM> which creates a bias force for a pilot regulator <NUM>. The spring force and ultimately the regulator set pressure can be manually changed by using screw mechanism <NUM> to compress or decompress the spring <NUM>. In some embodiments, a housing <NUM> that contains the spring <NUM> is altered to allow a hydraulic connection to apply pressure rather than using a spring <NUM> to create the bias force on the pilot regulator <NUM>. However, the basic regulator (<NUM>) design remains the same between these two implementations.

The pilot regulator <NUM> is housed in pilot housing <NUM>. The spring <NUM> (or other pressure bias force) is transferred to top pilot member <NUM> which pushes on middle pilot member <NUM>. Middle pilot member <NUM> defines an interior opening communicating to an interior opening on a lower pilot member <NUM>. The middle pilot member <NUM> has a nose <NUM> opposite the lower pilot member <NUM> that selectively engages with a top pilot member <NUM>. Top pilot member <NUM> defines an interior passage opening to middle pilot member <NUM> that is also closed on an opposite end. However, a radial passageway <NUM> leads from within the top pilot member <NUM> to the outside of the top pilot member <NUM>. The housing <NUM> also provides a radial passage <NUM> at the bottom (left), below the bottom pilot member <NUM>, a radial passageway <NUM> on a medial portion leading to outside the middle pilot member <NUM>, and an upper radial passageway <NUM> leading to outside the upper pilot member <NUM>. In some embodiments, passageway <NUM> provides supply pressure and passageway <NUM> provides vent.

The nose <NUM> of middle pilot member <NUM>, when seated against top pilot member <NUM>, blocks the interior passageway of the top pilot member <NUM>. However, the nose <NUM> defines one or more lateral passageways that allows for fluid communication from within the middle pilot member <NUM> to inside top pilot member <NUM> when the two are separated.

Middle pilot member <NUM> has a seat on pilot housing <NUM> which makes a seal and prevents middle pilot member <NUM> from pushing upward (right in the drawing) on top pilot member <NUM>. An outer surface of top pilot member <NUM> is exposed to supply pressure.

When the system <NUM> is at low pressure, there will be minimal pressure inside of middle pilot member <NUM>. Without pressure internal to middle pilot member <NUM>, the spring force pushing on top pilot member <NUM> will unseat middle pilot member <NUM> from the pilot housing <NUM> (moving it leftward as shown) and allow pressure to fill pilot region <NUM> of a main stage regulator <NUM>. It will also fill the regulated port <NUM> through the check valve assembly <NUM> and orifice <NUM> until both the regulated and pilot pressure rise.

It is important to note that due to the large force on upper pilot member <NUM> from the spring <NUM> (or hydraulic pressure), upper pilot member <NUM> and middle pilot member <NUM> make a seal and move together. Once the pressure in the pilot region <NUM> starts to build, it begins to create a resulting force on middle pilot member <NUM>. This in turn pushes on the spring <NUM> (or the hydraulic pressure), and begins to balance out the bias force. Once the pressure in pilot region <NUM> is high enough to nearly match the bias force, a spring <NUM> will provides enough force to push middle pilot member <NUM> into contact against the seat of pilot housing <NUM> and create a seal. This blocks supply pressure from raising the pressure in the pilot region <NUM>. Should the pilot pressure be high enough to create more force on middle pilot member <NUM> than the bias force can offset, it will separate middle pilot member <NUM> and upper pilot member <NUM> and allow pressure in the pilot region to escape out the passageways of <NUM> and out vent port <NUM> of the regulator <NUM>.

The pressure on the pilot region <NUM> is thus maintained by the pilot regulator <NUM> as described above. The main stage <NUM> of the regulator <NUM> is designed to use this pilot pressure as a reference pressure which creates the "set point" at which the regulator tries to maintain during operation. This is accomplished by having the pilot pressure push on spool <NUM> slidable within sleeve <NUM>. Being that valve <NUM> is affixed attached to spool <NUM>, pilot pressure may overcome the force created by spring <NUM> and spring follower <NUM>, as well as a pressure in the regulated port <NUM> that is too low to offset the force created by the pilot. This causes valve <NUM> to push away from valve seat <NUM> on sleeve <NUM>, breaking the seal made by the contact between these two parts. This allows fluid from the supply port <NUM> to move from the outside to the inside of sleeve <NUM>, past valve <NUM>, and out through the regulated port <NUM>.

The shape and design of valve <NUM> is tapered in such a way such that it creates a very dampened flow path with low gain, meaning the flow path is opened gradually. This is especially effective when small flows are required. The geometry also utilizes the flow forces to help "push" valve <NUM> as open as soon possible to create an efficient flow path when a large pressure differentials exists. To this end, the top, or high-pressure side, of valve <NUM> may be dished where it joins spool <NUM>.

On the other hand, orifice <NUM> housed in spring follower <NUM> creates a restriction for the displaced fluid in the spring chamber of spring follower <NUM> when valve <NUM> is forced open quickly by a large pressure differential. This design forces the regulator <NUM> to open slowly, helping to reduce downstream pressure spikes that can cause damage to the system or regulator oscillation.

Due to the fact that spring follower <NUM> is not affixed to spool <NUM> or valve <NUM>, the regulator can "snap" closed and quickly stop the supply pressure from raising the regulated pressure beyond the set point. In the event that the regulated pressure increases above the set point, a relief valve will open and vent off excess pressure. A separate relief valve (not shown) may be used or a relief valve <NUM> may be provided in the spool <NUM> as described below.

It is common for downstream equipment to create pressure spikes in the regulated port <NUM> as well as any unintended leakage across the regulator main stage <NUM>. To protect against over pressurization, the regulated pressure works on the nose area of cup <NUM> (part or relief valve <NUM>) creating an opening force. This opening force is balanced by a spring <NUM> as well as the pilot pressure. When the pressure in the regulated port <NUM> exceeds the pilot pressure by the spring and area ratio of the relief, it will force cup <NUM> open and compress the spring <NUM> until either cup <NUM> bottoms out (right most position, as shown) , or the pressure in the regulated port <NUM> is lowered. When cup <NUM> is forced open by the regulated pressure, this region becomes connected to the vent port <NUM> via ports in spool <NUM>. When the regulated pressure is relieved to a low enough pressure where it can no longer overcome the pilot pressure and the spring <NUM>, the bias force will push cup <NUM> back into a seating edge of spool <NUM> and block the flow path from regulated port <NUM> to vent port <NUM>.

In various embodiments, a meantime between failures (MTBF) of a BARS system, <NUM> must be in the range of <NUM> months of operational subsea usage. Given such an MTBF requirement, the corresponding cycle requirements are estimated as Intensification circuit: <NUM>,<NUM> reciprocating cycles on the intensifier circuit and <NUM>,<NUM> flow events on the regulating circuit. Each regulator may separately meet the MTBF requirements.

Fluid media for the BARS system <NUM> may be of a <NUM>% water, <NUM>% glycol-based additive type. Brands that are suitable may include Brand: Stack Magic™, Erifon™, or others. Cleanliness may be NAS <NUM>.

Some embodiments contain filters at appropriate location. The filters may be provided with a bypass check valve to allow flow if the associated filter becomes clogged. With respect to leakage and consumption of fluid, depending on the needs of the user, incoming supply from surface embodiments of the BARS <NUM> may have <NUM> drops/minute at <NUM> MPa (<NUM> PSI) during standby and a maximum of <NUM>% of incoming flow when an intensifier is in use. Outgoing, boosted supply from BARS <NUM> to subsea accumulators may have <NUM> drops/minute at <NUM> MPa (<NUM> PSI). Incoming supply from subsea accumulators to BARS <NUM> may have a maximum of <NUM> drops/minute at <NUM> MPa (<NUM> PSI). Outgoing, regulated supply from the BARS <NUM> to subsea functions may have a maximum of <NUM> drops/minute at <NUM> MPa (<NUM> PSI). A ratio of the boosted supply from BARS <NUM> to subsea accumulators with respect to the incoming supply from surface may be <NUM>, ±<NUM>%, and may also vary depending on application. A nominal setpoint of the outgoing supply from BARS <NUM> to subsea functions may be <NUM> MPa (<NUM> PSI) and there may be a tolerance on this nominal setpoint of ±<NUM>%. It should be understood that these parameters are with respect to specific embodiments, and do not necessary represent every implementation, or possible implementation, according to the present invention.

Physical dimensions of the BARS <NUM> may vary. In one embodiment a BARS is 610x546x318 mm (24x21.5x12. Weight may be <NUM> (<NUM> pounds). The BARS <NUM> may be designed to operate over a temperature range of -20C to +50C.

In some embodiments, incoming supply from surface may be a <NUM> (<NUM>-<NUM>/<NUM>") type socket weld SAE Code <NUM> design with radial seal in addition to compression face seal. Outgoing, boosted supply from BARS to subsea accumulators / incoming supply from subsea accumulators to BARS may be a <NUM> (<NUM>-<NUM>/<NUM>") type socket weld SAE Code <NUM> design with radial seal in addition to compression face seal. Outgoing, regulated supply from BARS to subsea functions may be a <NUM> (<NUM>-<NUM>/<NUM>") type socket weld SAE Code <NUM> design with radial seal in addition to compression face seal. As with other parameters, these may vary depending upon needs of the end user.

The materials from which the BARS <NUM> is constructed may vary. However, acceptable stainless steel materials may AISI <NUM>, Nitronic <NUM>, Nitronic <NUM>, <NUM> duplex, and/or Inconel <NUM>. <NUM>-<NUM> stainless steel may be used for high strength components if PH1150 heat treated. Internal seals may be suitable for long-term functionality with the relevant hydraulic fluid. In some embodiments, the internal seals may be resilient against occasional exposure to salt water, as well as salt-laden air. In various embodiments all internal seals are suitable for long-term functionality while immersed in salt water, as well as the applicable hydraulic fluid. External seals may also be resilient against occasional exposure to salt-laden air. All materials used on the BARS <NUM> may be subject to the associated MTBF requirements for the device.

It should be understood that a BARS <NUM> according to the present invention may be constructed, manufactured, maintained, etc. in accordance with a wide variety of standards that may be desirable or required in the art. These include, but are not limited to, various API Specifications or standards (Latest Editions) such as API Spec 16D (Specification for Control Systems for Drilling Well Control Equipment and Control Systems for Diverter Equipment; and API Std <NUM> (Blowout Prevention Equipment Systems for Drilling Wells). Latest editions of ASTM specifications may also be implemented including, but not limited to: A370 (Standard Test Methods and Definitions for Mechanical Testing of Steel Products); A751 (Test Methods Practice and Terminology for Chemical Analysis of Steel Products); A314 (Nitronic <NUM> (XM-<NUM>), Nitronic <NUM> (Alloy <NUM>)); E23 (Standard Test Methods for Notched Bar Impact Testing of Metallic Materials); and E709 (Standard Guide for Magnetic Particle Examination). Various ANSI/ASME Specifications (Latest Editions) may also be implemented, including, but not limited to: B21/B21M-<NUM> (Standard Specification for Naval Brass Rod, Bar, and Shapes); and AISI <NUM> (Stainless Steel).

It is to be understood that the terms "including", "comprising", "consisting" and grammatical variants thereof do not preclude the addition of one or more components, features, steps, or integers or groups thereof and that the terms are to be construed as specifying components, features, steps or integers.

It is to be understood that where the claims or specification refer to "a" or "an" element, such reference is not be construed that there is only one of that element.

It is to be understood that where the specification states that a component, feature, structure, or characteristic "may", "might", "can" or "could" be included, that particular component, feature, structure, or characteristic is not required to be included.

Where applicable, although state diagrams, flow diagrams or both may be used to describe embodiments, the invention is not limited to those diagrams or to the corresponding descriptions. For example, flow need not move through each illustrated box or state, or in exactly the same order as illustrated and described.

Methods of the present invention may be implemented by performing or completing manually, automatically, or a combination thereof, selected steps or tasks.

The term "method" may refer to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the art to which the invention belongs.

The term "at least" followed by a number is used herein to denote the start of a range beginning with that number (which may be a ranger having an upper limit or no upper limit, depending on the variable being defined). For example, "at least <NUM>" means <NUM> or more than <NUM>. The term "at most" followed by a number is used herein to denote the end of a range ending with that number (which may be a range having <NUM> or <NUM> as its lower limit, or a range having no lower limit, depending upon the variable being defined). For example, "at most <NUM>" means <NUM> or less than <NUM>, and "at most <NUM>%" means <NUM>% or less than <NUM>%.

When, in this document, a range is given as "(a first number) to (a second number)" or "(a first number) - (a second number)", this means a range whose lower limit is the first number and whose upper limit is the second number. For example, <NUM> to <NUM> should be interpreted to mean a range whose lower limit is <NUM> and whose upper limit is <NUM>. Additionally, it should be noted that where a range is given, every possible subrange or interval within that range is also specifically intended unless the context indicates to the contrary. For example, if the specification indicates a range of <NUM> to <NUM> such range is also intended to include subranges such as <NUM> -<NUM>, <NUM>-<NUM>, etc., <NUM>-<NUM>, <NUM>-<NUM>, etc., as well as any other possible combination of lower and upper values within the stated range, e.g., <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, etc. Note that integer range values have been used in this paragraph for purposes of illustration only and decimal and fractional values (e.g., <NUM> - <NUM>) should also be understood to be intended as possible subrange endpoints unless specifically excluded.

It should be noted that where reference is made herein to a method comprising two or more defined steps, the defined steps can be carried out in any order or simultaneously (except where context excludes that possibility), and the method can also include one or more other steps which are carried out before any of the defined steps, between two of the defined steps, or after all of the defined steps (except where context excludes that possibility).

Further, it should be noted that terms of approximation (e.g., "about", "substantially", "approximately", etc.) are to be interpreted according to their ordinary and customary meanings as used in the associated art unless indicated otherwise herein. Absent a specific definition within this disclosure, and absent ordinary and customary usage in the associated art, such terms should be interpreted to be plus or minus <NUM>% of the base value.

Claim 1:
A system (<NUM>) comprising:
at least one hydraulic intensifier circuit (<NUM>) accepting a supply pressure and returning a boosted pressure that is higher than the supply pressure wherein the hydraulic intensifier circuit further comprises:
a reciprocating piston (<NUM>) having a first side and an opposed second side, each of the first and second side having a larger low-pressure region (<NUM>; <NUM>) and a smaller high pressure region (<NUM>; <NUM>);
a first three-way control valve (V4) selecting for supply pressure or vent to the first side low pressure region of the reciprocating piston; and
a second three-way control valve (V3) selecting for supply pressure or vent to the second side low pressure region of the reciprocating piston,
wherein a low pressure applied to the first side low pressure region moves the piston to create a high pressure on the second side high pressure region, and
wherein the low pressure applied to the second side low pressure region moves the piston to create the high pressure on the first side high pressure region,
wherein the second three-way control valve pilots the first three-way control valve, and
characterized in that the piston, when making a first movement toward the second side closes a first two-way valve (V2) thereby blocking vent to a pilot port of the second control valve, and preferably
wherein the piston, when making a second further movement toward the second side opens a second two-way valve (V1) thereby providing supply pressure to the pilot port of the second control valve, and further characterized by
at least one regulator (<NUM>) that accepts the boosted pressure and returns a regulated lower, regulated pressure that is lower than the boosted pressure.