Patent Description:
Equipment mounted on certain subsea installations are subject to vibration. Vibrations can damage both electronics and mechanical components over time and decrease their service life or even cause failure of the equipment. Vibrations can cause bolts to fail, and welds can suffer fatigue while exposed to vibrations over time. Known elastomeric vibration dampeners are not suitable for subsea applications because the elastomer dissolves in seawater over time. <CIT>) and <CIT>) disclose examples of the related art.

Thus, an object of the present invention is to dampen vibrations emanating from a component to another component mounted thereto.

The above objects are achieved by a subsea equipment assembly comprising a first component having an axis, a second component and an anti-vibration bracket. The anti-vibration bracket is attached to the first component and the second component. In use the first component is caused to vibrate at least in a radial direction relative to the axis. The anti-vibration bracket comprises a plate portion. The plate portion extends at least radially away from the first component and comprises an attachment region located a radial distance away from the first component. The second component is attached to the attachment region. The plate portion comprises an edge having a complementary shape to an outer surface of the first component and including a plurality of notches. Each notch is provided to accommodate a foot secured to the first component. The position of the edge and the attachment region is fixed with respect to one another. The anti-vibration bracket comprises an array of slots.

At least some of the slots of the array of slots are located between the first component and the attachment region.

At least some of the slots of the array of slots may be located radially outwardly of the attachment region.

At least some of the slots of the array of slots may be located to a lateral side of the attachment region.

At least some of the slots of the array of slots may be arranged in at least one row with respect to the radial direction.

At least some of the slots of the array of slots may be arranged in at least two rows with respect to the radial direction.

The array of slots may be arranged such that any radial line passes through at least one of the slots and either a contact point between the anti-vibration bracket and the first component or where the anti-vibration bracket is attached to the first component.

At least some of the slots of the array of slots may be arranged such that their centreline is at an angle to a radial line. The angle may be between -<NUM>° and +<NUM>°, preferably between -<NUM>° and +<NUM>°.

At least some of the slots of the array of slots may be curved. Preferably, at least some of the slots of the array of slots may have a curvature with a constant radius and preferably a radius from the axis.

The anti-vibration bracket may comprise an edge region and none of the slots the array of slots are within the edge region.

At least some of slots of the array of slots may extend through the anti-vibration bracket.

At least some of slots of the array of slots may extend partly through the anti-vibration bracket.

The first component may be a venturi flow meter and the second component may be a differential pressure sensor.

At least some of the slots of the array of slots may have an aspect ratio between and including <NUM> and <NUM>.

A radial line from the axis may pass through the slots.

The slots may be located between the first component and the attachment region.

The above-mentioned attributes and other features and advantages of the present invention and the manner of attaining them will become more apparent and the present technique itself will be better understood by reference to the following description of embodiments of the present technique taken in conjunction with the accompanying drawings, wherein:.

<FIG> are opposing views on a subsea equipment assembly <NUM> comprising a first component <NUM>, in this example a venturi flow meter <NUM>, and a second component <NUM>, in this example a differential pressure sensor <NUM>. The differential pressure sensor <NUM> is mounted to the venturi flow meter <NUM> via an anti-vibration bracket <NUM> and in accordance with the present invention. In this exemplary embodiment of the present invention two differential pressure sensors <NUM> are present. Two differential transducers <NUM> are provided for redundancy purposes. The venturi flow meter <NUM> is located along a pipeline (not shown) and which would be bolted to end flanges <NUM>, <NUM>. The venturi flow meter <NUM> has an axis <NUM> along which a fluid flows in use. In this example, the direction of the flow of fluid in the pipeline and passing through the venturi flow meter <NUM> is from left (upstream) to right (downstream) as shown by the arrow <NUM>. The differential pressure sensor <NUM> is capable of measuring parameters of the fluid flowing through the venturi flow meter <NUM> such as flow rate and pressure within the fluid. Specifically, the differential pressure sensor <NUM> is measuring the differential pressure in the fluid between an inlet diameter and a restriction in the venturi flow meter <NUM> as known in the art.

The fluid passing through the pipeline and venturi flow meter <NUM> may comprise different fluids such as sea water and oil as well as solids such as sands and gravels. The different densities of the fluid and solids cause eccentric forces as the fluid is accelerated and decelerated through the venturi and which generates the vibrations. The vibrations manifest in the radial or Y-direction and axial (<NUM>) or X-direction.

As shown in <FIG> a reference axis is shown with X denoting the direction of the axis <NUM>, Y is the radial direction and Z is a direction perpendicular to X and Z. An axial plane is defined by a plane that is perpendicular to the X direction or the axis <NUM>.

The differential pressure sensor <NUM> is bolted to the anti-vibration bracket <NUM> via an array of bolts <NUM>. The anti-vibration bracket <NUM> is bolted to the venturi flow meter <NUM> and extends radially and in an axial plane with respect to the axis <NUM>. The anti-vibration bracket <NUM> is located at an upstream part of the venturi flow meter <NUM>. At a downstream part of the venturi flow meter <NUM> is located a pair of brackets <NUM>, <NUM>. The brackets <NUM>, <NUM> are bolted to the venturi flow meter <NUM> and extend radially and in an axial plane relative to the axis <NUM>. A guard plate <NUM>, <NUM> is mounted to each one of the brackets <NUM>, <NUM> respectively and to the anti-vibration bracket <NUM>. The guard plates <NUM>, <NUM> protect the subsea equipment assembly <NUM> from damage such as from drag lines or fishing nets. A radially outer part <NUM> of the guard plates <NUM>, <NUM> and a radially outer part <NUM> of the anti-vibration bracket <NUM> are curved such that objects that might otherwise snag are deflected harmlessly over the subsea equipment assembly <NUM>. Depending on the direction cables approach the differential pressure sensor(s) <NUM> for example, the anti-vibration bracket <NUM> may be located at a downstream part of the venturi flow meter <NUM> and the pair of brackets <NUM>, <NUM> are located at an upstream part of the venturi flow meter <NUM>.

Referring now to <FIG> and <FIG> which are views on different embodiments of the anti-vibration bracket <NUM> and which are in accordance with the present invention. In <FIG> and <FIG>, like features are denoted by the same reference numbers. In use, fluid passing through the venturi flow meter <NUM> causes vibrations. Previously, these vibrations can cause damage to components such as the differential pressure sensor <NUM>, welds and bolts of the subsea equipment assembly <NUM>.

The present anti-vibration bracket <NUM> is generally plate-like in form and has a plate portion <NUM> having a thickness. The anti-vibration bracket <NUM> is metallic and preferably a stainless steel, but other metals and alloys may be used and particularly those that are resistant to corrosion in harsh environments such as sea water. The anti-vibration bracket <NUM> comprises an edge <NUM> which is a complementary shape to the outer surface <NUM> (see <FIG>) of the venturi flow meter <NUM>. The edge <NUM> is the radially innermost part of the anti-vibration bracket <NUM> when assembled to the subsea equipment assembly <NUM>. In these embodiments the plate portion <NUM> is arranged in an axial plane relative to the axis <NUM> and therefore extends generally radially outwardly. In other examples, the anti-vibration bracket <NUM> may be arranged such that the plate portion <NUM> is at an angle to the radial direction and the axial plane.

In an assembled state, the edge <NUM> is in contact with the outer surface <NUM> of the venturi flow meter <NUM>, although depending on tolerances or in another embodiment there may be a gap between the edge <NUM> and the outer surface <NUM>. The edge <NUM> comprises a number of notches <NUM> which are provided to accommodate a foot <NUM>. Bolt <NUM> secures the foot <NUM> to the venturi flow meter <NUM> and bolt <NUM> secures the anti-vibration bracket <NUM> and the foot <NUM> together. In this example, a cut-out <NUM> is provided in the edge <NUM> so that the anti-vibration bracket <NUM> avoids contact with a lifting hook (not shown) that is fixed to the venturi flow meter <NUM>. In other examples of the present anti-vibration bracket <NUM> there may be no need for a cut-out <NUM>. Further, other attachment means to the foot <NUM> may be used and therefore in other examples of the anti-vibration bracket <NUM> that are not according to the claimed invention there may be no notches <NUM>.

The plate portion <NUM> comprises an attachment region <NUM> located a radial distance away from the venturi flow meter <NUM>. The differential pressure sensor <NUM> is attached to the attachment region <NUM> via the array of bolts <NUM> (shown in <FIG>). The array of bolts <NUM> engage an array of bolt holes <NUM> provided in the anti-vibration bracket <NUM> and in this example in the plate portion <NUM>. In this example, two arrays of bolts <NUM> and holes <NUM> are provided for the two differential pressure sensors <NUM> seen in <FIG>. It should be appreciated that other attachment means, such as welding, can be used to attach the differential pressure sensors <NUM> to the anti-vibration bracket <NUM>.

The anti-vibration bracket <NUM> comprises an array of slots <NUM> with individual slots denoted by reference <NUM>. At least some of the slots <NUM> are located between the venturi flow meter <NUM> and the attachment region <NUM>. The array of slots <NUM> is arranged such that any radial line, e.g., radial lines <NUM> and <NUM>, passes through at least one of the slots <NUM> and either a contact point <NUM> or an attachment region <NUM> (of the edge <NUM>) between the anti-vibration bracket <NUM> and the venturi flow meter <NUM> or where the anti-vibration bracket <NUM> is attached to the venturi flow meter <NUM>, i.e. an attachment region <NUM> and in this case notch <NUM>. As mentioned previously, the venturi flow meter <NUM> is caused to vibrate predominantly in a radial direction because of the fluid passing therethrough. The vibrations are transmitted through the anti-vibration bracket <NUM> in a radial direction and from or through any point of contact like the contact point <NUM> or attachment region <NUM>. The direct radial path of the vibrations passes through at least one slot <NUM> so that the vibrations cannot pass directly into the attachment region <NUM> and thereby cannot pass directly to the differential pressure sensor <NUM>. The attachment region <NUM> and the differential pressure sensor(s) <NUM> are at least partly isolated from the source of the vibrations emanating into the anti-vibration bracket <NUM>. The array of slots <NUM> provides a region <NUM> that is more flexible or of reduced elastic modulus compared to the plate <NUM> without an array of slots <NUM>. The region <NUM> is situated between, in a direct line from the source of vibrations, the attachment region <NUM> and the edge <NUM> and in particular in a radial line <NUM>, <NUM> with the contact point <NUM> or attachment region <NUM>. Therefore, vibrations from the venturi flow meter <NUM> are at least partly damped by the anti-vibration bracket <NUM> before reaching the differential pressure sensor <NUM>. In this way, vibrational forces transmitted to the differential pressure sensor <NUM>, welds and bolts are reduced and allows these features to have a greater service life and be more reliable than previously.

Vibration damping for the differential pressure sensor <NUM> by the anti-vibration bracket <NUM> is enhanced where at least some of the slots <NUM> of the array of slots <NUM> are located radially outwardly of the attachment region <NUM>. These slots <NUM> further isolate the attachment region <NUM> such that the region of the plate portion radially outward of the attachment region <NUM> is more flexible or has a reduced elastic modulus compared to a plate <NUM> region without an array of slots <NUM>. These slots <NUM> further dissipate the energy of the vibrations and enhance damping of the vibrations that might reach the differential pressure sensor(s) <NUM>.

Vibration damping by the anti-vibration bracket <NUM> is further enhanced where at least some of the slots <NUM>, <NUM> of the array of slots <NUM> are located to one or both lateral sides <NUM> of the attachment region <NUM>. Where there are two differential pressure sensors <NUM> or attachment regions <NUM>, some of the slots <NUM> are located there between. These slots <NUM>, <NUM> yet further isolate the attachment region <NUM> such that the region of the plate portion laterally of the attachment region <NUM> is yet more flexible or has yet further reduced elastic modulus compared to a plate <NUM> region without an array of slots <NUM>. These slots <NUM>, <NUM> further dissipate the energy of the vibrations and enhance damping of the vibrations that might reach the differential pressure sensors <NUM>.

At least some of the slots <NUM> of the array of slots <NUM> are arranged in at least two rows, e.g., rows <NUM>, <NUM> and <NUM>, with respect to the radial direction. The slots <NUM> in each row <NUM>, <NUM> and <NUM> are off-set from one another such that there is no clear 'line of sight' in the radial direction such that the radial line(s) <NUM>, <NUM> passes through at least one slot <NUM>. The region of the plate portion <NUM> having the array of slots <NUM> and in particular the spaced apart rows <NUM>, <NUM>, <NUM> has sufficient strength to support and attached together the components <NUM>, <NUM>, but also provides sufficient flexibility to dissipate and dampen the vibrations. Here, the length of each slot <NUM> in one row, e.g. row <NUM>, is greater than the gap between adjacent slots <NUM> in another row, e.g. row <NUM>, such that thee is no clear line of sight for vibrations to pass directly to the attachment region <NUM> as explained above. The length of each slot <NUM> in any row <NUM>, <NUM>, <NUM> may be the same length or may have different lengths. Different slot lengths may be required depending on the anti-vibration bracket's <NUM> geometry. Similarly, the gaps between adjacent slots <NUM> in any one or more of the rows <NUM>, <NUM>, <NUM> may vary to accommodate requirements such as geometry and/or structural integrity.

In general, and as can be seen in <FIG>, the slots <NUM>, <NUM>, <NUM>, <NUM> are arranged such that their or longest aspect is generally perpendicular to a radial line <NUM>, <NUM> that intercepts a mid-point or centre-point of the slot <NUM>, <NUM>, <NUM>, <NUM>. However, this is not always possible because of the geometry of the plate <NUM>, and it is preferable that some of the slots <NUM>, <NUM>, <NUM>, <NUM> of the array of slots <NUM> are arranged such that their longitudinal axis or longest aspect has an angle Θ that is between -<NUM>° and +<NUM>°, but preferably between -<NUM>° and +<NUM>° to a radial line <NUM>, <NUM> and at the centre-point of each slot <NUM>, <NUM>, <NUM>, <NUM>.

The slots <NUM>, <NUM>, <NUM>, <NUM> are shown as straight, however, at least some of the slots <NUM> may be curved and preferably the curved slots <NUM> have a curvature with a constant radius which is a radius from the axis <NUM>. All of the slots <NUM>, <NUM>, <NUM>, <NUM>, <NUM> of the array of slots <NUM> may be curved. The curved slots <NUM> can assist in providing more even spacing between each slot in the row of slots <NUM>, <NUM>, <NUM> and / or between rows of slots <NUM>, <NUM>, <NUM>.

The slots <NUM> are shown as elongate and with an aspect ratio > <NUM>, preferably > <NUM>, but in other embodiments the slots <NUM> may have an aspect ratio of <NUM>. Typically, the aspect ratio, length / width, of at least some of the slots <NUM> is between <NUM> and <NUM>. Where, each slot may have an aspect ratio between <NUM> and <NUM>. These slots <NUM> of the array of slots <NUM> are located between the first component <NUM> and the attachment region <NUM>.

The anti-vibration bracket <NUM> comprises an edge region <NUM> where there are no slots, i.e., the array of slots <NUM> is not within the edge region <NUM>. This forms a 'picture frame' and provides structural integrity to the anti-vibration bracket <NUM>.

Claim 1:
A subsea equipment assembly (<NUM>) comprising:
a first component (<NUM>) having an axis (<NUM>),
a second component (<NUM>), and
an anti-vibration bracket (<NUM>);
wherein the anti-vibration bracket (<NUM>) is attached to the first component (<NUM>) and the second component (<NUM>), and in use the first component (<NUM>) is caused to vibrate at least in a radial direction relative to the axis (<NUM>);
wherein the anti-vibration bracket (<NUM>) comprises a plate portion (<NUM>), and the plate portion (<NUM>) extends at least radially away from the first component (<NUM>) and comprises an attachment region (<NUM>) located a radial distance away from the first component (<NUM>), the second component (<NUM>) being attached to the attachment region (<NUM>);
wherein the anti-vibration bracket (<NUM>) comprises an array of slots (<NUM>), at least some of the slots (<NUM>) of the array of slots (<NUM>) are located between the first component (<NUM>) and the attachment region (<NUM>), and
wherein the plate portion (<NUM>) comprises an edge (<NUM>) having a complementary shape to an outer surface (<NUM>) of the first component (<NUM>), wherein the position of the edge (<NUM>) and the attachment region (<NUM>) is fixed with respect to one another;
characterized in that the edge (<NUM>) includes a plurality of notches (<NUM>), each notch provided to accommodate a foot (<NUM>) secured to the first component (<NUM>).