ADDITIVE INFLATABLE LEAK CONTROL BLADDER

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to leak checks in constrained spaces and, more particularly, to an approach for sealing a component assembly in a constrained space in order to perform a leak check.BACKGROUND

[0002] Component assemblies, including but not limited to brazed component assemblies, are commonly used in a variety of industrial applications including, but not limited to, gas turbine engine applications. To be useful, joints in component assemblies must be leak-free to permit select fluids, including liquids and gases, to flow through the component assemblies without leaking. To ensure leak-free joints, including but not limited to brazed joints, in component assemblies, component assemblies are typically leak checked after fabrication. A typical leak check includes sealing all openings in the component assembly and filling the component assembly with a pressurized fluid, e.g., water, air, nitrogen, or another fluid, and determining whether the sealed and pressurized component assembly will hold pressure. Alternately, the leak check can be conducted with a vacuum to determine whether the sealed and evacuated component assembly will hold a vacuum. Component assemblies are typically sealed with conventional sealing means including stoppers, bungs, and other sealing means know in the art. In some applications, though, component assemblies may be positioned in a physically and / or geometrically constrained space in a larger assembly that makes it difficult or impossible to seal openings in the component assemblies using conventional means.

[0003] US 2017 / 322102 A9 discloses a prior art conformal sealing fixture as set forth in the preamble of claim 1.SUMMARY

[0004] From one aspect of the present invention there is provided a conformal sealing fixture as recited in claim 1.

[0005] There is also provided a method of leak checking a component assembly positioned in an industrial assembly as recited in claim 7.

[0006] Features of embodiments are set forth in the dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1A is a view of an interior portion of a gas turbine engine assembly. Fig. 1B is another view of the interior portion of the gas turbine engine assembly of Fig. 1A. Fig. 2 is an isometric view an inflatable leak check bladder of this disclosure positioned in the interior portion of the gas turbine engine assembly of Figs. 1A and 1B. Figs. 3A to 3C are alternate views of the skin of the leak check bladder of Fig. 2 showing a smooth skin (Fig. 3A) in an arrangement outside the wording of the claims, a skin with an isogrid structure (Fig. 3B), and a skin with a partial isogrid structure (Fig. 3C). DETAILED DESCRIPTION

[0008] Component assemblies, including but not limited to brazed component assemblies, are typically leak checked after fabrication to ensure they can effectively perform their function as conduits for various fluids. Many different leak check procedures are known in the art. Typically, such procedures include sealing all openings in the component assembly and filling the component assembly with a pressurized fluid, e.g., water, air, nitrogen, or another fluid, and determining whether the sealed and pressurized component assembly will hold pressure. Alternately, the leak check can be conducted with a vacuum to determine whether the sealed and evacuated component assembly will hold a vacuum. Component assemblies are typically sealed with conventional sealing means including plugs, stoppers, bungs, and other sealing means know in the art. However, in some applications, component assemblies may be positioned in a physically and / or geometrically constrained space in a larger assembly that makes it difficult or impossible to seal openings in the component assemblies using conventional means to conduct the leak check.

[0009] Figs. 1A and 1B show an exemplary environment in which a component assembly 10 is positioned in a constrained space 12 that forms part of a larger industrial assembly 14. The industrial assembly 14 can be any of a number of industrial products that incorporate a component assembly 10. For example, the industrial assembly 14 can be part of a gas turbine engine as shown in Figs. 1A and 1B or some other industrial assembly. As depicted in Figs. 1A and 1B, the constrained space 12 can include one or more interior structures 16, 18 that can obstruct access to the component assembly 10, particularly to a port 20 in the component assembly 10. The interior structures 16, 18 depicted in Figs. 1A and 1B are examples of interior structures 16, 18 that can obstruct access to the component assembly 10 and are not meant to be limiting. A person of ordinary skill will understand that many other types and shapes of interior structures positioned in a constrained space of an industrial structure could obstruct access to a component assembly. As seen in Figs. 1A and 1B, the positioning of the interior structures 16, 18 in the constrained space 12 makes it difficult or impossible to seal the port 20 in the component assembly 10 so than the component assembly 10 can be leak checked.

[0010] Fig. 2 shows a conformal sealing fixture 22 configured to seal a port 20 in the component assembly 10. The conformal sealing fixture 22 includes an inflatable bladder 24 with a bladder body 26, a sealing surface 28, and an intake port 30. The bladder body 26 has an outer skin 32 surrounding a hollow inner volume (not shown directly). The bladder body 26 is formed from an elastomeric material such that the bladder body is configured to expand to a rigid or semi-rigid structure when in an inflated state and to collapse to a flaccid structure when in a deflated state. The sealing surface 28 is configured to form a leak-tight seal against the port 20 in the component assembly 10. The intake port 30 is configured to direct a pressurizing fluid into and out of the hollow inner volume of the bladder body to inflate the bladder to the inflated state and deflate the bladder body to the deflated state.

[0011] The bladder body 26 is configured to be positioned within the constrained space 12 in the industrial assembly 14 when the bladder body 26 is in the deflated state. As shown in Fig. 2, the bladder body 26 is configured to conform to the geometry of the constrained space 12 when the bladder body is in the inflated state. In this example, the bladder body 26 is structure to fit between interior structure 18 and the component assembly 10 and to surround partially interior structure 16. Optionally, the bladder body 26 can include a support face 34 that is configured to fit against an interior structure, such as interior structure 18, to stabilize and support the conformal sealing fixture 22 in the constrained space 12. Additionally, the bladder body 26 can be sized to provide a tight fit in the constrained space 12 when the bladder body 26 is in its inflated state also to stabilize and support the conformal sealing fixture 22 in the constrained space 12. As discussed further below, the outer skin 32 can be constructed with selected friction characteristics as an additional measure to stabilize and support the conformal sealing fixture 22 in the constrained space 12. When the bladder body 26 is in its inflated state, the sealing surface 28 engages with the port 20 in the component assembly 10 to form a leak-tight seal that will support a leak check test on the component assembly 10.

[0012] While the outer skin 32 of bladder body 26 is shown in Fig. 2 (see also Fig. 3A) with a smooth surface, which falls outside the wording of the claims, in accordance with the claims, the outer skin 32 is formed with an isogrid structure 36, shown in Figs. 3B and 3C, on all (Fig. 3B) or some (Fig. 3C) of the outer skin 32. As known, an isogrid structure 36 is a partially hollowed-out thin skin reinforced with a lattice structure having triangular integral stiffening ribs 38, sometimes called stringers. The isogrid structure 36 permits the bladder body 26 to contract and inflate like an accordion. When inflated, the isogrid's triangular pattern retains rigidity with less material than non-isogrid structures, thereby saving material and weight.

[0013] The conformal sealing fixture 22 is formed of an elastomeric material to allow it to inflate to an inflated state and deflate to a deflated state. The elastomeric material can be any material capable of inflating to form a leak-tight seal when the sealing surface 28 engages with the port 20 in the component assembly 10. For example, the elastomeric material can be natural rubber, artificial rubber, polyurethane, silicone rubber, or any other suitable elastomer. If the conformal sealing fixture is made with an additive manufacturing method as discussed below, the elastomeric material can be a light-curable resin useful in a stereo lithography process. The elastomeric material can be selected to impart desirable friction characteristics to the outer skin 32 to stabilize and support the conformal sealing fixture 22 in the constrained space 12.

[0014] The conformal sealing fixture 22 can be made with any method capable of forming a bladder body 26 having an outer skin 32 surrounding a hollow inner volume, which could be described as a shaped, balloon-like structure. For example, additive manufacturing techniques such as vat photopolymerization (e.g., stereolithography or other techniques known as vat photopolymerization) or material jetting can be used to create the bladder body 26 with the desired geometry and mechanical properties. In one option, the outer skin 32 can be formed from an elastomeric material as discussed above with a soluble resin used to form an interior space between the outer skin 32. The soluble resin can be any material can be dissolved or washed out of the bladder body 26 after it is formed to create the hollow inner volume surrounded by the outer skin 32. As discussed some or all of the outer skin 32 is formed with an isogrid structure 36 as deemed appropriate for a particular application. of the bladder.

[0015] The conformal sealing fixture 22 described above will reduce time to provide a seal to leak check a component assembly 10 that is positioned in constrained space 12 and eliminate multi-part complex fixtures and seals. The conformal sealing fixture 22 also has built in mistake-proofing due to the bladder body 26 being conformal to geometry of the constrained space 12 in which it is intended to be used.

[0016] While the invention has been described with reference to an exemplary embodiment(s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A conformal sealing fixture comprising: an inflatable bladder (24) having: a bladder body (26) having an outer skin (32) surrounding a hollow inner volume, wherein the bladder body (26) is formed from an elastomeric material such that the bladder body (26) is configured to expand to a rigid or semi-rigid structure when in an inflated state and to collapse to a flaccid structure when in a deflated state; a sealing surface (28), wherein the sealing surface (28) is configured to form a leak-tight seal against a port (20) in a component assembly (10); and an intake port (30) configured to direct a pressurizing fluid into and out of the hollow inner volume of the bladder body (26) to inflate the bladder to the inflated state and deflate the bladder body (26) to the deflated state; wherein the bladder body (26) is configured to be positioned within a constrained space (12) in an industrial assembly (14) when the bladder body (26) is in the deflated state and is configured to conform to a geometry of the constrained space (12) when the bladder body (26) is in the inflated state, such that when the bladder body (26) is in the inflated state, the sealing surface (28) engages with the port (20) in the component assembly (10) to form a leak-tight seal, characterised in that at least a portion of the outer skin (32) comprises an isogrid structure (36).

2. The conformal sealing fixture of claim 1, wherein the elastomeric material is selected from the group consisting of natural rubber, artificial rubber, polyurethane, and silicone rubber.

3. The conformal sealing fixture of claim 1, wherein the elastomeric material is a light-curable resin useful in a stereo lithography process.

4. The conformal sealing fixture of any preceding claim, wherein the component assembly (10) is configured to operate as a fluid conduit in the industrial assembly (14).

5. The conformal sealing fixture of any preceding claim, wherein the constrained space (12) includes one or more interior structures (16, 18) that impede access to the port (20) in the component assembly (10).

6. The conformal sealing fixture of any preceding claim, wherein the industrial assembly (14) is a structure of a gas turbine engine.

7. A method of leak checking a component assembly (10) positioned in an industrial assembly (14), comprising the steps of: inserting an inflatable bladder (24) into a constrained space (12) of the industrial assembly (14), wherein the inflatable bladder (24) is in a deflated state; inflating the inflatable bladder (24) to a rigid or semi-rigid inflated state by directing a pressurizing fluid through an intake port (30) in the inflatable bladder (24) into a hollow inner volume of a bladder body (26), thereby causing the inflatable bladder (24) to conform to a geometry of the constrained space (12) and causing a sealing surface (28) of the inflatable bladder (24) to engage with a port (20) in the component assembly (10) to form a leak-tight seal; conducing a leak check test on the component assembly (10); deflating the inflatable bladder (24) by evacuating the pressurizing fluid from the intake port (30) in the inflatable bladder (24), thereby causing the inflatable bladder (24) to enter a flaccid deflated state; and removing the inflatable bladder (24) from the constrained space (12) of the industrial assembly (14), wherein the bladder body (26) includes an outer skin (32) that defines the hollow inner volume of the bladder body (26) characterised in that at least a portion of the outer skin (32) comprises an isogrid structure (36).

8. The method of claim 7, wherein the bladder body (26) is formed from an elastomeric material such that the bladder body (26) is configured to expand to a semi-rigid structure when in an inflated state and to collapse to a flaccid structure when in a deflated state.

9. The method of claim 8, wherein the elastomeric material is selected from the group consisting of natural rubber, artificial rubber, polyurethane, and silicone rubber.

10. The method of claim 8, wherein the elastomeric material is a light-curable resin useful in a stereo lithography process.

11. The method of any of claims 7 to 10, wherein the component assembly (10) is configured to operate as a fluid conduit in the industrial assembly (14).

12. The method of any of claims 7 to 11, wherein the constrained space (12) includes one or more interior structures (16, 18) that impede access to the port (20) in the component assembly (10).

13. The method of any of claims 7 to 12, wherein the industrial assembly (14) is a structure of a gas turbine engine.