[PSUBS-MAILIST] Clearances

[Rick Patton via Personal_Submersibles]

Hey Sean,
The viewports are flat. Thanks for the data.

On Tue, Dec 10, 2024 at 6:12 AM Sean T. Stevenson via Personal_Submersibles
<personal_submersibles at psubs.org> wrote:

> Rick, is this a flat disc viewport, and not a dome?
>
> See an excerpt from ASME PVHO-1-2023 below. *Do*, where referenced, is
> the window major diameter.
>
> * 2-2.11.4 Flat Disk Windows*
>
> *2-2.11.4.1 Window External Diameter.*
>
> The dimensional tolerance of the external diameter of the window shall be
> based on the type of sealing arrangement for the window.
>
> * (a)* The external diameter of the flat disk window shall be within
> +0.000/−0.010 in. (+0.000/−0.25 mm) of the nominal value if the window is
> to be sealed in the seat cavity with a radially compressed O-ring.
>
> * (b)* The external diameter of the flat disk window shall be within
> +0.000/−0.060 in. (+0.000/−1.5 mm) of the nominal value if the window is to
> be sealed in the seat
> cavity with a seal ring wedged into the annular space between the
> retaining ring, the window’s bevel, and the cylindrical surface of the seat
> cavity.
>
> * (c)* The external diameter of the flat disk window shall be within
> +0.0/−0.125 (+0.0/−3.2 mm) of the nominal value if the window is to be
> sealed in the seat cavity with a flat elastomeric gasket axially compressed
> by the retaining ring.
>
> * (d)* The external diameter of the flat disk window shall be within
> +0.00/−0.02 *Do* of the nominal value if the window is to be sealed in
> the seat cavity with a room temperature curing elastomeric compound
> injected into the annular space between the edge of the window and the
> cylindrical surface of the seat.
>
> * (e)* The plane bearing surface of the flat disk window shall not
> deviate more than 0.001 *Do* from an ideal plane.
>
>
> *2-2.11.4.2 Seat Cavity Diameter.*
>
> The dimensional tolerance on the external diameter of the window seat
> cavity shall be based on the type of sealing arrangement for the window.
>
> *(a)* The diameter of the seat cavity for a flat disk window shall be
> within +0.01/−0.00 in. (+0.25/−0.00mm) of the nominal value if the window
> is to be sealed in the seat cavity with a radially compressed O-ring.
>
> *(b)* The diameter of the seat cavity for a flat disk window shall be
> within +0.06/−0.00 in. (+1.5/−0.00mm) of the nominal value if the window is
> to be sealed in the seat cavity with a seal ring wedged into the annular
> space between the retaining ring, the window’s bevel, and the cylindrical
> surface of the seat cavity.
>
> *(c)* The diameter of the seat cavity for a flat disk window shall be
> within +0.125/−0.000 in. (+3.2/−0.00mm) of the nominal value if the window
> is to be sealed in the seat cavity with a flat elastomeric gasket axially
> compressed by the retaining ring.
>
> *(d)* The diameter of the seat cavity for a flat disk window shall be
> within +0.01 *Do */−0.000 of the nominal value if the window is to be
> sealed in the seat cavity with a room-temperature curing elastomeric
> compound injected into the annular space between the edge of the window and
> the cylindrical surface of the seat.
>
> *(e)* The plane bearing surface of the seat cavity shall not deviate more
> than 0.002 *Do* from an ideal plane when measured with a feeler gauge
> inserted between the mating plane surfaces of the flat disk window or a
> circular plug gauge and the bare seat cavity. The axial force used to seat
> the window or the plug gauge shall not exceed 10 *Do* lb (4.53 *Do* kg)
> applied uniformly around its circumference.
>
> Sean
>
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