PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin

Nathan Wolverton October 9, 2017

EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 1 of 7

Preferred Seal Orientation

for Pressure Control Equipment
1. Scope
This bulletin has been created to clarify Cameron’s policy on the preferred seal orientation
for Ram BOPs, Annular BOPs, and Collet Connecters.

2. Seal Types
There are four primary seal types that are used in Cameron BOPs and Connectors: O-rings,
D-Seals, T-Seals, and lip seals. O-rings, D-seals, and T-seals are symmetrical in the
sealing direction and therefore have no preferred orientation. However, lip seals have
unsymmetrical geometry. The lip end (i.e. O-ring end) utilizes both pressure and O-ring
compression to energize the seal while the heel end utilizes O-ring compression only.

3. Unidirectional Seals
Most seals used in BOPs and Connectors are required to seal from one direction only.
D-Seals and T-Seals have no preferred orientation in unidirectional applications. Lip seals
should be oriented with the lip end (the side with an O-ring) facing the applied pressure (see
Figure 1).

Figure 1 – Standard Seal Orientation for Unidirectional Application

4. Bidirectional Seals
Due to their symmetrical geometry, T-Seals and D-Seals have no preferred orientation in bi-
directional application. The bidirectional sealing capability of a lip seal must be evaluated on
a case-by-case basis with the seal manufacturer. In most BOP applications, a lip seal will
function as a bidirectional seal. In some cases, the addition of a PIP ring is required to
improve bidirectional performance. To maintain a standard orientation, lip seals (with or
without a PIP ring) should be installed following the below equipment-specific
recommendations.

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 2 of 7

U BOP
The U BOP operating piston seal is a lip seal used in a bidirectional application. To
mitigate potential seal damage during assembly, the preferred orientation of this seal is
with the lip end facing the ‘Open’ chamber and the ram (see Figure 2).

Figure 2 – U BOP Seal Orientation

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 3 of 7

TL BOP
The TL BOP operating piston seal is a lip seal used in a bidirectional application. The
preferred piston seal orientation is with the lip end facing the ‘Close’ chamber and the
tail rod (see Figure 3). In this orientation, the pressure energizing feature of the lip
seal faces the more critical “Close” function which also has the higher pressure rating.

The lip seal on the Cylinder Head should be oriented away from the ‘Close’ chamber,
towards the lock. This orientation is recommended to mitigate potential seal damage
during assembly.

A change of seal orientation is not considered critical for BOPs in service. The BOP is
fit for purpose with the operating piston seal oriented to the ‘Open’ chamber. However,
for consistency, Cameron recommends that the seal orientation be changed to the
preferred orientation at the next scheduled maintenance.

Figure 3 – TL BOP Seal Orientation

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 4 of 7

EVO BOP
The EVO BOP does not have any seals used in a bidirectional application. All lip seals
should be oriented with the lip facing the applied pressure (see Figure 4).

Figure 4 – EVO BOP Seal Orientation

Collet Connector
The seals on the secondary unlock piston can see pressure from either the ‘Primary
Open’ chamber or the ‘Secondary Open’ chamber and therefore must seal
bidirectionally. For consistency and standardization Cameron recommends that both
the OD and ID lip seals on the secondary unlock piston be positioned with the lip end
facing the ‘Secondary Open’ chamber per Figure 5. In this orientation, the pressure
energizing feature of the lip seal favors the contingency unlock function.

All other connector seals are in unidirectional applications and should be oriented with
the lip end toward the applied pressure.

Figure 5 – Collet Connector: Secondary Unlock Piston with Solitary Lip Seals

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 5 of 7

Pip and backup rings have been added to some connector models to improve both
bidirectional sealing performance and anti-extrusion resistance. The preferred
orientation for this seal configuration is with the lip end facing the ‘Primary Open’
chamber per Figure 6. The introduction of the PIP and Back-up rings require a larger
gland resulting in the lip seal being positioned closer to the secondary unlock porting in
the cylinder. The preferred orientation ensures the lips of the lip seal are generously
spaced from the porting during operation.

The Connector will function correctly with any secondary unlock seal orientation.
However, for consistency, Cameron recommends that the seals be changed to the
preferred orientation at the next scheduled maintenance.

All other connector seals are in unidirectional applications and should be oriented with
the lip end toward the applied pressure.

Figure 6 – Collet Connector: Secondary Unlock Piston with Pip and Backup Rings

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 6 of 7

Annular BOP
The piston seals of the DL Annular BOP are the only seals used in a bidirectional
application. These piston seals can be either lip seals, D-seals, or T-seals. The D-
seals and T-seals are symmetrical seals that have no preferred orientation. If the
Annular BOP piston is equipped with lip seals, they should be oriented with the lip end
facing the “Close” Chamber (see Figure 7). In this orientation, the pressure energizing
feature of the lip seal faces the more critical “Close” function.

All other DL seals are used in unidirectional applications. The D-seals and T-seals are
symmetrical seals that have no preferred orientation. Lip seals should be oriented with
the lip end facing the applied pressure (see Figure 7).

The T-90 Annular BOP has no bidirectional seals. As with the other equipment, lip
seals should be oriented with the lip end facing the applied pressure. The T-90 BOP
also utilizes a U-Seal in addition to the lip seal. The open end of the U-seal should face
toward the applied pressure.

Figure 7 – DL Annular BOP with Lip Seals

CAM-356nc
PROPERTY OF DRAWN BY DATE REVISION Engineering Bulletin
Nathan Wolverton October 9, 2017
EB 539 D
APPROVED DATE
D1
Greg Landthrip October 9, 2017 Page 7 of 7

5. Conclusion
Cameron has standardized on the preferred seal orientations described in this Engineering
Bulletin. This Bulletin supersedes all assembly drawings, procedures, and manuals. These
documents will be updated, if needed, to be consistent. No immediate action is required for
components currently in service. However, for consistency, Cameron recommends that the
seal orientation be changed to the preferred orientation at the next scheduled maintenance.

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