7 1/16-3000PSI HRSB double Ram BOP manual service
3. Operating Principles
3.1. Principles of the Open and Closure of the Ram
Figure 4 Hydraulic Oil Circuit Diagram for Ram Open and Closure
When the high pressure oil of the hydraulic control system is introduced into the
left and right hydraulic cylinder ram closure chambers, the impelling piston drives
the ram shaft and the left and right ram assembly to the center of the wellhead
along the Ram Block chamber to close the well. When the high pressure oil is
introduced into the left and right hydraulic cylinder ram open chambers, the
impelling piston drives the ram shaft and the left and right ram assembly away from
the center of the wellhead to open the well. The open and closure of the ram is
controlled through the reversal valve of the hydraulic control unit. Generally the
open and closure operations can be completed within 3 to 15 second (but
correlated with the status of the hydraulic control system, the specifications of the
hydraulic control line and the length of this line).
3.2. Principles of Well Pressure Sealing
A ram blowout preventer can only effectively close a well when all the four seals
have taken effect. These four seals include the seal between the ram top seal and
the body, the seal between the ram front seal and the pipe, the seal between the
body and the bonnet, and the seal between the ram shaft and the bonnet.
The ram sealing process is divided into two steps. In the first step the hydraulic oil
forces the ram shaft to impel the Front Packer rubber element to make it deformed
7(2)FZ18-35 Ram Blowout Preventer Rongsheng Machinery Manufacture Ltd. of Huabei Oilfield, Hebei
and seal the front part and it also lets the Top Seal rubber element be interfered
and compressed to fill the gap between the Top Seal element and the body and
seal the top, thus finish the primary sealing. In the second step, with the help of the
pressure inside the well the ram is impelled from behind to allow the further
deformation of the Front Packer element and the ram is also impelled from the
bottom to let the body adhere tightly to the Top Seal element and thus achieve the
reliable sealing of the well. This is called the well pressure assisted sealing effect.
8(2)FZ18-35 Ram Blowout Preventer Rongsheng Machinery Manufacture Ltd. of Huabei Oilfield, Hebei
4. Structures and Features of the Main Components
4.1. The Features of Ram Blowout Preventer
Such major pressure bearing components as the body and the bonnet are cast
formed with alloy steels of high strength and high malleability and properly heat
treated. And the water pressure test for strength is performed for each preventer
according to the API Spec 16A standards before ex factory.
At the bottom of the chamber of the body and the ram there are high brace rods
and a sand depositing slot towards the well bore. So the sands and silts can be
removed automatically when the ram is opened and closed. This can reduce the
kinetic frictional resistance of the ram and is also helpful to the well pressure
assisted sealing of the ram. The inner surface of the ram chamber is smooth and
easy to clean.
A kind of floating ram sealing is adopted to reduce the resistance in opening or
closing the ram, minimize the wearing of the rubber elements and lengthen the
service life of the ram. It also prevents the body and ram from rusting together and
thus is easy to disassemble.
The retainers for the packing of the ram shaft are stainless steel and the slot for the
retainers is welded with stainless steel to improve the corrosion proof capability of
the blowout preventer.
The surface of the top seal of the chamber between the body and the ram of the
blowout preventer is chemically nickel plated to effectively improve its corrosion
resistance and its wear resistance.
The HF integral structure is adopted for the ram block. This allows the easy
assembling and disassembling of the sealing elements and the easy replacing and
repairing of the ram.
The NPT 1” female threads are adopted for the hydraulic connection threads and
are placed at the top. After the NPT 1” female threads on the hinge mount are
damaged the hinge mount can be replaced.
The dimensions of the external connections are in conformity with the API Spec 6A
norms.
4.2. Pipe Ram
9(2)FZ18-35 Ram Blowout Preventer Rongsheng Machinery Manufacture Ltd. of Huabei Oilfield, Hebei
10
Figure 4 HF Pipe Ram
Table 6 Part List of the HF Ram Assembly
No.
3
2
1
Name
Ram
Assembly
Ram Block
Front Packer
Top Seal
Quantity
Ram
Specification
1
1
1
C.S.O.
RS11138.03.01.00
RS11138.03.01.01
RS11138.03.01.02
RS11138.03.01.03
2 3/8"
RS11138.03.02.00
RS11138.03.02.01
RS11138.03.02.02
RS11138.03.01.03
2 7/8"
RS11138.03.03.00
RS11138.03.03.01
RS11138.03.03.02
RS11138.03.01.03
3 1/2"
RS11138.03.04.00
RS11138.03.04.01
RS11138.03.04.02
RS11138.03.01.03
4"
RS11138.03.09.00
RS11138.03.09.01
RS11138.03.09.02
RS11138.03.01.03
4 1/2"
RS11138.03.05.00
RS11138.03.05.01
RS11138.03.05.02
RS11138.03.01.03
Φ12 cable
RS11138.03.06.00
RS11138.03.06.01
RS11138.03.06.02
RS11138.03.01.03
2 7/8"-3 1/2"
RS11138.03.07.00
RS11138.03.07.01
RS11138.03.07.02
RS11138.03.01.03
Φ8 cable
RS11138.03.08.00
RS11138.03.08.01
RS11138.03.08.02
RS11138.03.01.03
Φ11 cable
RS11138.03.11.00
RS11138.03.06.01
RS11138.03.11.02
RS11138.03.01.03
1.9"
RS11138.03.10.00
RS11138.03.10.01
RS11138.03.10.02
RS11138.03.01.03
4.3. Ram Shaft Sealing Device
A kind of assembled two way seal is adopted for the sealing between the bonnet
and the ram shaft, a kind of V shaped assembled seal ring is used to seal the well
pressure, a kind of Y shaped seal ring is used to seal the oil pressure and a kind of
O shaped seal ring is used as the auxiliary sealing. Please see figure 5.
1
2
3 (2)FZ18-35 Ram Blowout Preventer Rongsheng Machinery Manufacture Ltd. of Huabei Oilfield, Hebei
11
Table 7 Part List of the Ram Shaft Sealing Device
No.
Part No.
Name
Quantity
1
Retainer 105
Retainer for holes
1
2
SFZ1.22
Pressure disk
1
3
SFZ1.21
V Ring
3
4
F9404.23
Support Ring
1
5
GB1235-76
O ring 90x5.7
1
6
RJ12326.25A
Y Ring
1
Note: The quantity in this table is the quantity needed for one bonnet.
Figure 5 Structure of the Ram Shaft Sealing
4.4. Locking Shaft Sealing Device
Please see Figure 6 for the locking shaft sealing device. (2)FZ18-35 Ram Blowout Preventer Rongsheng Machinery Manufacture Ltd. of Huabei Oilfield, Hebei
12
Figure 6 Locking Shaft Sealing Device
Table 8 Part List of the Locking Shaft Sealing Device
No.
Part No.
Name
Quantity
1
Retainer 85
Retainer for holes 1
2
GB1235-76
O ring 56x3.5
2
3
GB3452.1
O ring 73x3.55
2
4
F9405.12
Sealing sleeve
1
5
F751.14.17
Dust-proof Ring
1
Note: The quantity in this table is the quantity needed for one
locking shaft.
