By-pass assembly has two positions; by-pass and close. It is in by-pass position during trip operation, and circulates mud fluid in the drill string into the annular space by-passing the idle motor, so that no mud may spray out onto the platform during the trip operation. When mud flow rate and pressure reach the setting value, the valve stem moves down and closes the valve. Meanwhile, mud stream flows through the motor, and converts the pressure energy into mechanical energy. As mud flow rate is too low, or mud pump stops, and as the pressure produced is not enough to overcome the spring force and the static friction force, the spring presses the stem upward, and by-pass is in open position. In general, the cross-over subs are used in deep well, large angle well, horizontal well or when hollow rotor is selected.
By-Pass Assembly And Parts,By-Pass Valve Assembly,Automatic Bypass Valve,Pressure Bypass Valve Weifang Shengde Petroleum Machinery Manufacturing Co., Ltd. , http://www.sdpetromachine.com
General surface support buoys are entensively used in single point mooring (SPMsystem. The three main type are as below:
Material: Swivel assembly: bows to BS970
                Gusets, flanges carbon steel to BS EN10025 Fe 430 A or B
                Central tube to BS 6323 Pt 3 HFS 5
Finish: Swivel assembly hot dip galvanized to BS 729 Zn2/Zn4 at 610 g/m2
Steelwok to be coal tar epoxy painted
Skin Colour: Orange, Yellow and others
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Subsea Buoyancy
Evergreen can make buoyancy material used for subsea up to 7000m. Product of different opplications buoyancys are manufactured upon our advance subsea buoyancy material. We can make subsurface mooring buoys , cable float, pipeline buoys, ROV buoyancy module , special buoys, and other synmatic foam products.
Our high-performance subsea buoyancy material and synmatic foam have the following performance.
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Item
Unit
Value
500m
1000m
1500m
4500m
Density
g/cm³
≤0.4
≤0.45
≤0.5
≤0.6
Compressive Strength
MPa
≥5
≥10
≥15
≥40
Hydrostatic Pressure
MPa
≥5
≥10
≥15
≥37
Water Absorption
%
≤2(5MPa,24h)
≤2(10MPa,24h)
≤2(15MPa,24h)
≤2(40MPa,24h)
Advantage of Evergreen pick- up buoys
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1,Advanced  framework design .
2.Over 20 year's expriences in marine buoys, more improvements are reflected  in production.
3.Durable practical.
4.More flexible,easy installation.
5.Safety and reliability.
6.Economical, Good after service.
7.Variety of end fitting to choose
8.Good technical supports
9.Abrasion resistant tough skin
 
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Subsea Buoy, Mooring Buoy, Surface Buoys
Trademark: Evergreen Maritime
Origin: Shandong, China