BL6 Premium Connection

BL6 is used for high pressure well, BL6/BL8, deep well, and ultra-deep well. It can improve resistance of inner high pressure and connection strength and resolve the problem of galling

• BL6 is with coupling, and ID of pipe end and pipe body is the same

• BL6 connection is 6RD, and it have better connection property (Stress relaxation)

• Though small angle connection on bearing surface, low thread tooth height and small taper thread, it has better usage property

• BL6 is series production, and used widely. With special thread structure, BL6/BL8 is designed for special service condition. The connection strength can reach 100% inner yield strength of pipe body.

  
  

BL6 structure

• The connection strength can reach strength of pipe body. Gas seal ability is the same to inner yield pressure. Permit to many time of make-up and make-down. No Inner thread and outer thread taper fit. Longer upsetting length.

BL6/BL8 thread design

• Though two-level hook thread and 7.5° thread bearing surface, it is easy to gall and better connection strength

• With 20°thread profile, it is easy to make-up and rorating.

• Though adjusting pitch diameter, and decreasing interference of inner and outer thread, it make the make-up torque work on torque shoulder, and so increase connection efficiency and anti-rust ability.

• For BL6 connection, it is 6RD, and it have better connection property (Stress relaxation); for BL8 is 8RD, it have quicker beak-up speed.

• Though two level straight taper thread design, it improve twice make-up speed.

BL6 shoulder design

They are designed to multilevel right angle, negative angle mixed shoulder form

• Though adjusting pitch diameter, and decreasing interference of inner and outer thread, it make the make-up torque work on torque shoulder, and so increase connection efficiency and anti-rust ability.

• Though right angle design of main shoulder, it make spherical to cone interference of main seal surface

• Though negative torque shoulder design and -30°negative self-locking angle,it improve anti bending ability

• Though right angle shoulder design, it is near to secondary seal surface, it could improve assistance seal on interference of make-up torque

• Though big root rounded design, it decrease stress of should root. And it resolve the danger of stress concentration on section by reasonable stress distribution under function of make-up torque

• Though three shoulders design, it make torsional strength much more bigger than other premium connection. So, this connection not only bear super high inner pressure and so used for fracturing, acidizing, salvaging and accident ofpipe string.

BL6 seal design

Metal to metal seal (two steps) and shoulder (three-level assistance) sealBy metal cone to metal cone of main seal surface, his advantage is as follows:

• Cone/cone linear sealing, it has bigger contact pressure on seal surface, and d due to shorter length of seal surface, it is easy to process.

• With big seal surface, it has better seal property. Include assistant seal function of shoulder, it can keep seal property in complicated load condition such as tension ,bend and high inner pressure

• Due to Interference design of main seal surface with cone metal to cone come ,one secondary seal surface in three shoulder and three assistance seal surface , the connection strength can reach 100% inner yield strength of pipe body.