The high pressure gate valve, also called pressure seal gate valve, is designed and manufactured according to ASME B16.34, API600, and the valve has the characteristics of beautiful appearance, compact structure and reliable seal. It is suitable for various pipelines of Class900 to Class4500.
Operating principle pressure gate valve:
Before the high pressure gate valve is boosted, turn the tightening bolt to raise the bonnet, so that the initial formation between the bonnet, the segment ring, and valve body created sealing condition – preload pressure on the sealing surface. When the media pressure increases, the sealing pressure between the bonnet, segment, valve body increases gradually with the increase of medium pressure. In self-tight sealing, the working seal pressure on the sealing surface is synthesised by two parts: one is the pre-tight seal pressure, and the other is the pressure formed by the pressure of the medium. It should be emphasised that: the media pressure in a self-tightening seal always tends to increase the preload seal pressure to increase sealing performance. The higher the media pressure, the greater the operating seal pressure and the better the sealing performance.
The main features of the high pressure gate valve:
① The self-sealing structure can make the connection between the valve body and bonnet of the high-pressure valve tightly structured, labor and material saving, safe and reliable.
② The high pressure gate valve uses a combined structure at the bonnet pressure self-sealing, to achieve a linear seal, while its seal ring uses Austenitic stainless steel, anti-corrosion, extends the life of the use, thus ensuring that the valve seal is not leaking under high pressure difference.
③ When the high pressure gate valve is in the 2500LB and above, the inner cavity of the valve body and the contact area of the sealing ring are welded with stainless steel material to avoid the valve body sealing area being eroded by air and water under high pressure difference, which may cause pitting leakage, thus ensuring the safe and long-term operation of the valve.
Self-sealing structure of the high pressure gate valve:
The pressure seal gate valve uses a sealing structure combined with the packing outer seal and the internal pressure self-sealing at the stem seal to ensure that the medium does not leak. The outer seal of the stem is filled with polytetrafluorene or O-ring packing, which is pressed tightly with packing gland. Under the action of media pressure, the upward pressure is generated, the greater the pressure of the medium, the greater the sealing force, this structure is suitable for high media.