特有的优点：
EXCLUSIVE FEATURES:
- 抗高温波动，这种波动往往会损坏铸造阀门。
Resists high temperature fluctuations which damage
cast steel valves.
- 所有阀座和滑动件表面都是硬面钨铬钴合金6。
All seating & sliding surfaces hardfaced with
Stellite 6.
- 不旋转阀杆
Non-rotating stem
- 密封焊接的螺栓阀帽。
Bolted bonnet with seal weld.
- 柔性楔板，可以在短暂高温(482-204oC)下工作。
Flexible wedge which remains operable in 900-400oF
(482-204oC) transients.
计算频繁温度波动期间表面应力的公式
请参阅第9页。
Formula for Calculating Surface Stress
during frequent temperature fluctuations
see page 9. |
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催化重整装置对阀门的挑战
THE CATALYTIC REFORMING VALVE CHALLENGE
频繁的温度波动使阀门承受着过度的压力，这种压力容易造成铸钢阀门阀体孔内部表面裂缝。如果内部氢气泄露到大气中可能会导致爆炸。因此阀门必须具有紧密的密闭性。平行滑动或双阀瓣阀门在这种应用场合中经过短暂使用后，容易出现泄漏。柔性楔板的设计必须恰当，使之在冷却器挤压铆钉楔板时，能够承受住环境冷却过程中管道的过度压力。
Frequent temperature fluctuations expose the valve
to excessive stresses which cause surface cracks in the body bores of
cast steel valves. Leakage to the atmosphere in the presence of hydrogen
could lead to an explosion. The valves must have tight closure. Parallel
slide or double disc valves tend to leak after a short period in this
service. The flexible wedges must be properly designed to resist the excessive
piping forces during the cool down operation when the cooler body squeezes
against the hitter wedge.
催化重整运行模式
CATALYTIC REFORMING OPERATING MODES
- 正常运行。DN250的再生阀关闭。工业生产液流压力为275-300 psig (19-20.6 bar), 温度为(487-510oC)，流体通过DN400闸阀和反应堆一至二周。
Normal Operation. The 10" regeneration
valve is closed. The process stream at 275-300 psig (19-20.6 bar),
910-950oF (487-510oC),flows through the
16" gate valve and the reactor for one to two weeks.
- 再生。DN400阀门关，反应堆减压至190 psig (13 bar), 温度 (385-482oC)。再生循环持续21至24小时。在此阶段，关闭阀门阀体冷却了大约204oC。
Regeneration. The 16" valve is closed
and the reactor is depressurized process at 190 psig (13 bar),
725-900oF (385-482oC). The regeneration
cycle lasts 21 to 24 hours. During this period, the closed valve
body cools down by nearly 400oF (204oC).
- 再流动。DN250阀门关闭，DN400阀门开启，开始正常运行。
Re-streaming. The 10" valve is closed
and the 16" valve opens for normal operation.
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Velan的解决方案
THE VELAN SOLUTION
Velan可提供具有特殊结构设计的楔板的锻造闸阀。这种阀门具有钨铬钴合金阀座和导轨表面，以及能够抵抗温度波动影响的柔性楔板。Velan阀门所采用的锻造阀体在抗蠕变能力方面比铸造阀体强三倍以上。（请参阅第9页的“计算表面应力的公式”）
Velan supplies forged gate valves with specially
designed wedges. The valves have Stellite seating and guiding surfaces
and flexible wedges designed to resist the effects of temperature fluctuations.
Forged bodies used in Velan valves show more than three times better resistance
to creep than cast bodies (see Formula for Calculating Surface Stress,
page 9).
压力界限通过密封-楔板，阀体-阀帽连接和动负载填料腔来保证。动负载填料腔，采用Belleville垫圈来保持最小永久性填料压力，这种垫圈是由Velan在1970年开发的。
The pressure boundary is secured by a seal-welded
body-bonnet joint and a live-loaded packing chamber. Live-loaded packing
chambers, which use Belleville washers to maintain minimum permanent packing
stress, were developed by Velan in 1970.
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