Steam extraction check valve

• Features and performance
• 1.CKH valve is suitable for uses in an urgent stop of flowing back or in the conduits of power plant turbine system.It can be shut off within 0.5~1 second to prevent turbine from damage due to the steam and condensate flowing back in the conduits.
• 2.The disc is positioned at a large inclined angle to shorten the travel of opening or closing and also has one auxiliary pneumatic (hydraulic)device for quick closing.
• 3.With the main eccentric structure plus the auxiliary pneumatic (hydraulic)pressure on the disc,the flow stopping and checking functions are realized.
• 4.The triple eccentric structure facilitates an immediate opening or closing with least friction.
•  
• Structure & features
• Combination of non-return and shutting -off functions fast closing fast closing within 0.5 second without water hammer
• CKH valve is used in the conduits of power plant turbine system to quickly shut off the flow in urgent circumstances so as to prevent the turbine from damage due to the flow back of steam and condensate in the conduits.The valve system comprises a valve,an auxiliary pneumatic shutting-off device,a pneumatic control system(equipped by customers themselves),etc.(The auxiliary shutting-off device can use hydraulic control according to customers’requirements.)When the turbine begins to work,the air in the air supply device of the control system enters the bottom chamber of the auxiliary shutting -off cylinder,pushes the piston to move up and compress the spring to accumulate energy,and the disc begins to open under the pressure of mediums in the conduits.When a breakdown occurs,the pressure of mediums in the conduits .When a breakdown occurs,the pressure of mediums in the conduits decreases and the disc will close by the its own gravity ,and at the same time the air supply control device changes the air flow direction to lead the air into the upper chamber of the cylinder,which,combined with the spring,pushes the piston to move downward,expelling the air in the lower chamber to assist the disc to close at a maximum speed (See Figure 1 for details).Therefore,the turbine and other main equipments are effectively prevented from damage as a result of the back flow of the steam and condensate in the conduits.
•  
• Problems & Shortcomings Of Traditonal Check Valves
• Swing check valve:
• Due to the structural limitations in the general swing check valves,the opening speed is low and the rotary inertia of disc is quite big.thus effecting a strong impact on the valve seat,which easilly causes damages on the rotary shaft,swing spindle and seal faces,resulting a leakage and failures (See illustration 2for details).
• 
• General butterfly check valve:
• It adopts soft rubber seal,duo-eccentric arrangement and vertical disc,so the valve cannot depend on its own gravity to complete closing with long closing stroke and big impact,and the rubber is of easy aging to cause leakage(See illustration 3 for details).
•  
• CKH Fast-Closing Steam Extracting Check Valve
• Direction
• Standards
• Designing & manufacturing are according to the regulations of ANSI 16.34 and BS 51.55.
• Flange is subject to ANSI 16.5,MSS-SP-44,ISO7005.
• Face-to-face dimension is by the regulation of Enterprise standards.
• Pressure test is according to API598,ISO 5208.
•  
• Coding system
• 
•  
• Main Properties & Materials of components & parts:

  NO.	Name	Carbon steel	Alloy steel	Stainless steel
  1	Valve body	A216 WCB	A216 WC6	A351 CF8	A351 CF8M
  2	Retaining ring	A216 WCB	A216 WC6	A351 CF8	A351 CF8M
  3	Assistant closing shaft	A297 420	A297 420	A182 F304	A182 F314
  4	Yoke	A216 WCB
  5	Piston rod	A194 2H, A276 420
  6	Piston	Ductile catiron
  7	Packing	Flexible graphite
  8	Seal ring	410,430		304	316
  Suitable mediums		Water,steam
  Suitable temperature		-29~425℃	-29~595℃	-196~600℃

•  
•  
• Dimensions
• 
• PN1.0MPa

  DN	mm	300	400	500	600	700	800	900	1000	1200
  	in	12	14	20	24	28	32	36	40	48
  L(RF-BW)		400	500	600	700	800	900	1000	1200	1300
  H		946	998	1052	1131	1258	1449	1591	1793	2009
  W.T.(Kg)		523	651	894	1268	1741	2243	2564	3178	3904

•  
• PN1.0MPa

  DN	mm	300	400	500	600	700	800	900	1000	1200
  	in	12	14	20	24	28	32	36	40	48
  L(RF-BW)		400	500	600	700	800	900	1000	1200	1300
  H		953	1007	1061	1138	1263	1457	1598	1802	2017
  W.T.(Kg)		533	674	962	1362	1842	2365	2712	3408	4179

•  
• PN1.0MPa

  DN	mm	300	400	500	600	700	800
  	in	12	14	20	24	28	32
  L(RF-BW)		400	500	600	700	800	900
  H		976	1023	1075	1163	1281	1473
  W.T.(Kg)		556	709	1015	1452	1966	2527

•  
• PN1.0MPa

  DN	mm	300	400	500	600
  	in	12	14	20	24
  L(RF-BW)		400	500	600	700
  H		976	1023	1075	1163
  W.T.(Kg)		612	778	1103	2136

PDF DOWN