Design Construction for sleeved type

 

Design Features for sleeved type

Design more economical, flexible, and compact fluid handling systems. 
Bi-directional flow, simple actuation, lightweight, compact design, and multiport configurations all facilitate improved system design.
Superior, longer-lasting in-line sealing.
The inert PTFE sleeve completely surrounds the plug. The sleeve provides a large, circumferential sealing surface from port to port. Open, closed, or rotating, the seal is assured. No ball or gate valve can match this sealing power.
Secure sealing with no cold-flow, deformation, or rotation of the sleeve. 
The sleeve is securely nestled in the valve body. High pressure ribs, top and bottom retention, and 360° port lips all assure sleeve containment.
No seizing. No sticking. 
As the plug rotates, the 360° port lips provide a self-cleaning action to remove scaling and adhering media.
No cavities. No contamination. 
There are no body cavities where flow media can accumulate and contaminate future processing. This cavity-free design also prevents sticking.

 

Design For Stem Sealing of sleeved plug valves
There’s a fully adjustable in-line seal and dual stem seal.
 

Fire Safe And Anti-Static Functions of sleeved plug valves

API-607 Standards.
For External Leakage. These valves exceed the sealing requirements specified in those standards. A tight external seal was maintained even after the PTFE sleeve and sealing parts were totally destroyed by fire.
Fire tested stem seal.
A metal diaphragm overlays the PTFE diaphragm and a Graphite packing surrounds the stem. If the PTFE diaphragm and wedge ring are destroyed by fire, the metal diaphragm and graphite packing maintains the seal.
Fire tested cover seal.
In the standard valve, if the PTFE sleeve and diaphragm are destroyed by fire, leakage would occur at the cover joint. The flexible graphite cover seal prevents this. It is fitted into a machined counter bore in the valve body. The cover bolts compress the graphite ring between the valve body and cover. Even if fire occurs, this seal is maintained.
Vented plug.
In fire tested valves, the plug is vented on the upstream side. This relieves the expansive pressure caused by the heat of the fire. Valves with vented plugs are unidirectional. An arrow stamped on the valve body indicates the flow direction.
 

Standard Design for lubricated plug valves


 

Design Features for lu1bricated plug valves

1) Not only does Spherical shape body reinforced with ribs ,which is design with FEA, give valves a heavy-wall body, constructed beyond its requirements as a pressure vessel for its maximum rated working pressure to withstand the higher-than-line sealant pressure and expected line stresses, but also reduced the whole valve weight. 
2) Three passes stem sealing consisting oftwo O-rings and an emergency sealant sealing which was threaded into the slot on the stem with a sealant injection fitting. 
3) A big chamber in the body to stock grease in order to lengthen using time for a grease-adding in its applications and the pressure of the plug sealant, acting on the upper face of the plug, is utilized to react against the upward force to reduce the possibility of taper locking. 
4) A complete and scientific grease sealing system consisting of a check valve, an injection fitting, two connecting slots and two blind slots in the plug and two grease reservation slots in the body makes sure the trim surfaces cover the grease all the time, no leakage takes place during being used. 
5) A flexible adjusting-plug devise consisting of a dog/dog center, steel washer, an adjustable stud and a corn nut protecting the stud from being rusty guarantees the valves sealed easier and more humanistic. 

 

Excellent Performance Functions

	Locking Device & Blow-out proof stem a ) There are two locking holes in the stopper 1); b ) There is a locking hole in the upper cover 2); c ) The locking holes in 1) match the one in 2) when the valve locates the open or close position so the locking function is carried out. d ) There is a shaft shoulder in the stem 3) which makes stem be installed from the bottom of the body, therefore stem can’t be taken out from the upper cover direction for shoulders block so blow-out proof stem function is implemented.
	1) Flexible Graphite Packing for Stem Firesafe 2) Stick grease slot with a injection fitting for stem emergency. 3) A combination of a graphite gasket, a SS and a CS diaphragm carries out the cover firesafe.
	How to self-releasing? When the valve is closed, the pressure “ ΔP” at the upstream will push the plug to float down to the downstream and an offset between the center of the plug and the body chamber comes out, plug is against the downstream body wall tightly so a gap at the position of“ 1” might come out which forms a connecting cases between the body chamber and upstream pipe and the abnormal pressure increasing in the body chamber relieve to the upstream of the pipe.
	How to get pressure balance A ball/spring check 1) and a balance hole 3) are set up to give “ΔP” on the top and bottom of the plug both. An adjustable device is set up to make up the worm for on-off operation. Formula: Pdown =( ΔP+Pg)*A1 + ΔP*A3 +G; Pup = (ΔP+Pa) * A2 + ΔP*A4; Pg means the pressure given to the plug down by the high pressuregrease; Pa means the pressure given to the plug up by the adjustable stub. G means Gravity of the plug A3-A2＜A4-A1, so A3+A1＜A4+A1, if there aren’t Pg, G and Pa, the plug has the trend of going up and get much tighter but breaking torque would be increased so much, to get a balance point and make grease onto the plug surface easier, a 10.0 MPa pressure for the grease injection is given, which might be balanced by the adjustable stud.