Standard Design



 

Design Features

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 valveweight.

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 cornnut protecting the stud from being rusty guarantees the valves sealed easier and more humanistic.

6) The lifting Eye is designed for the size 8"or larger and the supporting feet is given for 6" or larger

Excellent Performance Functions

	Blow-out proof stem 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. A PTFE washer is given to reduce the friction while the stem against the shoulder turns.
	Combined independent seals for stem sealing & fire safe for body-cover 1) Flexible Graphite Packing for Stem Firesafe 2) Stick grease slot with an injection fitting for stem emergency. 3) A combination of a graphite gasket, a SS and a CS diaphragmcarries 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.

Positioning and locking device

The indicator with raised O/Cmarking and locking holes is castfor the valve operated with awrench.	The O/C marking raised on the cover of gear box and locking device is fixed on the input shaft for the valve operated with a gear.	The O/C plate with an arrowshowing the direction ofoperation is fixed onto the 2”square head by two rivets

Stress analysis to the body
To prevent the body from being deformed at high pressure is a hard task for the designer when he/she designs a heavy duty plug valves. FLOWTECH/VETZ company is using a kind of advanced soft program to analyze the body’s stress at high pressure to make out the deformation value. See below pictures, so as to seek a valid body-reinforced way.



How the inverted plug valve works and Why Select it?

	While the valve sets in open position turning the stem in a clockwise direction to close the valve. Robust metal-to-metal seats cope well with the solidimpurities that can run at high velocities in close proximity to the integral seating surfaces, particularly when the valve is opened against a high differential pressure Plug valves are the preferred choice for bypass and equalization on main gas pipelines by most major gas transportation companies
	Robust metal-to-metal seats have also high resistance to solids objects and lack of gap/cavity between plug and body ensure that particles do not become trapped between plug and body thus avoiding damage to the seats while closing the valve
	Large seating area further enhances the Super-H resistance to erosion The wide area maximizes the effectiveness of sealant, so that if the valve starts passing it can quickly be solved by injecting Flowtech Sealant, restoring the valve’s bubble tight shut-off capabilities without the need of valve overhaul Sealant can be injected with the valve in any position and also under pressure, making the valve in-line maintainable.
	Turning the stem in an anti-clockwise direction to open the valve, unlike in other valve designs, the seats are well protected from the line media This ensures that even if the valve is left open for long periods of time, its seating areas will not get damaged, thus ensuring good sealing and long valve life.

Why Select Flowtech’s Plug Valves?

Benefit ：
• Certainty of zero leakage sealing down the line, even with damaged metal seats
• Certainty of operation with low and consistent torque which is stable over long periods of time
• Minimal maintenance regime
• Full in-line maintainability even under full pressure and without any need of shut down
• Assured sealing to atmosphere

How It Is Achieved
• Precise seat mating procedures
• Effective sealant injection system combined with wide. see the point 4/2 of “design features”
• Pressure balanced plug as standard, with option of Protected
• PTFE or MoS2 Coating Anti Friction Treatment on plug and stem See below photos
• Precise factory set plug loading
• Provision for sealant injection for the seats. see the point 4 of “design features”
• Provision for stem packing re-injection
• Independent stem sealing design that can meet stringent fugitive emissions requirements See the point 2 of “design features”
• All pressure seals in fire safe metal or graphite


Sample Applications
Pressure balance lubricated plug valves made by FLowtech should be selected whenever bubble tight shut-off (zero leakage) is needed and there is a concern about seat damage due to valves being opened against a full deferential pressure and/or the presence of solids or impurities in the process medium

High Pressure Gas Isolation Bubble tight shut-off on one ofthe more searching medias	Kicker, Vent and Drain on Scraper Traps Tight shut-off combined with limited throttling capabilities	Slurry Isolation Extremely abrasive services, arobust valve with no cavities
Bypass Equalizing Valves To resist the erosion caused by full differential pressure openings on a transmission line, it will seal to protect the main line valve	Underground Storage Protected metal seating to resistimpurities and give zero leakageeven on the highest pressures.	Flow line Manifold Isolation Isolation ensured on high pressuredirty services.