SK780X Pressure Differential By-pass Balancing Valve is a diaphragm type of hydraulic control valve driven by the hydraulic pressure within the piping system, widely applied in HVAC system for guarantee of flow stability in the air conditioning, refrigeration and heating system and pump working. The valve prevents the effect on the other pipe branches when there is fluctuation on one branch by balancing of pressure in the radiant and distribution water manifold, thus to protect the efficient and safe working of the refrigeration set or heating set.

◔Operational principle

SK780X Pressure Differential By-pass Balancing Valve is composed of pressure balancing pilot valve, needle valve (or ball valve), mini strainer and ball valve, etc.

SK780X Pressure Differential By-pass Balancing Valve is installed between radiant and distribution water manifold (water supply and water return). Water flow enters continuously from water supply duct to the valve inlet and then to the upper cavity room (2) through needle valve (1) (or ball valve). Pilot valve (3) is connected to the water supply duct and return duct by guide tube (4) and (5) to sensing of the pressure difference and adjustment of the opening position of the pilot valve accordingly. When the pressure difference is large, pilot valve opens broadly, the pressure inside upper cavity room (2) declines and the basic valve opens broadly. As result the water flow between the supply and return duct increase and the entire system gets balanced. When the pressure difference is small, pilot valve (3) turns to close at the pressure of the spring, the pressure inside upper cavity room (2) increase and the basic valve turns to close. As result the water flow between the supply and return duct decreases and the entire system also gets balanced.

◔ Property and advantages

• Driven by pressure of pipe system, work automatically with energy of pipe system to achieve energy conservation and environment protection.

• Controlled by the pilot valve, lower energy consumption, achieve accurate pressure reducing results, have function of stabilizing pressure after the valve.

• Dual cavity design, with functions of fully opening and fully closing. Slow shut causes no pressure fluctuation, and the diaphragm with support is well protected.

• Have internal orifice, connect bottom cavity and outlet of the basic valve, make sure stability of reaction to keep stability of pressure after the valve, avoid any vibration and noise.

• Channel with straight-flow, slight friction loss, no eddy flow and turbulent flow, cut down the damage of cavitation.

• Long pitch orientation design for stem move, stable and no gap resistance.

• Balanced automatically, big gap design on connection of disc and stem, disc is free on the vertical flat against stem, it can balance the tolerance from machining and sealing surface. Good connection without leakage. Achieve functions of both reducing dynamic pressure and reducing static pressure.

• Ductile iron castings with nodularity higher than 90%, foundry in house with advanced melting technology and strict quality control system, testing reports and testing bars can be supplied with order. Records and testing bars maintained for one year in the factory.

• Good corrosion resistance, with stainless steel, copper alloy, rubber made from DuPont and other rust- resisting material, fusion bonded epoxy coating both for interior and exterior surface of the basic valve. All the characteristics in accordance with ANSI/AWWA C550 and other international specifications like WRAS, NSF61.

SK780X

Notes for installation and debugging

• The valve has been finished initial debugging tests before delivery. Further debugging test is also suggested during using according to different set-conditions.

• Over review pressure meter of water knockout drum and water collector, adjust pilot valve (3) according to set-difference of pressure. Clockwise is for increasing the pressure difference and anti-clockwise is for reducing pressure difference when set adjusting screw on the top of pilot valve. When adjusting is done, fasten the lock nut. Then you'll got set-difference for the pressure no matter how the pressure of pipe system changes.

• Adjust needle valve (ball valve) can achieve different movement speed for the basic valve. Normally, it has been adjusted well before delivery. No further adjusting suggested if no special notice.