Rajkot, Gujarat, India
Our Products
The MASCOT CavFlo trim effectively minimizes cavitation damage to control valve components by controlling the location of vapour bubble implosion in an area away from metal parts.
Problem: Cavitation Damage
Cavitation is a two-stage process: First, as fluid velocity increases through the restriction at the vena contracta, the pressure of the flowing liquid drops below the vapour pressure causing vapour bubbles to form.
Second, as the flow enters the enlarging passageway downstream of the vena contracta, the velocity decreases. The resultant pressure recovery raises the fluid pressure back above the vapour pressure, causing the vapour bubbles to collapse or implode. The implosion of the bubbles on metal surfaces stresses and eventually tears away particles of the metal. Throttling in most globe valves occurs at the restriction created by the clearance between the valve plug and seat ring; therefore, both can be severely damaged by cavitation. In addition, imploding vapour bubbles near the valve body and adjacent piping can also cause damage.
The Solution:CavFlo Trim: MASCOT CavFlo trim utilizes a number of small, diametrical flow holes through the walls of the seat retainer. As the valve plug lifts off the seat, increasing pairs of holes are opened. Each hole admits a jet of cavitating liquid, which impinges in the center of the retainer upon the jet of liquid admitted through the opposing hole. The impinging fluid jets form a fluid cushion and an area of pressure recovery that cause the collapse of the vapour bubbles in the fluid stream away from metal parts.
Stepped holes are used to ensure orifice type flow rather than tube type flow through the retainer; thus, the vena contracta is established externally rather than inside the retainer itself. The turbulence of the impinging flow promotes the collapse of vapour bubbles at the center of the seat retainer, minimizing damage to valve trim.
The valve plug fits the retainer closely, controlling the fluid flow through the holes. Therefore, the fluid must be fairly clean to avoid sticking and galling problems between plug and retainer.
Multistage CavFlo:The CavFlo multistage cartridge may appear similar to other competitive designs because of its drilled holes and close-fitting cylinders but here the similarity ends. Rather than acting as a flow restriction, the drilled holes in the CavFlo multistage cartridge are used as expansion areas for the fluid as it enters from restrictive channels machined in the outside of all interior cylinders. This prevents the fluid recovery from occurring adjacent to a critical trim surface. Successive intersections of the restrictive channels result in additional pressure losses while expansion holes connected to the channels create a series of expansions and contractions that result in a series of pressure drops. This staged pressure drop eliminates cavitation in most applications and minimizes the energy of cavitation that may still occur in others.
No Clogging Design:Anti-cavitation valves are typically constructed with small flow passages that can become plugged by dirt or other debris in the fluid stream. Such devices usually direct the flow initially to the throttling plug before passing it through the restrictive device. This results in sticking and galling as dirt and other material become trapped between the sliding plug and the inside surface of the anti-cavitation device. On the other hand, CavFlo is designed with two important protective features to minimize such plugging problems: First, flow is first brought through the cartridge; contaminants too large to pass through the small outer channels are trapped at the outer-most stage of the cartridge preventing debris from traveling through the device to the throttling plug. Second, because the inner channels progressively become larger, small particles (which pass through the first set of channels) are easily passed through the rest of the cartridge. In the unlikely event that the cartridge does become plugged, it can be easily disassembled and cleaned as the cartridges are never welded together.
Today's modern process control systems need Position Transmitters and Limit Switches that deliver a high level of accurate position feedback.
The infinite resolution potentiometer in the XFlo Position Transmitter senses the exact position of a valve coupled with a two-wire transmitter and sends a continuous 4-20mA signal to a remote indicating device.
The XFlo Limit Switch Box houses two to four Micro-switches or Inductive Proximity Switches to indicate Open, Intermediate or Close position with redundant signal options.
The Position Transmitter and Limit Switch Box can be combined in a XFlo PTLS2 box to provide accurate 4 20 mA feedback as well as two positions (Open, Intermediate or Close) via its two auxiliary switches.
The Aluminium housing is compact and explosion proof, weather proof and dust proof.
The MASCOT MegaFlo trim effectively reduces the gaseous noise in control valves.
MegaFlo design is a result of extensive research and engineering study. Various principles have been incorporated into the trim design allowing it to be used in varied applications like chemical/petroleum plants, refineries, power plants, process industries, nuclear industries and wherever a highly effective noise reduction valve is required.
Some of the built in design features are:
MASCOT spring cylinder linear actuator is a powerful, high-performance pneumatic actuator, which provides positive throttling or on-off operation to pneumatic control valves. Uniquely designed compact sized cylinders actuators accept supply pressures up to 150 psi, making very high thrusts available in a relatively compact unit. The basic 4 sizes cater to almost 85% of a plants requirement hence reducing the inventory & cost of maintenance spares.
The MASCOT spring cylinder linear actuator is fully field reversible for air to open or air to close action without additional parts; a spring provides reliable fail-safe operation.
Air is supplied to both the sides of the piston by the positioner providing very stiff and precise movement along with very high frequency response
| Salient Features | Inherent Advantages |
|---|---|
| High thrust cylinder | • Operating pressure of 150 psi (10.3 Bar) permitting substantially higher thrust capabilities than diaphragm actuators. • Tighter valve shutoff |
| High Frequency Response | • Double-acting configuration responds quickly to signal changes. |
| Lightweight & Compact | • Substantially lighter and more compact than comparable linear diaphragm actuators. • Offers ease of maintenance. |
| Wide choice | • Four basic actuator sizes 25, 50 and 100 & 200 can handle thrust requirements for over 85 percent of valve sizes in a plant. |
| Least number of parts | • 33% less parts than diaphragm actuators. • Cost of wearing parts is 10% than compared to diaphragm actuators allowing low spare parts inventory and maintenance costs. |
| Excellent Positioning Accuracy | • Powerful pneumatic stiffness allows a high pressure drop without plug slamming onto the seat due to air volume between the piston and the bottom of the cylinder. |
| Low Air Consumption | • Cylinder design uses less supply air than comparable diaphragm actuators. |
| Longer Stroke | • Longer strokes provide better process control. Size 25 spring cylinder linear actuators have a 11/2-inch (38 mm) stroke, in contrast to a 3/4-inch (19 mm) stroke on a comparable linear diaphragm actuator. Larger actuators have similar comparisons; stroke lengths are available up to 24 inches. This increases the rangability of MASCOT Control Valves. |
| Field Reversible | • Failure mode is easily reversed without additional parts. Reduces inventory costs. |
| No Pressure Regulator Required | • Cylinder actuators easily handle air supplies up to 150 psi (10.3 Bar) without a pressure regulator and can be operated with as little as 30 psi (2.1 Bar). |
| Simple Maintenance | • Periodic maintenance is easy to perform since the spring cylinder actuator only requires the removal of three parts to access all internal parts |
High torque and pneumatic stiffness combine together in the MASCOT Spring cylinder rotary actuator. These characteristics are designed into a lightweight, rugged and compact assembly, making the MASCOT rotary actuator the first choice for quarter turn applications. The MASCOT rotary actuator is created for operating the DiskFlo high performance butterfly valve, VFlo Segmented Ball Valve, EFlo Eccentric Plug Valve, QuickFlo Full Bore Ball Valve or other applications requiring precision in rotary motion.
The MASCOT Rotary uses a rocking piston assembly for direct conversion of linear motion to rotary motion. The rocking piston assembly along with a splined shaft and lever eliminates any lost motion due to backlash.
It is a compact and light weight actuator which has many interchangeable parts with the Linear Actuator hence reducing the spare part inventory and maintenance costs.
Adjustable stroke stops prevent excessive rotation and reduce excessive torque on shaft. They also act as mechanical limit stops to mechanically limit the control valves travel for safety considerations
| Salient Features | Inherent Advantages |
|---|---|
| Air supply up to 150 psi | • Higher torques achieved • Stiff piston positioning and control • Higher pressure differential limits on valves |
| Rocking Piston | • Direct connection to shaft • Zero loss of motion between actuator and valve • Fewer wearing parts involved |
| Splined Shaft & Lever | • Zero transmission loss |
| Rugged, Compact & Lightweight | • Installs in limited space conditions • Easy maintenance • Meets seismic requirements for demanding applications |
| Low Friction Bearings | • Provides millions of cycles with minimum wear • This combined with direct linkages provided very low hysteresis |
| Field Reversable | • No extra parts needed • Fast and easy field reversal possible • No change of spring direction required |
| Fail-safe Spring | • Moves the actuator to failure position without the assistance of air pressure. |
| Air Purged Transfer Case | • Safe Operation • Prevents corrosion of linkages • External position indicator |
| Stroke Stops | • Adjustable stroke stops prevent excessive rotation and reduce excessive torque on shaft. • Act as mechanical limit stops to mechanically limit the control valve’s travel for safety considerations |
The DeFlo VSD integrates the precision and simplicity of a Control Valve into a Desuperheater to attain maximum turn-down, responsiveness and accurate control.
For the maximum efficiency the DeFlo VSD atomizes the cooling fluid at the vena contracta just downstream of the throttling point right at the injection point. The special design of the spray retainer ensures a hollow swirling cone pattern of the atomized fluid.
The total cooling water differential pressure is available at the throttling point hence optimizing the atomizing effect even further.
The integrated MASCOT DeFlo VSD:
The DeFlo Mini is one of the most basic type of Desuperheater which utilizes a MASCOT GFlo Globe Control valve as its cooling water control valve.
It consists of fixed jets arranged to face the steam flow direction through the periphery of the Desuperheater sleeve.
It works well in stable conditions where the steam flow turn-down is a maximum of 4:1.
The Stainless Steel sleeve acts as a thermal liner and is of the size of the steam pipe ID hence eliminating localized velocities created by many competitor designs.
For low turndown applications or in oversized pipes a venturi sleeve can be provided which creates local turbulence and velocity for effective mixing of the water with the steam.
