Stop check valve plays a vital role in many industries to protect boilers and related equipments. These valves are designed with the aim to regulate the flow and to prevent backflow. This kind of valves performs two different tasks in one.

Introduction:

Stop check valve plays a vital role in many industries to protect boilers and related equipments. These valves are designed with the aim to regulate the flow and to prevent backflow. This kind of valves performs two different tasks in one. Maniks manufactures stop check valve since last thirty years.
Theory:
These valves are an altered rendition of the standard globe stop valve, which has the valve stem forever joined to the globe plate. In the stop check arrangement, the stem head skims in the globe circle. At the end of the day, they are by and large utilized as a globe valve to begin or stop the stream of the media, yet they additionally go about as a check valve to consequently close should weight be lost, in this manner averting reverse that could make harm hardware, for example, boilers or pumps.
Along these lines, having a stop check valve resembles having two valves in one. The inside circle, which isn't connected to the stem, executes as a lift check enabling it to unreservedly climb and down when the stem is raised to alter the opening and shutting. This controls the stream rate, yet when reverse happens, the detached plate works as a cylinder check and rapidly closes, subsequently averting reverse stream into the evaporator. If necessary, the stem can be physically brought for stream down to be halted or totally stopped.

Actual USE OF STOP CHECK VALVES:
These stop check valve are for the most part utilized as a part of energy plants, in applications, for example, heater course, steam age and kettle encourage water, turbine cooling, and starter water and wellbeing frameworks. They likewise are utilized as a part of different applications where channeling fashioners need to consolidate the properties of a globe and check valve. Such applications may incorporate high-temperature benefit, warm recuperation steam, high-weight security benefit, geothermal administration, utilities, oil generation and refining, wellbeing frameworks, shutdown cooling, and hydro­carbon preparing.
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In kettle applications, valves and boilers have been associated for more than 150 years. The valves utilized are critical to the point that the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code cover how valves ought to be utilized. The principal valves on a kettle yield line are generally stop-check valves, which are referred to here as non-return valves or evaporator stop valves. They are crucial when more than one evaporator is associated with the primary steam header, and they ought to be introduced in the pipeline between every kettle and the header. They likewise ought to be put with the goal that the weight in the heater is under the circle.
Another heater application is to utilize the stop check as a blow down valve. The blow down valve permits expulsion of abundance water from an evaporator, which is required once in a while. Blow down stop check valve is still being used on stationary boilers.
Stop Check Valve Design:

Connections:
• Butt-weld DIN (EN 10220) - ME 15 - 125 (½ - 5 in.)
• Butt-weld ANSI (B 36.10 Schedule 80), - ME 15 - 40 (½ - 1½ in.)
• Butt-weld ANSI (B 36.10 Schedule 40), - ME 50 - 125 (2 - 5 in.)
• Socket-weld ANSI (B 16.11),- ME 50 (2 in.)

Packing gland (MSCA-X):
• The "full temperature range" packing gland is the standard for the entire MSVL platform.
• This ensures perfect tightness throughout the whole temperature range: -60/+150°C (-76/+302°F).

Damping chamber:
• The chamber is filled with refrigerants (gas or liquid), which provides a damping effect when the valve opens and closes.

Housing:
• The housing is made from special, cold resistant steel.

Valve Cone:
• Valve cone with built in metallic stop - prevents damage to teflon ring in case of over tightening.

Spindle (MSCA-X):
• Made of polished stainless steel, which is ideal for O-ring sealing.

Features of Maniks Stop Check Valve:
• Applicable to HCFC, HFC, R717 (Ammonia) and R744 (CO2).
• Can be used in chemical and petro-chemical applications.
• Modular Concept :
o Each check valves housing are available with several different connection types and sizes.
o Possible to convert Stop check valve (MSCA) or check valve (MCHV) to any other product in MSVL family like regulating valve, stop valve or strainer. Just by replacing the complete top part.
• Fast and easy valve overhaul service. It is easy to replace the top part and no welding is needed.
• Designed to open at a very low differential pressure of 0.04 bar (0.58 psig).
• Designed with a built-in damping chamber preventing valve flutter in case of low refrigerant velocity and/or low density.
• Easy to disassemble for inspection and service.
• Internal back seating enables replacement of the spindle seal whilst the valve is active, i.e. under pressure.
• Optimal flow characteristics ensuring quick opening to the fully open position.
• Protection against pulsation by built-in damping facility.
• Housing and bonnet material is low temperature steel according to requirements of the Pressure Equipment Directive and other international classification authorities.
• Equipped with Stainless steel bolts. Max. working pressure :
o 52 bar g (754 psi g)
• Temperature range: -60/+150°C (-76/+302°F)
• Each valve is clearly marked with type, size and performance range.
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