Desuperheater VariFlow

Variflow Desuperheater

VARIflow series desuperheaters from Carraro offer an efficient solution for precise steam temperature control, providing excellent water atomization and high rangeability. They bridge the gap between simple mechanical sprays and more complex, high-performance systems, making them ideal for a wide range of applications without the need for auxiliary control valves.

This system gives you the following benefits:

Precise temperature control
High rangeability
No auxiliary valve required
Handles high pressure.

For sales or commercial inquiries please contact us at marine@insatech.com.

Efficient and Versatile Steam Control

The VARIflow series desuperheaters are engineered to provide precise steam temperature control with exceptional water atomization and high rangeability.

Designed to fill the performance gap between basic mechanical sprays and more sophisticated, expensive devices, VARIflow desuperheaters offer flexibility through a wide variety of nozzle combinations.

The integrated diaphragm modulating actuator, typically assisted by a positioner, ensures full control of water flow during the desuperheating process, eliminating the need for an auxiliary control valve.

Suitable for applications with no practical limitations on steam temperature and pressure, VARIflow can handle water pressure differentials of up to 80 bar without requiring a supplementary reducing valve in most cases.

Key Features of the VARIflow Desuperheater

The VARIflow desuperheater has several benefits. See some of them listed below:

Excellent water atomization for precise steam temperature control
High rangeability to meet a wide variety of application needs
Multiple nozzle combinations (variety in number and size) for tailored performance
Diaphragm modulating actuator with positioner for accurate water flow control
No auxiliary control valve required, simplifying installation and operation
Handles high pressure differentials (up to 80 bar) without needing a supplementary reducing valve
Applicable for various steam conditions with no practical limitations on temperature and pressure.

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Solutions for Diverse Industries

The VARIflow desuperheater are designed to deliver precise steam temperature control and efficient water atomization across a range of applications such as:

Process gases
Steam.

The various industries which the desuperheater is suitable for includes, but is not excluded to:

Marine
Oil & gas
General industry
Power.

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Best Practices for Efficient Desuperheating

Optimizing Steam Velocity:
Higher steam velocity at the injection point enhances turbulence and water mixing, improving desuperheating efficiency by reducing water evaporation time. Carraro recommends a minimum steam velocity of 8-10 m/s, which can vary based on service conditions. In cases of low velocity, a liner in the injection chamber may be required.

Nozzle Clogging Prevention:
To prevent nozzle clogging, installing a strainer near the water inlet is advised. Strainers with mesh sizes between 16-30 (0.5-1 mm openings) are recommended. Regular inspection and cleaning after plant startup ensure optimal performance.

Sensor and Pipe Distance:
Temperature sensors should be installed 10-20 meters from the injection point, depending on steam velocity and desired outlet temperature. Straight pipe runs downstream should be at least 5 times the injection chamber diameter (5xDNj), with larger distances for specific applications.

Minimum Pipeline Diameter:
The pipeline diameter must accommodate the spray head size. A spray head with a 60 mm stroke requires a minimum 6-inch pipeline, while a 90 mm stroke needs at least an 8-inch diameter.

Variflow Nozzle Details Carraro 1024 16X9

VARIflow Multiple Nozzle Spray Desuperheaters: Efficient Design and Performance

The Carraro VARIflow multiple nozzle spray desuperheaters are available with either 6 or 9 nozzles, arranged in overlapping columns to ensure a continuous change in uncovered discharge area as the piston moves. These nozzles can be customized with different capacities to suit specific applications, providing flexible flow characteristics.

The desuperheater features a cage-guided piston behind the spray nozzles, which controls the discharge area for optimal performance. The nozzle head is securely attached to the main body, allowing for flexible orientation of the cooling water inlet and spray direction. Each nozzle design incorporates advanced technology to minimize frictional losses and maximize atomization efficiency. The nozzle assembly—comprising a nozzle head, orifice, and nozzle cap—ensures water is evenly distributed and emitted as a fine, symmetrical spray, enhancing overall efficiency.

How does the VARIflow desuperheater work?

The VARIflow desuperheater receives cooling water through a flange located on the main body, directing it to the nozzle tube and onto the nozzle head at the opposite end. The piston, positioned at the lower end of the body extension pipe, regulates the flow by controlling the seat and the area of the nozzles exposed to the water. When the plug is in the closed position, no water reaches the nozzle head. As the actuator, responding to the temperature control system, pushes the plug down, the nozzles open progressively, adjusting the cooling water flow rate based on the required specifications.

For technical questions

Martin Søvind Jensen

Tel: +45 2761 4502

Email: Martin.Sovind@insatech.com

Write to Martin

For commercial inquiries

Astrid Mihut

Tel.: +45 5537 2095

Email: Marine@insatech.com

Technical Specifications
Function	Temperature control of the overheated water
Size	Water: 1 ”, 1 1/2”, 2 ”and 3” (DN 25, DN 40, DN 50 and DN 80)
Steam flange	3” and 4” (DN 80 and DN 100)
Steam line	4” to 40” (DN 100 to DN 600)
Connection	Flanges (ANSI and PN)
Pressure step	Max ANSI 2500, PN 25-400
CV	From 0.0055 to 21.15
Material	Valve body: Alloy steel Nozzle head: Stainless steel (AISI 410 and AISI 420)
Temperature	Max 570 °C (Steam side)
Number of nozzles per head	6 to 9
Rangeability	Up to 50: 1
Water volume	Max 50 m³ per. hour
Delta P	Min. Delta P: 1 bar(g) Max. Delta P: 60 bar(g) (standard) - 80 bar(g) (special execution)
Cooling	Max: Up to 7 °C above the saturation point of the outlet vapor

Product specifications and manuals

Brochure - VariFlow - Carraro
English | pdf

Download
Manual - VariFlow - Carraro
English | pdf

Download

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Carraro - Desuperheater VariFlow

Efficient and Versatile Steam Control

Key Features of the VARIflow Desuperheater

Solutions for Diverse Industries

Best Practices for Efficient Desuperheating

VARIflow Multiple Nozzle Spray Desuperheaters: Efficient Design and Performance