Danfoss Safety relief valves Type SFA15,SFV20,SFV25 Safety valve introduction

SFV 20 - 25 are standard, back pressure dependent safety relief valves in angle-way execution, specially designed for protection of vessels and other components against excessive pressure.The valve is designed to meet the strict quality demands and safety requirements for refrigeration installations, specified by the international classification societies.

The valve is recommended as an external and internal safety relief valve in refrigeration plants. The spring housing is closed tightly to avoid

refrigerant leakage. The inlet flow diameters of the valves are:

• 18 mm ( 3 / 4 in.) for SFV 20, and

• 23 mm (1 in.) for SFV 25

The valves can be delivered with set pressures between 10 and 25 bar g (145 and 363 psi g). Standard pressure setting valves having "TÜV Pressure Setting Certificate" with each valve, are also available.

Danfoss Safety relief valves Type SFA15,SFV20,SFV25 Safety valve Features

• Applicable for the refrigerants HCFC, HFC, R717

(Ammonia), R744 (CO 2 ) within a

temperature range of –30°C/+100°C

(–22°F/+212°F).

• Classification: DNV, CRN, BV, EAC etc.

To get an updated list of certification on the

products please contact your local Danfoss

Sales Company.

Danfoss Safety relief valves Type SFA15,SFV20,SFV25 Safety valve 

Technical data

• Refrigerants

Applicable for the refrigerants HCFC, HFC, R717(Ammonia), R744 (CO 2 ) within a temperature range of –30°C/+100°C (–22°F/+212°F). Flammable hydrocarbons are not recommended.For further information please contact your local Danfoss Sales Company.

• Pressure

Pressure setting range: 10 - 25 bar g

(145 - 363 psi g). For further information please contact your local Danfoss Sales Company.The valves are designed for: Strength test:

43 bar g (624 psi g) Leakage safety: Same as set pressure

Important: The SFV safety relief valve is dependent on the back pressure (if the back pressure is higher than the atmospheric pressure, the opening pressure will be higher than stated set pressure).Special circumstances such as vibrations (which should be avoided) and oscillating pressure may require an increased difference between the operational pressure and the closing pressure.

• Pressure setting

The operating pressure of the plant should be at least 15% below the set pressure. This allows a perfect re-seating of the safety relief valve after having been activated.

• Temperature range

–30/+100°C (–22/+212°F)

Danfoss Safety relief valves Type SFA15,SFV20,SFV25 Safety valve Design

Connections

Available with the following connections: Outside pipe thread T (ISO 228/1) Welding fittings (DIN 2448)

Housing

Made of special steel approved for low temperature operation. Spindle and seat are made of stainless steel, to ensure precise operation even during extraordinary conditions. The gasket of the valve cone is made of a special cloroprene (neoprene) compound.

Installation

To ensure exact operation of the safety relief valve it should be installed with the spring housing upwards. If the valve is mounted as an

internal safety relief valve without any demand for exact opening pressure, the valve may be fitted with the spring housing in other positions. When the valve is mounted, it is important to avoid the influence of static, dynamic and thermal stress.

A very precise technique has been applied for the production of the seal. However, this seal can still be damaged, if dirt is blown from the pipe system into the valve. It is recommended that safety relief valves exhaust into the open air with a U-pipe filled with oil on the discharge branch, to prevent dirt from penetrating into the valve. It is also recommended that the valves be installed in pairs in conjunction with the double stop valve type DSV. For further information please see the DSV data sheet.

Re-calibration/servicing

In certain countries the authorities demand that the valves are checked at least once a year (see local rules).

Control/Identification

After adjustment of the set pressure at Danfoss,the valves are sealed. For that reason Danfoss can only guarantee correct operation, as long as the seal remains unbroken. All valves are provided with a metal plate with

the following information:

- Flow diameter

- Set pressure

- Date of production

- Production number

- Type approved code.

Transport/Handling

The valves are fitted with special protection covers and packed into purpose made transportation cartons.It is important the cover remains fitted around the valve until it is installed.To ensure the exact and precise operation of the valve it must be handled with care.