The safety butterfly valves are used on hydroelectric plants, aqueducts and waterworks to: limit the damages on turbine plant caused by water excess velocity in the pipelines due to any reason; shut off the pipelines on pumping plants or penstocks, in case of failure of electric power, to avoid backflow towards the pump.

Range

The standard version is composed by a butterfly valve with bare shaft and an oleo-dynamic actuator that includes the counterweight and the oleo-dynamic cylinder.

Moreover are available other configuration:

• butterfly with bare shaft with oleo-dynamic actuator and paddle over speed detector with manual resetting pump;
• butterfly with bare shaft with oleo-dynamic actuator and electric resetting unit;
• butterfly with bare shaft with oleo-dynamic actuator and paddle over speed detector and electric resetting unit.

References of Standard version:

Material and coatings

Butterfly with bare shaft

(*) Insert before doing the coating (**) Screws over M18 in steel cl 8.8 Galvanized

Oleo-dynamic Actuator

The oleo-dynamic actuators are protected with epoxy powder.

On the oleo-dynamic actuator are present two limit switchers for the opening/closing position.

Dimensions and mass - Standard Version

Can be supplied also without counterweight, using the oleo-dynamic cylinder with double effect.

Weight and overall dimension can be changed in a presence of specific installation demand.

Standard Version PN10

Standard Version PN16

Standard Version PN25

Dimensions and mass - Version with paddle over speed detector and manual resetting pump

The length “L” is the minimum advised

Version with paddle over speed detector and manual resetting pump PN10

Version with paddle over speed detector and manual resetting pump PN16

Version with paddle over speed detector and manual resetting pump PN25

Dimensions and mass - Version with paddle over speed detector and electric resetting unit

The length “L” is the minimum advised.

The electric resetting unit is not shown because can be placed by the customer on his requirements.

Version with paddle over speed detector and electric resetting unit PN10

Version with paddle over speed detector and electric resetting unit PN16

Version with paddle over speed detector and electric resetting unit PN25

Dimensions and mass - Version with electric resetting unit

For overall dimension see par 2.2.1.

The electric resetting unit is not shown because can be placed by the customer on his requirements.

Paddle over speed detector

Version for manual resetting pump

Version for electric resetting pump

Settable intervention speed from 0,5 to 3 m/s

Y = 170 mm with Øe pipe ≥ 340 mm

Y = Øe/2 with Øe pipe < 340 mm

Pipe diameter: minimum 168,3 mm ; maximum 2000 mm

Maximum allowable pressure 25 bar

Applicable Standards

Hydraulic test

Every single butterfly valve is subjected to hydraulic final test with the purpose of verifying the accordance with the prescriptions EN12266 and EN1074:

• Body test at 1,5 time the PFA (open valve);
• Seat test at 1,1 time the PFA (closed valve).

Product test

Control of coating: test of thickness, holiday test, impact test, MIBK test.

Conformity to the standards

Product:

• EN 1074-1 and 2

Plant test:

• EN 12266
• EN 1074

Flanges dimension:

• ISO 5752 series 14

Flanges drilling:

• EN 1092-2
• ISO 7005-2

Suitability for potable water:

• Italian DM 174/04
• Conformity to foreign norms: KTW (Germany), WRC (U.K.), ACS (France)

Marking

On the body like EN19:

• Nominal diameter in mm (DN);
• Nominal pressure in bar (PN);
• Type of ductile iron;
• Manufacturer’s logo;
• Model code;
• Fusion date.

On the label like EN19:

• Nominal diameter in mm (DN);
• Nominal pressure in bar (PN);
• Maximum operating pressure (PFA);
• Closing direction;
• Model code;
• Manufacturing order, Order confirmation;
• Manufacturer’s logo.

On the disc:

• Nominal diameter in mm (DN);
• Nominal pressure in bar (PN);
• Type of ductile iron;
• Manufacturer’s logo;
• Model code.

Valve selection

To do the right dimensioning of butterfly valve it’s necessary to know the hydraulic parameters and also the configuration required:

• Standard version (bare shaft and oleo-dynamic actuator)
• Safety butterfly valve with paddle over speed detector and manual resetting pump (standard version + paddle over speed detector)
• Safety butterfly valve with electric resetting unit: - without paddle over speed detector; - with paddle over speed detector.

To balance the counterweight is necessary to know:

• Upstream operative pressure (with open valve)
• Intervention speed (standard from 0,5 to 3,0 m/s, for other configuration contact the technical-commercial office)

Outlining what we said:

- Data needed for butterfly valve dimensioning to be given by the customer:

- Data needed for safety system dimensioning to be given by the customer:

Hydraulic features

The head loss Δh are variable in function of valve open degree and can be calculated with the following expression:

∆h = ζ.v² 2.g

with ∆h = head loss [m], ζ= head loss coeff, v = nominal speed [m/s], g = 9,81 [m/s2]

The head loss coefficient can be estimated from this diagram:

Determinates the head loss Δh it’s possible to calculate the flow rate Q in m3/h with the following expression (the same expression can be used to, having the project flow rate Q, to determinate the head loss Δh without using the head loss coefficient):

Q = ∆h 10.2 Kv

in which 10,2 is a corrective factor in meters, and Kv is the flow rate coefficient in m3/h, determinable from the following diagram in function of valve open degree:

Otherwise it’s possible to calculate the head loss with valve completely open, having the project flow rate Q, in function of DN, using the following diagram:

Instructions for use

Storage

The butterfly valve will have to be held (if possible) in covered places, the most possible protected from the sun (maximum allowable temperature 70°C in accordance to EN 1074), from the rain and generally from the atmospheric agents. Moreover it will have to be avoided that the seal of the same air valves come to contact with powder or earth

Installation

The operative instruction for installation changes in order to the required configuration (with or without paddle over speed detector, with manual pump or electric resetting unit).

Before do the installation it is necessary to assure that no earth or powder are inside the valve or in contact with the seat. Do a complete manoeuvre of opening and closing. The installation on water pipe is the one with horizontal axis respect the pipe axis and with safety device on hydraulic right side, for other position contact the technical-commercial office. It’s recommended a dismounting joint for valve with DN superior to 150 mm.

In any case, for the installation, refer to specific installation and operating manual.

Maintenance

To guarantee the full efficiency of safety valve, it’s necessary to do periodically a maintenance and a simulation of release movement.

We recommend to do this control every six months and, in any case, before the start up of pipeline.

In any case, for the maintenance, refer to specific installation and operating manual.