Features and Benefits

• Line pressure driven – Independent operation
  ‍
• Mechanical flow stem
  - Field adjustable
  - No moving parts
  - No electronic components
  ‍
• Highly sensitive hydraulic pilot
  - Requires minimal valve-ΔP
  - Tight setting window
  ‍
• In-line serviceable – Easy maintenance
  ‍
• Double chamber
  - Moderated valve reaction
  - Protected diaphragm
  - No spring - Full opening
  ‍
• Flexible design – Easy addition of features
  ‍
• “Y” or angle, wide body – Minimized pressure loss
  ‍
• Obstacle free, full bore – Uncompromising reliability

‍

Major Additional Features

• Closing at pressure drop – 790-91
• Pressure reducing – 792-U
• Solenoid control – 790-55-M
• Electric override – 790-59-M

Operation

The Model 790-M is a pilot controlled valve equipped with an adjustable, 2-Way, high sensitivity, differential pressure sustaining pilot.

The pilot [1], senses valve differential pressure.

Should that pressure rise above pilot setting, the pilot opens, introducing upstream pressure into the upper control chamber [2], causing the main valve to begin an irreversible “close & lock” process. Opening and resetting the main valve requires manual intervention by means of the manual reset valve [3]. When differential pressure is below pilot setting, the pilot blocks upstream pressure from the control chamber, and the main valve remains fully open.

The manual test valve [4] enables simulation of burst conditions and valve response. After testing, reset procedure is required. The mechanical flow stem [5] enables adjusting the closing point, to meet various flow regimes.

‍

Pilot System Specifications

Standard Materials:

‍

Pilot:

Body & Cover: Brass or Stainless Steel

Elastomers: Synthetic Rubber

Spring: Stainless Steel

Internal parts: Stainless Steel

Diaphragm Covers: Fusion bonded epoxy coated Steel or Stainless Steel

Tubing & Fittings: Stainless Steel 316 or Copper & Brass

Accessories: Stainless Steel 316, Brass and Synthetic Rubber Elastomers

‍

 Notes

• Burst flow settings should be at least 25% higher than the maximum allowed system flow
• Recommended continuous flow velocity: 0.3-6.0 m/sec ; 1-20 ft/sec
• Minimum operating pressure: 1.0 bar ; 14.5 psi. For lower pressure requirements consult factory

‍

Typical Applications

‍

Burst Control Valves in a Network

Every water system is vulnerable to bursts, whether due to system problems or external mechanical damage. This illustration shows a reservoir feeding a downhill line with lower elevation consumers. In case of burst, each Model 790-M protects against flooding lower elevation consumers.

The Model 790-M, installed at the reservoir outlet, also protects against reservoir emptying.

‍

Typical Installation

‍

‍

Technical Data

‍

Size Range: DN40-900 ; 11/2–36”

‍

End Connections (Pressure Ratings):

Flanged: ISO PN16, PN25 (ANSI Class 150, 300)

Threaded: BSP or NPT

Others: Available on request

Valve Patterns: “Y” (globe) & angle, globe (DN600-900 ; 24”-36”)

Working Temperature: Water up to 80°C ; 180°F

‍

Standard Materials:

Body & Actuator: Ductile Iron

Internals: Stainless Steel, Bronze & coated Steel

Diaphragm: Synthetic Rubber Nylon fabric-reinforced

Seals: Synthetic Rubber

Coating: Fusion Bonded Epoxy, RAL 5005 (Blue) approved for drinking water or Electrostatic Polyester Powder

‍

How to Order

Please specify the requested valve in the following sequence: (for more options please contact us)

• Size
• Main model
• Additional features
• Pattern
• Body material
• End connection
• Coating
• Voltage & main valve position
• Tubing & Fittings materials
• Operational data (according to model)
• Pressure data
• Flow data
• Reservoir level data
• Settings

‍

‍

‍

‍

‍