NS  Two-Stages, cushioned closure check valve

Developed to eliminate pressure slam of check valves, frequently found in roof-tank filling pumps of high-rise buildings. It opens on pump start, and closes at controlled pace when the pump stops.

The NS valve is located at the pump discharge (or on the common manifold of the pumps outlet), and is fullyopened through normal operation of the pump.

When the pump stops, and flow rate drops to nil, the valve starts closing. But unlike a standard hydraulic check valve that closes slowly from full- opening to fullclosure, the NS valve closes fast (within 2-4 seconds, depending on it`s size) to approximately 20% of its fullopening stroke (“Fast closure period”). By this time the returning flow is reduced to a negligible value.

Then, the closure pace of the NS valve is decreasing to a slower, adjustable speed (“Slow closure period”). This restricted movement of the valve trim generates a non-slam seating.

The described procedure does not require any electrical command and interlink between the valve and the pump as the device is activated automatically by the hydraulic parameters of the system.

The Dorot Series 300 Pump Control Valve (’30-BC) is an automatic controlled valve, activated by the pressure of the pipeline. The valve is assembled downstream of a pump and will open and close slowly when the solenoid is energized\de-energized respectively, thus preventing surges caused by sudden pump start-up or shut-off. The valve will close instantly on power failure.

Optional Pump Control valve applications:

• BC/PS Booster pump control & pressure sustaining - Pump control and Back-pressure sustaining valve.
• BC/DI  - Booster pump control & differential pressure sustaining - pump control, maintains constant flow at varying suction conditions. 
• BC/FR Booster pump control & flow-control
• BC/PR Booster pump control & pressure reducing
• BC/CD Booster pump control with extended, dynamic closure (for long pipelines)

Installed on the pump discharge.

Eliminating pressure surges caused by rapid change of the pipe velocity.

Opens slowly on the pump startup, and closes at adjustable pace before shut-off.

The pump motor is then switched-off by an electric interlink with the valve.

The valve eliminates damaging surges caused by pump start-up and shut-off. The electrically activated valve gradually opens on pump start up, and slowly closes before the pump is switched off. The valve will automatically close drip tight in case of power failure. Optional Additions: Flow Rate Limitation, Extended Closure, Two Stage Operating, Pressure Reducing and Pressure Sustaining.

• No slam operation
• Exceptionally low losses at high flow conditions
• Simple and reliable design
• Easy installation and maintenance

The Dorot Series 300 Pressure-Sustaining (’30-QR’) activates by the pressure of the pipeline. The valve opens instantly when the pressure in the pipeline exceeds the safe level, thus relieving excessive pressure from the network. When the pressure returns to normal, the valve closes slowly, at an adjustable pace.

• Better performance:

- Regulates at a stable mode, regardless of valve-size, down to near-zero flow. Thus, eliminating the need for a special low flow plug-design (such as ‘V-port’) or a bypass valve.

- ‘Floating’, low-friction internal-trim design, guided by unique LPT® device.

• Increased reliability:

- All control ports are fitted with SST sleeves for preventing corrosion-blockage

- Pre-shaped reinforced diaphragm – for easier assembly and improved longevity.

• Reduced periodic inspection\maintenance labor:

- The control-trim is fitted with a self-flushing, inline control-filter.

- Easy in-situ adjustment and maintenance.

• Versatility:

- A standard and simple single-chamber valve design, provides smooth operation.  Conversion to a double chamber is a patented option.

The valve opens instantly when the pressure in the pipeline exceeds the safe level, thus relieving excessive pressure from the network. When the pressure returns to normal, the valve closes slowly, at an adjustable pace.

• No slam operation
• Simple and reliable design
• Easy installation and maintenance
• Low Resistance and high flow capacity
• Protection for sewage as well as clean water pumping systems

The valve opens instantly when the pressure in the pipeline exceeds the safe level, thus relieving excessive pressure from the network. When the pressure returns to normal, the valve closes slowly, at an adjustable pace.