Beaudrey - Spray-Water Systems

Various layouts are possible:

1. Each screen is fed by a dedicated pump
2. All screens are fed from a common header fed by one or more pumps
3. The screens are fed from the existing pressurized water source; no extra pump is needed if the pressure is sufficient (2.5 bars, at least).

In all cases, all debris in the water must be removed so as to avoid clogging the spray nozzles. BEAUDREY screens have a built-in, self-cleaning strainer. All other screens require strainers in the pipework.

BEAUDREY proposes various types of pumps:

• Horizontal, centrifugal pumps fed from an existing, low-pressure pipe (cooling water pump manifold). A motorized valve is required on the circuit. It is opened when the spray pump runs.
• Vertical pumps with motor above deck. For the relatively small flow rates required, they are expensive, complex and very sensitive to installation conditions.
• Fully-submerged or submersible pumps. Such pumps are well suited to the screen application. They can be easily lifted out for inspection and are relatively economical while very robust. The single-impeller type is to be preferred.
• Self-priming pumps. Very well suited for plants with a water level up to 3 m (10 ft) below deck. To be used only with the one-screen/one-pump layout as they are not suited for variable flows required with multiple pumps in parallel.

Butterfly valves are well suited for screen plants.

• Pump casing       
• For fresh-water applications: Cast iron  
• For seawater applications: AISI 316L or duplex stainless steel
• Pump impeller    
• For fresh-water applications: AISI 304L stainless steel
• For seawater applications: AISI 316L or duplex stainless steel
• Pump shaft        
• For fresh-water applications: AISI 304L stainless steel
• For seawater applications: AISI 316L or duplex stainless steel         
• Pipework              
• For fresh-water applications: carbon steel         
• For seawater applications: HDPE or GRP         
• Valve casing        
• In all cases: Cast iron with EPDM lining
• Valve obturator  
• For fresh-water applications: Cast iron with EPDM lining, AISI 304 or AISI 316 stainless steel  
• For seawater applications: Cast iron with EPDM lining, AISI 316 or duplex stainless steel 

Pumps should not run at a flow rate of less than 75% of their nominal flow.

Pumps should not be subjected to run out (maximum flow at no pressure)

Considering how important the spray-water supply is for the screening plant, it is advisable to install a sufficient back-up capacity (stand-by pump).

Pumps should never be stopped for periods longer than 72 hours to avoid corrosion and damage to sealing devices.