Valve Design
Nozzleman Flow Control...
Why is it important in
fire ground operations?
Nozzleman Flow Control Benefits...
 Ability for nozzle operator to change
flow on demand
 Nozzle has ability to adjust to new
flow setting by itself
 Is simple and easy... like a car’s gas
pedal
 Does not affect stream reach (other
than flow change)
 Does not affect stream quality
What Flow Control is NOT!
Changing the nozzle opening manually
This requires change in pump pressure
Calling pump operator to change
pressure ?? psi
Gating a ball valve to reduce flow
Anything that does not react instantly to
provide a change in the flow
Difference in Valve Designs
Slide Valve Design
Ball Valve Design
Ball Valve Design
(Valve gated half way)
Primary Advantages of Ball Valve...
Simple and familiar design
Easily serviced by repair people with
commonly available parts
Can be used in break-apart nozzle
configurations
Disadvantages of Ball Valve...
Designed to be used fully opened or closed
Creates turbulence when partially open
Seats require regular replacement
Difficult to open under pressure
Valve seal area in normal direct water path
Can bind and tighten with age
Slide Valve Design
(Valve gated half way)
Primary Advantages of a Slide Valve...
Does NOT create turbulence when “throttled”
Is smoother and easier to open under pressure
Requires little to no maintenance
No seats to replace
Has greater durability
Valve seal area not in direct water path
Does not bind or tighten with age
Disadvantages of a Slide Valve...
Moves more easily than a ball valve which
increases possibility of accidental movement of
valve (without detents)
Is not commonly familiar to field repair personnel
Design does not work well with break-apart
nozzle and valve combinations
Can be more expensive than a ball valve