POK English catalogue (Complete)

POK France - ZI Les Guignons - 10400 Nogent-sur-Seine - FRANCE Tel: +33 (0)3 25 39 84 78 - Fax: +33 (0)3 25 39 84 90 - Email: export@pok.fr - Web: www.pok.fr 66 Anti-recoil elbows Some misinformed sales agents claim that their nozzles have an anti-recoil function and thus have a lower reaction force. This is not true. The reaction force of a nozzle is given by the formula F = ρQV (the laws of physics are the same for all) with: ρ = density of water Q = volume flow rate per unit time V = velocity of the water at the tip - The density of water is the same for everyone. - Reducing the speed of the water reduces the span distance and nobody is interested in a nozzle which has no range. - Reducing the flow remains the only option to decrease the reaction force. In conclusion, those who reported smaller reaction force of their fire nozzle cheat on flow! Q.E.D. The nozzle operator who wants to reduce the recoil force has in general five solutions: -1- Use a recoil elbow that allows a component of the force to press on the inclined hose (stiffened by pressure) and use the weight of the operator to balance another component, reducing by about 15% the effort required to balance the reaction force of the nozzle in action. -2- Sit on the hose, pulling the nozzle towards oneself, and positionned between the legs (with various variants of this position). -3- Switch to full spray. -4- Reduce the flow with the flow control ring. -5- Reduce the supply pressure of the nozzle, which reduces the flow rate and the speed.