Spray
guns
Operating Manual
Page
18
of
36
©2020 enz® technik ag
30.03.2020Version 1.0
Reaction forces
The water jet discharging at high pressure causes a reaction force. This can be so large
that the spray gun can no longer be held securely. EU directives require the use
of shoulder supports as mandatory when working with a reaction force of more
than 150 N. If the reaction force is over 250 N, then hand-operated use is no longer
permitted.
Figure 3 below shows two examples.
Figure 3: Reaction force with straight spray guns
Example 1: With a nozzle insert with Ø 1.2 mm and 200 bar working pressure, the re-
action force is less than 150 N. Here, you do not need to take any additional measures.
Example 2: With a nozzle insert with Ø 3.0 mm and 140 bar working pressure, the re-
action force is greater than 150 N. The spray gun must additionally be fitted with a
shoulder support.
Determine the working pressure in [psi] based on the flow table on
Page 17.
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
2.2
2.4
2.6
2.8
3
3.2
3.4
3.6
3.8
4
0
20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360
ø
N
o
zz
le
i
n
se
rt
[
m
m
]
Working pressure at the spray gun [bar]
Reaction force [N]
Example 2
Example 1
With support
Without
support
Only with
mechanical
support
