85 / 218
CYLINDERS
Area of negative chamber
S
t
=
π
*
(
D
2
– d
2
)
3,14 * (32
2
– 12
2
)
=
690
mm
2
4
4
Volume of positive chamber
V
s
=
S
s
* C
V
s
=803
[mm
2
]
* 200
[mm]
=160600
[mm
3
]
V
s
=
0,160
dm
3
Volume of negative chamber
V
t
=
S
t
* C
V
t
= 690
[mm
2
]
* 200
[mm]
=138000
[mm
3
]
V
t
=
0,138
dm
3
Amount of free air required to fill the volume of the two chambers
V
s
and
V
t
considering a pressure
p
s
=6
bar
and
p
t
=4
bar
:
Q
s
=
V
s
*
(
p
s
+1)
Q
s
= 0,160
[dm
3
] *
(6+1)
[bar]
=
1,12
Nl
Q
t
=
V
t
*
(
p
t
+1)
Q
t
= 0,138
[dm
3
] *
(4+1)
[bar]
=
0,69
Nl
Quantity of air necessary per min
Q
=
(
Q
s
+Q
t
)
* n
Q
= (1,12+0,69 ) * 10=
18,1
Nl
/
min
With a supply pressure in both chambers of 6
bar
, the amount of free air is:
Q
s
=
V
s
*
(
p
s
+1
)
Q
s
=0,160
[dm
3
] *
(6+ 1)
[bar]
=
1,12
Nl
Q
t
=
V
t
*
(
p
t
+1
)
Q
t
=0,138
[dm
3
] *
(6+ 1)
[bar]
=
0,96
Nl
Quantity of air necessary per min
Q
=
(
Q
s
+Q
t
)
* n
Q
=
(1,12+0,96)
*
10=
20,86
Nl
/
min
In the case of single-acting cylinders, the air consumption is limited to the positive chamber.
Q = ( Q
s
+ Q
t
) x n
Thrust stroke
volume x (P+1)
Pull stroke
volume x (P+1)
Cycles perminute
Thrust stroke
volume x (P+1)
Cycles perminute
Free air
consumption inNl
Fig. 38
3
83
CAMOZZI
>
CYLINDERS