PISCO RPV06 Series, Руководство пользователя, Страница: 23 / 30

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t = — × 2.3log —
V
S P
1
P
2
t
0
= t
1
+ t
2
+ t
3
+ …
t = — × 2.3log —
V
S P
1
P
2
t
1
= — × 2.3log — = 0.041min
20
58 101.3
90
t
2
= — × 2.3log — = 0.041min
20
57 90
80
t
3
= — × 2.3log — = 0.049min
20
55 80
70
t
4
= — × 2.3log — = 0.058min
20
53 70
60
t
5
= — × 2.3log — = 0.072min
20
51 60
50
t
6
= — × 2.3log — = 0.093min
20
48 50
40
t
7
= — × 2.3log — = 0.125min
t
0
= t
1
+ t
2
+ t
3
+ t
4
+ t
5
+ t
6
+ t
7
= 0.479min (= 28.7sec)
20
46 40
30
60
80
70
57
50
40
30
20
10
0
40 30 20 10 0 50 60 70 80 90 100
Exhaust speed
（
ℓ
/min
）
Final vacuum pressure （ kPa abs ）
RPV062-60
[50Hz]
[60Hz]
Selecting a Rotary Vacuum Pump RPV
■
To find the evacuation time from initial pressure to the end (final) pressure (targeted vacuum pressure) from
sealed space (tank), it is calculated by the following formula.
When carrying out the above calculation, since pumping speed: S of the rotary vacuum pump changes by
pressure ranges, first calculate each exhaust time :
t
1
,
t
2
,
t
3
,
and -- by dividing the pressure range, and then
calculate the sum : t
0.
Example) Use of RPV062-60 at 50Hz. Calculate the evacuation time to achieve from atmospheric pressure to 30kPa abs. for
the volume of 20 liters.
Calculate at each 10kPa precisely
Vacuum Pressure : Graph reading value of effective pump exhaust speed at 80 kPa abs
* Note: Above calculation is just an example. It can be calculated by a few dozen depending on an application.
t
: Evacuation (pumping) time (min)
V
: Volume of space (tank) (
ℓ
)
S
: Pumping speed (
ℓ
/min)
P
1
: Initial pressure (kPa abs)
P
2
: Final pressure (kPa abs)