![]() |
![]() |
|
![]() |
![]() |
![]() |
|
||||||||||||||||||||||||||||||||||||||||||||||||
![]() ![]() |
||||||||||||||||||||||||||||||||||||||||||||||||
|
|
SUCTION TECHNOLOGY
|
|
|
What
is Vacuum?
The
earth's atmosphere exerts a pressure upon us, known as the atmospheric
pressure, which can be measured in a number of ways. At sea level the
standard pressures is 14.7 psi or 29.92" of mercury (Hg) or 760mm
of mercury (Torr). Because the barometric pressure varies, the above sea
level pressures are used as a reference point. When using the term "Vacuum", "negative pressure" "suction" etc. we mean a pressure that is lower than atmospheric pressure. |
|
|
Expression
and Unit
In
everyday speech there are many different expressions and units for
pressure below the atmospheric pressure. Some of the common units used in connection with vacuum and their inter relationship is given in the table below. |
|
|
Torr | mbar | HgV | HgA | psia | %Vacuum |
| 760 | 1013 | 0 | 29.921 | 14.696 | 0 | |
| 750 | 999.67 | 0.394 | 29.527 | 14.503 | 1.32 | |
| 700 | 933.03 | 2.362 | 27.559 | 13.536 | 7.89 | |
| 600 | 799.74 | 6.299 | 23.662 | 11.602 | 21.05 | |
| 500 | 666.45 | 10.236 | 19.685 | 9.668 | 34.21 | |
| 400 | 533.18 | 14.173 | 15.748 | 7.737 | 47.37 | |
| 380 | 506.5 | 14.961 | 14.961 | 7.348 | 50 | |
| 300 | 399.87 | 18.11 | 11.811 | 5.801 | 60.53 | |
| 200 | 266.58 | 22.047 | 7.874 | 3.867 | 73.68 | |
| 150 | 199.93 | 24.016 | 5.905 | 2.901 | 80.26 | |
| 100 | 133.29 | 25.984 | 3.937 | 1.934 | 86.84 | |
| 90 | 119.96 | 26.378 | 3.543 | 1.74 | 88.16 | |
| 80 | 106.63 | 26.771 | 3.15 | 1.547 | 89.47 | |
| 70 | 93.3 | 27.165 | 2.756 | 1.354 | 90.79 | |
| 60 | 79.97 | 27.559 | 2.362 | 1.16 | 92.11 | |
| 50 | 66.64 | 27.953 | 1.968 | 0.967 | 93.42 | |
| 40 | 53.32 | 28.346 | 1.575 | 0.773 | 94.74 | |
| 30 | 39.99 | 28.74 | 1.181 | 0.58 | 96.05 | |
| 25.4 | 33.86 | 28.921 | 1 | 0.491 | 96.66 | |
| 20 | 26.66 | 29.134 | 0.7874 | 0.387 | 97.37 | |
| 10 | 13.33 | 29.527 | 0.3937 | 0.19337 | 98.68 | |
| 7.6 | 10.13 | 29.622 | 0.2992 | 0.14696 | 99 | |
| 1 | 1.3329 | 29.882 | 0.0394 | 0.01934 | 99.87 | |
| 0.75 | 0.9997 | 29.891 | 0.0295 | 0.0145 | 99.9 | |
| 0.5 | 0.6664 | 29.9013 | 0.01968 | 0.00967 | 99.9342 | |
| 0.1 | 0.1333 | 29.9171 | 0.00394 | 0.00193 | 99.9868 | |
| 0.01 | 0.0133 | 29.9206 | 0.00039 | 0.00019 | 99.9987 | |
| 0 | 0 | 29.921 | 0 | 0 | 100 |
|
|
Conversion
formulas |
|
|
Torr (mmHg) | = 760-("HgV x 25.4) |
| = "HgA x 25.4 | ||
| = psia x 51.7 | ||
| = mbar x 0.75 |
|
|
"HgAbsolute | = mmHg/ 25.4 |
| = 29.92 - "HgV | ||
| = psia x 2 | ||
| = mbar x 0.0295 |
|
|
"HgVacuum | = 29.92 - (mmHg/25.4) |
| = 29.92-"HgA | ||
| = 29.92 - (psia x 2.036) | ||
| = 29.92 - (mbar x 0.0295) | ||
| = 'wc x 0.0735 |
|
|
"wc Vacuum | = Hg x 13.6 |
|
|
Please
note that a perfect Vacuum or Absolute Vacuum which correspond to 0 torr
or 760mm Hg is not possible on earth, no matter which Vacuum Pump is
used. |
| Our Product Range | |
| Feather Series : | |
| Non Electric Series : | |
| Wardcare Series : | |
| Tornado Series : | |
| Dual Power Series : | |
| Crown Series : | |
| Suction Accessories | |
| Suction Technology | |