Page 4 of catalogue Air valves of Erhard GmbH & Co. KG

Air outflow and inflow capacities
The suitable valve size is selected on the basis of the actual working conditions. Air admission via the large orifice (emtpying the pipeline). The air flow rate Q is identical with the outflowing water rate.

Recommended limit values
Filling the pipeline During the closing process of the TWIN-AIR® Air Valve, for safety reasons the max. admissible water Hammer should not exceed P = 3 bars. This is based on filling the pipeline at a velocity of 0.25 m/sec.

Air capacity
For air capacities, see below diagrams: Air evacuation via the large orifice (filling the pipeline). The air flow rate Q is identical with the inflowing water rate. Air evacuation via the small orifice (under working pressure).

Extreme air rate demand
If one single air valve cannot comply with the specified outflow and inflow requirements, air Valves can be fitted in clusters. For large air inflow rates (valves larger than DN 200), ERHARD Disc Type Air Inlet Valves are the appropriate solution.

Recommended limit values
Emptying the pipeline The recommended air velocity when emptying the pipeline is Vmax.=80 m/sec. (referred to the clear air-inflow cross section).

Air outflow (large orifice)

Air inflow (large orifice)

1.5

Working pressure P (bar abs)

DN 100

DN 50

DN 80

1.4

0,6

0

/20

Working pressure P (bar abs)

DN 80

DN 50

DN 1

DN

0,7

1.2

1.1

0,8

1.1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3

0,9

Air outflow capacity Q (m3/s)
0,1 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 1,1 1,2 1,3 1,4 1,5 1,6

Air evacuation under pressure (small orifice Ø 2,5 mm) Internal pressure P (bar abs)
3

Air inflow capacity Q (m3/s)

2

1 2 3 4 5 6 7

Air evacuation capacity Q (m3/h)

Postfach 1280 · D-89502 Heidenheim Phone: +49(0 )73 21 3 20-0 · Fax: +49(0 )73 21 3 20-5 25 http://www.erhard.de e-mail: export@erhard.de
Data corresponding to the latest level of development, modifications reserved. Printed in Germany. 04/05 46029EN

DN

1.3

150

150

00

/20

0

Catalogue Page 4 of catalogue Air valves, Erhard GmbH & Co. KG

Page 4 of 4

A choice of products and services from the Erhard GmbH & Co. KG delivery programme: Slide valves Butterfly valves Ball valves Diaphragm shut-off valves ... You will find information about the complete product range in the Erhard GmbH & Co. KG catalogues.