Spirax Sarco - Catalogo Agosto 2017

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Upstream pressure bar

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DN15LC

DN15

DN20

DN25

DN32

DN40

DN50

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DN80

Capacities are given in cubic decimetres of free air per second (dm

/s). The use of the capacity chart can be best explained by an example.

Required, a valve to pass 100 dm

/s of free air reducing from 12 bar to 8 bar.

Find the point at which the curved 12 bar upstream pressure line crosses the horizontal 8 bar downstream pressure line. A perpendicular

dropped from this point shows that whereas a DN15LC valve will only pass 57 dm

/s and is therefore not large enough, a DN15 valve will

pass approximately 120 dm

/s under these conditions and is the correct valve size to choose.

For full details see the Installation and Maintenance Instructions (IM-P004-05) supplied with the product.

Installation note:

The valve should be installed in a horizontal pipeline with the direction of flow as indicated by the arrow on the valve body.

Example: 1 off Spirax Sarco DN32 SDP143 pilot operated pressure surplussing valve fitted with a red pressure adjustment spring and

having flanged EN 1092 PN40 connections.

SDP143 Pilot Operated Pressure Surplussing Valve with Cast Steel Body TI-P004-01 CH Issue 6

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