Air Inlet check valve

Air Inlet check valve

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CHECK VALVES and STRAINERS
CHECK VALVES and STRAINERS
PRODUCT FAMILY
PIPELINE PROTECTION
PIPELINE PROTECTION
Main features

The purpose of the Air Inlet Check Valve is to permit a high flow air intake into the pipe, in order to prevent negative pressure, the result of which would be damage to the sealing joints and a risk of the pipe being crushed. It provides a normal flow during pipe draining.

Generally speaking, the choice of the ND of the air inlet check valve is based on an admissible negative pressure in the pipe of 2 meters water column. We then apply a ratio between the air flow in L/s and the cross section of the passage of the air inlet check valve, in dcm2 equal to 1900.

This figure is constant whatever the ND for the air inlet check valve, since it is given by the maximum velocity of air input which is 1900 dcm/s, that is 190m/sec.

We obtain maxi. air input flow rates for a negative pressure of 2m/wc. to:

DN (mm)80100150200250300350400
L/s7921236278249457727111271514519782

When the negative pressure reaches 3, 4 or 5 m/wc, see table below:

DNAir speed in Subsonic modeAir speed in Sonic mode
mm118,4m/s157,5 m/s179,9 m/s191,5 m/s195 m/s
ELIGIBLE LOW BAR PRESSURE RELATING TO THE NATURE OF PIPE MATERIALS
-0,1-0,2-0,3-0,4-0,5
80595 L/s792 L/s894 L/s962 L/s980 L/s
100929 L/s1236 L/s1412 L/s1503 L/s1530 L/s
1502091 L/s2782 L/s3177 L/s3382 L/s3444 L/s
2003718 L/s4945 L/s5648 L/s6013 L/s6123 L/s
2505809 L/s7727 L/s8826 L/s9395 L/s9567 L/s
3008364 L/s1127 L/s12710 L/s13529 L/s13776 L/s
35011385 L/s15145 L/s17300 L/s18415 L/s18751 L/s
40014871 L/s19782 L/s22595 L/s24052 L/s24492 L/s
50023236 L/s30909 L/s35305 L/s37581 L/s38268 L/s

The air speed does not exceed 195m / s (speed of sound), this is due to a blockage of the mass flow at the level of the passage of the valve section. Note that the active section of the air passage is equal to the DN of the SNH valve, for example on a flanged valve DN 200 the air inlet section at the level of the valve seal marked N ° 3 is equal to 200mm.

Choice of diameter

Abacus enabling the choice of the ND of the air inlet check valve

Example:

For a 500mm pipe, with a tolerated negative pressure of 4m/wc, the maximum slopes on each side of the point in consideration being 8 cm/m, we choose the ND100. For a 500mm pipe, with a tolerated negative pressure of 2 m/wc, the maximum slopes on each side of the point in consideration being 8 cm/m, we choose the ND150.

Material and coatings

Item

Designation

Material

Coating

1

Body

S235 Steel

Protection Epoxy 200 microns oven baked 200¢ªC - RAL 5015 Blue

2

Clapper

S235 Steel

Protection Epoxy 200 microns oven baked 200¢ªC - RAL 5015 Blue

3

Clapper joint

NBR

4

Deflection cone

PVC

5

Bearing

Bronze UE7

6

Clapper spindle

316L St. Steel

7Inlet coneS235 SteelProtection Epoxy 200 microns oven baked 200¢ªC - RAL 5015 Blue
8Damper washerNBR

* Deflection cone (4) present from DN200

Compliance with standards

The Air Inlet check valve conforms to standard EN 1074 -1 & 4.

Minimum and maximum operating temperature: 0 to 70° C.

Minimum sealing pressure: 0.1 bar.

Permissible operating pressure (PFA) 10/16/25/40 bars depending on model.

Certificate of sanitary Conformity (ACS).

Installation

The air inlet check valve is installed in a valve chamber (see diagram) sufficiently ventilated by an upper grill cover.

It is recommended to fit a stop valve, which allows an eventual dismantling of the appliance, without having to close down the operation of the circuit.

It must be placed in a vertical position, at a height well above the pipe (see diagram) in order to prevent the sucking in of foreign matter into the pipe.

DN

E x E

H

80

1000 x 1000

2000

100

1000 x 1000

2000

150

1200 x 1200

2000

2001500 x 15002200
2502000 x 20002500
3002150 x 21002580
3502200 x 21502600