CHECK VALVES AND STRAINERS

Air Inlet check valve

Application

Sewerage Network protection

Network Protection

Product family

Pipeline protection

Technical design


80	10	260	470	500	360	550	330	22	RCA80LABH
100	10	284	560	550	450	600	413	26	RCB10LABH
150	10	350	780	760	610	1150	434	38	RCB15LABH
200	10	420	980	1150	825	1550	457	56	RCB20LABH
250	10	480	1200	1450	1010	1650	497	63	RCB25LABH
300	10	540	1260	1500	1110	1780	520	92	RCB30LABH
350	10	680	1310	1560	1280	1835	430	122	RCB35LABH
400	10	730	1420	1650	1410	2115	480	172	RCB40LABH
80	16	260	470	500	360	550	330	24	RCA80LAAH
100	16	284	560	550	450	600	413	28	RCB10LAAH
150	16	350	780	760	610	1150	434	40	RCB15LAAH
200	16	420	980	1150	825	1550	457	60	RCB20LAAH
250	16	480	1200	1450	1010	1650	497	67	RCB25LAAH
300	16	540	1260	1500	1110	1780	520	98	RCB30LAAH
350	16	680	1310	1560	1280	1835	430	132	RCB35LAAH
400	16	730	1420	1650	1410	2115	480	186	RCB40LAAH
80	25	260	470	500	360	550	330	26	RCA80LADH
100	25	284	560	550	450	600	413	31	RCB10LADH
150	25	350	780	760	610	1150	434	42	RCB15LADH
200	25	420	980	1150	825	1550	457	64	RCB20LADH
250	25	480	1200	1450	1010	1650	497	71	RCB25LADH
300	25	540	1260	1500	1110	1780	520	105	RCB30LADH
350	25	680	1310	1560	1280	1835	430	136	RCB35LADH
400	25	730	1420	1650	1410	2115	480	198	RCB40LADH
80	40	260	470	500	360	550	330	28	RCA80LAEH
100	40	284	560	550	450	600	413	35	RCB10LAEH
150	40	350	780	760	610	1150	434	52	RCB15LAEH
200	40	420	980	1150	825	1550	457	68	RCB20LAEH
250	40	480	1200	1450	1010	1650	497	79	RCB25LAEH
300	40	540	1260	1500	1110	1780	520	112	RCB30LAEH
350	40	600	1310	1560	1280	1835	580	145	RCB35LAEH
400	40	680						210	RCB40LAEH

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)	80	100	150	200	250	300	250	400
L/s	792	1236	2782	4945	7727	11127	15145	19782

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

DN	Air speed in Subsonic mode				Air speed in Sonic mode
mm	118,4m/s	157,5 m/s	179,9 m/s	191,5 m/s	195 m/s
	ELIGIBLE LOW BAR PRESSURE RELATING TO THE NATURE OF PIPE MATERIALS
	-0,1	-0,2	-0,3	-0,4	-0,5
80	595 L/s	792 L/s	894 L/s	962 L/s	980 L/s
100	929 L/s	1236 L/s	1412 L/s	1503 L/s	1530 L/s
150	2091 L/s	2782 L/s	3177 L/s	3382 L/s	3444 L/s
200	3718 L/s	4945 L/s	5648 L/s	6013 L/s	6123 L/s
250	5809 L/s	7727 L/s	8826 L/s	9395 L/s	9567 L/s
300	8364 L/s	1127 L/s	12710 L/s	13529 L/s	13776 L/s
350	11385 L/s	15145 L/s	17300 L/s	18415 L/s	18751 L/s
400	14871 L/s	19782 L/s	22595 L/s	24052 L/s	24492 L/s
500	23236 L/s	30909 L/s	35305 L/s	37581 L/s	38268 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	Item	Material	Material
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
7	Inlet cone	S235 Steel	Protection Epoxy 200 microns oven baked 200¢ªC - RAL 5015 Blue
8	Damper washer	NBR

* 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.