Erhard product range Non return valves Types: tilting disc check valveDN 150 - 1400PN 10 - 40 DN 80 - 600PN 10 - 40 swing check valveDN 40 - 800PN 10.

Erhard product range

Non return valves

Types:

tilting disc check valve DN 150 - 1400 PN 10 - 40

DN 80 - 600 PN 10 - 40

swing check valve DN 40 - 800 PN 10 - 16

reflux valve DN 40 - 300 PN 10 - 16

„ECR“ check valve DN 40 - 600 PN 10 - 25

ball check valve DN 50 - 350 PN 10

diaphragm check valve DN 40 - 400 PN 10

Sizes:

Pressure:

DN 40 - DN 1400

PN 10 – PN 40

NON SLAM nozzle“ type check valve

Erhard product range

Non return valves

Criteria for selection:

flow media (water, sewage)

size

pressure rating

headloss

space requirement

closing time (damping)

indication of position (visual, electric)

price

SWING type check valve

Non return valves

Design with external shaft – lever and weight

Design with internal shaft

SWING type check valveSWING type check valveDN 40 – 800 PN 10 -16

SWING type check valve

Non return valves

preferably for sewage (nearly full passage)

lever and weight (adjustability)

valve disc in stainless steel up to DN 300

with O-Ring seal

SWING type check valveSWING type check valve

Features:

Tilting disc check valve

Non return valves

with lever and weightdesign with hydraulic damping

DN 150 – 1400 PN 10 - 40

Non return valves

Tilting disc check valve

Features:

Tilting disc check valve

Seat ring of stainless steel

O-Ring for resilient seating

Non return valves

Tilting disc check valveDesign:

Non return valves

Non return valves

Principle of hydraulic damping cylinder

Valve in fully open position

Non return valves

Principle of hydraulic damping cylinder

Valve 45° closed

Valve closes without damping

Oil has free movement

Non return valves

Principle of hydraulic damping cylinder

Valve closed

Oil must pass the flow control valve

damped closing

Tilting disc check valve

Examples for use of hydraulic damping:

Non return valves

Tilting disc check valveHeadloss characteristic

Non return valves

Tilting disc check valve

Full opening device (opening cylinder)

Non return valves

Pneumatic cylinder

Valves is in fully open position also at low flow velocities

Low headloss

Energy saving

Tilting disc check valve

Recommendation for installation:

Non return valves

Tilting disc check valve

Arrangement of lever and weight:

Non return valves

NON SLAM Nozzle check valve

Features:

silent closing

low headloss

short face- to face dimension

resilient seated

inside enamelled

DN 80- 600 PN 10 - 40

Non return valves

DN 80 - 300 PN 10 - 40

Common features:

Internal body: zinc-free bronze

Outside: EKB epoxy Inside: vitreous enamel

Guide bushes: special plastic material

Guide rod, spring: stainless steel

ERHARD NON SLAM Nozzle Check Valve Types

DN 350 - 600 PN 10 - 16

Rubber-coated valve disc

Rubber-coated valve ring

v0

a = dv/dt

vRmax

T0

TR

TS

time t

For

war

d flo

wR

eflu

xFlow velocity

Non Return Valves: Hydraulic Characteristics

Flow retardation

0 m/s

In short, steep pipelines, the water column stops quickly, i.e. flow retardation a is high !

In long, flat pipelines, the water column does not stop quickly, i.e. flow retardation a is low !

0

0,2

0,4

0,6

0,8

1

1,2

1,4

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Flow retardation dv / dt in m / s²

Re

flu

x v

elo

cit

y v

in

m /

s

DIN

sw

ing

ch

eck

valv

e

Check valve with

slanted seat

Diaphragm check valve

Tilting disc check valve with

slanted seat and spring Nozzle check valve

ERHARD NON SLAM Nozzle Check Valve

Tilti

ng d

isc

chec

k va

lve

with

wei

ght-l

oade

d le

ver

Reflux Preventers: Dynamic Characteristics

Long, flat pipelines

Short, steep pipelines

Waterhammer:

Max waterhammer according to formula of „Joukowsky“

p

av

g

= max. waterhammer (m WC)

= surgewave velocity in water ( = 1200m/s)

= change in flow velocity (m/s)

= acceleration of earth (m/s²)

g

vap

Non return valves

Calculation of the max. waterhammer at different reflux velocities

)(12281,9

11200WSmp

)(2481,9

2,01200WSmp

Non return valves

Reflux velocity – 1 m/s

Reflux velocity – 0,2 m/s

Reflux check valve

DN 40 – 300 PN 10 - 16body with epoxy – enamel or rubber liningbody with epoxy – enamel or rubber lining

water and sewage

with rubberlined disc

Non return valves

ball check valve

DN 50 – 350 PN 10DN 50 – 350 PN 10

for sewage

ball of steel rubber coated

epoxy coating

Non return valves

diaphragm check valve

DN 40 – 400 PN 10

for water

soft closing

Non return valves

„ECR“ check valve

DN 40 – 400 PN 10 - 25wafer type

for use in water

with NBR sealing

quick acting

Non return valves