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Page 1: Erhard product range

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 1400PN 10 – PN 40

NON SLAM nozzle“ type check valve

Page 2: Erhard product range

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

Page 3: Erhard product range

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

Page 4: Erhard product range

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:

Page 5: Erhard product range

Tilting disc check valve

Non return valves

with lever and weightdesign with hydraulic damping

DN 150 – 1400 PN 10 - 40

Page 6: Erhard product range

Non return valves

Tilting disc check valve

Features:

Page 7: Erhard product range

Tilting disc check valve

Seat ring of stainless steel

O-Ring for resilient seating

Non return valves

Page 8: Erhard product range

Tilting disc check valve

Design:

Non return valves

Page 9: Erhard product range

Non return valves

Principle of hydraulic damping cylinder

Valve in fully open position

Page 10: Erhard product range

Non return valves

Principle of hydraulic damping cylinder

Valve 45° closed

Valve closes without damping

Oil has free movement

Page 11: Erhard product range

Non return valves

Principle of hydraulic damping cylinder

Valve closedOil must pass the flow control valve

damped closing

Page 12: Erhard product range

Tilting disc check valve

Examples for use of hydraulic damping:

Non return valves

Page 13: Erhard product range

Tilting disc check valveHeadloss characteristic

Non return valves

Page 14: Erhard product range

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

Page 15: Erhard product range

Tilting disc check valve

Recommendation for installation:

Non return valves

Page 16: Erhard product range

Tilting disc check valve

Arrangement of lever and weight:

Non return valves

Page 17: Erhard product range

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

Page 18: Erhard product range

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

Page 19: Erhard product range

v0

a = dv/dt

vRmax

T0

TR

TStime t

Forw

ard

flow

Ref

luxFlow 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 !

Page 20: Erhard product range

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

Ref

lux

velo

city

v i

n m

/ s

DIN

swin

g 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 ch

eck v

alve

with w

eight

-load

ed le

ver

Reflux Preventers: Dynamic Characteristics

Long, flat pipelines

Short, steep pipelines

Page 21: Erhard product range

Waterhammer:

Max waterhammer according to formula of „Joukowsky“

p

avg

= max. waterhammer (m WC)

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

= change in flow velocity (m/s)

= acceleration of earth (m/s²)

gvap

Non return valves

Page 22: Erhard product range

Calculation of the max. waterhammer at different reflux velocities

)(12281,9

11200 WSmp

)(2481,9

2,01200 WSmp

Non return valves

Reflux velocity – 1 m/s

Reflux velocity – 0,2 m/s

Page 23: Erhard product range

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

Page 24: Erhard product range

ball check valve

DN 50 – 350 PN 10DN 50 – 350 PN 10

for sewage

ball of steel rubber coated

epoxy coating

Non return valves

Page 25: Erhard product range

diaphragm check valve

DN 40 – 400 PN 10

for water

soft closing

Non return valves

Page 26: Erhard product range

„ECR“ check valve

DN 40 – 400 PN 10 - 25wafer type

for use in water

with NBR sealing

quick acting

Non return valves


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