Product Handbook 2026 - Volume 1

Size and pipe connections: Boiler house Bottom blowdown systems

2

DN15, DN20, DN25, DN32, DN40 and DN50

½", ¾", 1", 1¼", 1½", 2" Flanged EN 1092 PN40 Flanged ASME 300

For alternative connections to those stated opposite please contact Spirax Sarco.

Materials

No. Part

Material

No. Part

Material

17 Nut

BBV4_ Carbon Steel BBV6_ Stainless Steel

Carbon Steel

1

Body

18 Upper housing

Carbon Steel

2 3 4 5

19 Diaphragm

Plug

Stainless Steel + stellite

Reinforced NBR

2.11 2

20 Gasket

Seat

Stainless Steel + stellite

Reinforced Graphite

21 Vent plug

Seat gasket

Reinforced exfoliated graphite

Brass

22 Bolt

Seat retainer

Stainless Steel

Carbon Steel

23 Diaphragm plate

BBV4_ Carbon Steel BBV6_ Stainless Steel

Aluminium

6

Cover

24 Spindle

Stainless Steel

25 Lever stem

BBV__P PTFE BBV__H Graphite

Stainless Steel

7

Packing

26 Screw

Carbon Steel

8

27 Seal

Cover gasket

Reinforced exfoliated graphite

Polyurethane

28 Spring

Spring Steel

BBV__H Stainless Steel BBV6_ Other Carbon Steel BBV__H Stainless Steel BBV6_ Other Carbon Steel BBV6_ Stainless Steel Other Carbon Steel

29 Spring guide

9

Stainless Steel

Bonnet nuts

30 Connector

Stainless Steel

31 Lever

SG Iron

32 Axis

10 Bonnet studs

Stainless Steel

33 Roller

Stainless Steel

34 Spring graphite

Spring Steel

Actuator clamp nut

11

35 Elastic ring 36 Elastic ring

Carbon Steel

12 Gland nut

Carbon Steel

Stainless Steel

37 Washer

13 Scraper ring

Carbon Steel

PTFE

38 O'ring

14 Yoke

Viton

SG Iron

39 Spacer

15 Closed plate

Carbon Steel

Stainless Steel

40 Washer

16 Hex. head screw

Carbon Steel

Carbon Steel

Kvs values Valve size

DN15

DN20

DN25

DN32

DN40

DN50

Seat diameter (mm)

22

25

Kvs values

4.9

7.2

10

18

For conversion: Cv (UK) = Kv x 0.963 Cv (US) = Kv x 1.156

TI-P405-51 EMM Issue 6

Page 2 of 11

BBV Automatic or Manually Actuated Boiler Blowdown Valves DN15 to DN50

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