UK Product Handbook 2026 - Volume 1

Control systems Self-acting controls

4

Materials

1

1

4

4

5

5 3

3

7

14

6

8

8

13 12

2

2

16 15

7

4.5 29

KA31 and KA33 unbalanced trim

KB31 and KB33 balanced trim

No.

Part

Material

1 2 3 4

Body

Cast iron

DIN 1691 GG 25

Bonnet

Cast iron

DIN 1691 GG 25

Valve head

Stainless steel

BS 970 431 S 29

Valve seat ring

Stainless steel

BS 970 431 S 29

DN15-DN25

Mild steel

BS 1449 CS 4

5

Valve seat gasket

DN32-DN50

Reinforced exfoliated graphite

6 7 8

Return spring

Stainless steel

BS 2056 302 S 26

Stem

Brass

BS 2874 CZ 121

Bonnet gasket

Reinforced exfoliated graphite

Bonnet studs

Steel

BS 4439 Gr. 8.8

12

Bonnet nuts

Steel

BS 3692 Gr. 8

13 14 15 16

Bellows

Phosphor bronze

EN 12449 Cu Sn 6

Bellows gasket

Reinforced exfoliated graphite

Bonnet bush

Brass

BS 2874 CZ 121

Plunger

Brass

BS 2874 CZ 121

TI-P078-02 CTLS Issue 14

Page 3 of 5

KA31, KA33, KB31 and KB33 Cast Iron Self-acting Control Valves

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