Steam

inlet

7.14.1

Cold

water

inlet

13

Material

Operation

The mixing valve employs a piston to lift and open the steam valve.

The piston is lifted by the cold water supply. If the cold water

supply stops the piston will fall, closing the steam valve. To sustain

this design integrity the piston must move freely. Scale build-up will

prevent movement and regular maintenance must be carried out to

ensure the valves safe operation.

2

21

3

4

6

18

19

5

Steam

inlet

Materials

No. Part

11

10

9

16

7

8

20

Cold

water

inlet

17

Hot water outlet

Range

The 1⁄2" and 3⁄4" valves are primarily intended for use in

hosedown stations, washing down plant e.g. The food and beverage

industries.

See TI-P157-06 on steam/water mixing stations and TI-P157-05

for the hosedown gun, hose and hose rack.

High capacity 1" and 11⁄2" valves are intended for fixed installation

i.e. Periodic filling of tanks, therefore no hoses or guns are available.

Temperature/pressure ranges

All sizes will supply a mixed water temperature in the range of

40° to 90°C. For sizing, see TI-P157-06. The valves are supplied

with three fixed loading springs which allows the valve to operate

over a wide range of steam pressures. The intermediate spring is

fitted as standard.

Sizes and pipe connections

1⁄2", 3⁄4", 1" and 11⁄2" screwed BSP (inlet and outlet)

Limiting conditions

body

valve plug

valve seat

steel

steel

PN16

10.3 bar g @ 184°C

Designed for a maximum cold hydraulic test pressure of 24 bar g

Body design condition

19 Washer

20 Bypass 'O' ring

21 Spigoted spring guide (1" + 11⁄2" only)

Maximum pressure

and temperature of inlet steam

Pipeline ancillaries

Hosedown stations

Steam/Water Mixing Valve - MkII

1" valve shown

TI-P157-08

ST Issue 10

12

Description

Design

The MkII Spirax Sarco steam/water mixing valve is designed to

provide hot water economically by blending steam and cold water

quickly to the required user temperature. The temperature can be

changed by turning the adjustment knob. As the valve is not

thermostatically controlled in order to maintain a

fixed hot water

temperature the cold water pressure and flowrate must be

constant. The installer must ensure that the Local Water Board

Regulations are adhered to, with regard to direct use of mains

water supply. MkII valves were supplied from 2002 onwards.

1

14

15

Bronze

Stainless

Bronze

Bronze

Bronze

Stainless

PTFE

Stainless

Brass

Stainless

Stainless

Glass filled polymer

Plastic coated aluminium

Viton

Graphite

Klingersil

PTFE

Polypropylene

Bronze

Stainless steel

Stainless steel

Viton

Local regulations may restrict the use of this product to below the conditions quoted.

In the interests of development and improvement of the product, we reserve the right to change the speci

fication without notice.

© Copyright 2011

1

Upper

2

Steam

3

Upper

4

Piston

5

Lower

6

Steam

7

Steam

8

Bypass valve

9

Screw

10 Knob retaining screw

11 Fixed loading spring

12

Temperature

adjustment knob

DN15 - 25

DN40

head

valve spring

body

steel

13 Body 'O' ring

14 'O' ring packing washer

15 Top gasket

16 Bypass valve washer

17 Wall bracket

18 Cap screw

1⁄2" - 1"

11⁄2"

steel

steel