Spirax Sarco SGC40, Installation And Maintenance Instructions Manual

IM-P130-29 

 CMGT Issue 7

12

Fig. 2

Notes:

1.  Before actioning any installation observe the 'Safety information' in Section 1.

2.  Apply the appropriate grease to SGS40 stainless steel screwed units to avoid 

cold welding.

Warning

The gaskets used in these units contain thin stainless steel support rings which may 

cause physical injury if not handled and disposed of carefully.

Under certain conditions corrosive elements in the flow media can affect the inside 

face of the  window, particularly where caustic alkali and hydrofluoric acid are

present. Mica glass protectors must be used to protect the glass when the unit is 

used on steam applications or when the ph is higher than ph9 or when the temperature 

is above 150 °C with a ph greater than ph7 (see section 2.1).

Regular inspection of the glass to check for thinning of the window must be 

undertaken based on an assessment of your system. If there is evidence of thinning 

or erosion damage, then the window should be replaced immediately. Always wear 

eye protection when viewing the contents of the sight glass.

Reasonable steps should be taken to protect personnel from injury in the unlikely 

event that the window breaks.

Applications that incorporate sight glasses should have stop valves fitted on both the inlet 

and outlet. It is imperative that the upstream stop valve is closed first in order to prevent 

over pressurisation.

Sight glasses must be fitted on the outlet side of a steam trap in either a horizontal or 

vertical pipeline in accordance with the flow arrow on the body. 

Warning:

 when the optional 

visual flow indicator flap is requested for horizontal flow applications the hinge must be 

placed uppermost otherwise it will not work for the purpose intended - See Figure 2. Where 

the trap is a blast discharge type e.g. thermodynamic, the sight glass must be fitted at least 

1 m (3 ft) from the trap. This is to ensure that the glass is not subjected to thermal shock 

or pressure. 

Ensure access is available for maintenance purposes.

3. Installation

Hinged at the top