Anti hammer automatic air valve for sewage Mod. SCA

The SCA guarantees the proper operation of pressurized sewage systems allowing the entrance of  large quantities of air in case of pipe bursting or draining phases  and a controlled air outflow  speed.

Construction and advantages

  • Large  lower body designed with strongly  sloped high walls  to avoid  grease and/or  other  material deposit, and it contains four fusion obtained nerves to guide  the stainless steel float.
  • Upper  body containing the AS device  protection cup against water  hammer effect during rapid filling phases.
  • Mobile block including a large AISI 316 stainless steel float, placed on the lower body and connected through  a  stainless steel  rod  to  the  obturator.
  • Anti Shock  automatism composed of a metallic disk with 2 or more small orifices,  a guide bar and a counteracting spring in stainless steel.
  • Drainage valve  for chamber control  and  draining.
  • Maintenance can  be  easily  performed from the  top without removing  the air valve from the pipe.


Operating principle

  1. Entrance of large volumes of air
    During pipeline  draining  or bursting  phases it is necessary to bring  in as much  air as the quantity  of out-flowing  water  to  avoid  vacuum conditions.
  2. Controlled air discharge
    The  SCA air valve  is provided  with a mechanism called AS. During vacuum conditions the mobile block is laid over the  diffuser,  the  antishock disk comes down pulling the stainless steel  spring  and  allows the  entrance of  large  volumes of air through  the main orifice to compensate for the vacuum effect.

For air flow performances of SCA please refer to the chart depicted on the next page.

Working conditions
Waste water 70°C/ 1
58 °F Max; Maximum pressure 16 bar/ 232 psi; Minimum pressure 0,3 bar/ 4.35 psi.
Technical features
Lower body, upper body and  cover entirely  made in ductile cast iron GJS  500-7,  internal and  external painted with epoxy  powder  applied using fluidized  bed technology.
Obturator in polypropylene
AS  guide bar  and  spring in stainless steel
AS disk  in brass
Float and  rod  in stainless steel AISI 316
Gaskets in NBR
Sealing seat in stainless steel  / bronze
Drainage valve in galvanized brass  or stainless steel