Alfa Laval A49-42 Vacuum Breaker

Alfa Laval's A49-42 manual vacuum breakers provide relief from vacuum conditions in process lines. When used as a vacuum breaker, the A49-42 guards against siphoning and backflow, reducing the risk of product contamination and quality issues as well as protecting sensitive equipment. The valve's quick clamp-style assembly and simple design allows for the working parts for be rotated, converting the valve from a vacuum breaker to an air eliminator.

The A49-42 vacuum breaker is constructed of sanitary stainless steel, and is 3-A compliant for manual cleaning, making it a great choice for a variety of hygienic applications.

The A49-42 vacuum breaker is available with a two inch Tri-Clamp® connection.

  • Available in 2 inch Tri-Clamp connection
  • Line pressure positions the stem and o-ring
  • Valve is positioned at the high point of the piping
  • Not clean-in-place (CIP) capable, must be clean-out-of-place (COP)
  • 3-A compliant

A49-42 valves are used at the high point of a high-temperature short-time (HTST) pasteurization system to prevent contamination of pasteurized product due to backflow.

Models B44MP and A49-42 vacuum breakers are designed for line service only. They are not intended for use on tanks or vessels.


The A49-42's plug and o-ring assembly provide a seal against the base of the valve when the process line experiences normal, positive pressure. During vacuum conditions, the plug and o-ring drop down, allowing air into the system and eliminating the vacuum.

Standard Design

Model A49-42 is available in 2 inch Tri-Clamp connection only. It uses a teflon plug and o-ring design to provide a seal during normal processing. The valve features a small bell hood on top to direct any product blow-by down towards the floor.

Product Wetted Parts316
O-ringBuna, other options available
Dimensional Data

Overall Height: 1.625 inch

Product Resources

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A49-42 Vacuum Breaker (Alfa Laval)

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