Overview
Kadant Johnson's Series VB8 vacuum breakers are designed to prevent unwanted vacuum conditions in closed vessels or pipelines, protecting against contamination and equipment collapse. They feature fast-acting, tight-closing mechanisms with high capacity for air venting.

Specifications
The vacuum breakers are constructed with stainless steel components, including a retainer tube, ball, and spring, and feature an EPR seat for sealing. They are rated for pressures up to 300 psig and temperatures up to 365°F, with potential for higher pressures depending on size and materials.

Design and Functionality
The design ensures positive closing with low breakaway pressure, using a spring-loaded ball and soft seat for bubble-tight sealing. The system operates quietly and is resistant to corrosion, ensuring long service life.

Installation and Maintenance
Installation is straightforward with hex heads and standard NPT pipe threads. The vacuum breakers can be installed in vertical or horizontal positions using reducing bushings to prevent flow obstruction.

Testing and Reliability
Each unit undergoes rigorous testing, including endurance tests with steam and vacuum cycles, ensuring reliable performance over a million cycles. Every vacuum breaker is bubble-tested before leaving the factory.

Applications
Typical applications include protection of heating coils, textile dry cans, steam boilers, and heat exchangers. They are used to prevent vacuum conditions that could lead to equipment flooding or collapse.

Performance Data
The document provides detailed tables and graphs showing air intake capacities, dimensions, and differential pressures required to open the vacuum breakers. These are based on system connection sizes and installation positions.

Conclusion
Kadant Johnson's vacuum breakers offer a reliable solution for managing vacuum conditions in fluid handling systems, with easy installation, maintenance, and proven durability.