CAL-VAC® Rupture Disc

Relieve ultra-low vacuum or positive pressure conditions with the highly accurate, bidirectional CAL-VAC rupture disc.

Our double-acting design allows the CAL-VAC to do the work of two rupture discs with just one installation point. It relieves low vacuum pressure (as low as 1 inwc) on one side, while slightly higher pressure is relieved from the other.

The CAL-VAC’s easy-to-clean flat seat design reduces product buildup, making it easier to meet FDA requirements.

Looking for the POS-A-SET rupture disc? Nearly identical to the CAL-VAC rupture disc, the POS-A-SET relieves ultra-low pressure in the positive direction – the inverse of the CAL-VAC’s ultra-low relief in the negative direction. Contact us if you aren’t sure which you need.

CAL-VAC® Rupture Disc

Two sides to the CAL-VAC rupture disc

As system vacuum approaches the burst pressure setting on the ultra-low vacuum side, a girdle is loaded until it deflects back past a knife blade assembly in the holder. As the girdle passes the knife blade, the seal is divided in a triangular pattern to relieve the vacuum.

On the higher-pressure side, the perforated metal top section, under tension loading, relieves pressure in the direction opposite the girdle. It incorporates CDC’s seven-hole pattern at the apex of the rupture disc dome. Together, the seven-hole pattern and six pre-cut sections create a non-fragmenting design.

Additionally, the top section’s pre-punched holes provide optimum flow through the disc when relieving ultra-low vacuum through the girdle.

CAL-VAC rupture discs vs. POS-A-SET rupture discs

The difference between the CAL-VAC and the POS-A-SET is the orientation of pressure relief components. The CAL-VAC relieves ultra low-pressure in the vacuum (negative) pressure direction, while the POS-A-SET Rupture Disc relieves ultra low-pressure in the positive pressure direction.

Both designs:

  • Relieve pressure as low as 1 inwc differential
  • Are dual-acting, providing both both positive and negative pressure protection
  • Can be made to meet 3A sanitary standards when used with a sanitary fitting holder assembly
  • Provide lower maintenance costs and greater reliability compared to a valve, increasing your system productivity
  • Do not include moving parts, eliminating the possibility of mechanical malfunction

Nominal Size Range: 3″ – 12″ (80 mm – 300 mm)

Burst Pressure Range:
Positive Pressure: 2 psig – 150 psig (0,138 barg – 10,3 barg)
Vacuum Pressure: 1 inWC – 115 inWC

Maximum Recommended Operating Ratio: Maximum Recommended Operating Ratio: Consult CAL-VAC literature

Seating Configuration: Flat seat

Service: Liquid or gas

BDI Alarm System Compatible?: Yes

ASME Code Symbol Stamp Available?: No

Materials not indicated or shown may be available by special design. Contact us for more information.

Industry Applications

Food & Beverage Processing
Food & Beverage Processing
Food & Beverage Processing

We understand that product purity and safety are critical in food-related industries, so we provide hygienic and aseptic vessels and piping to assure compliance with FDA and 3A requirements.

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