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Automatic RB® (Relief/Bleed) Valve

Automatic RB<sup>®</sup> (Relief/Bleed) Valve
Miniaturized design allows flush-mounting on Terra desiccators to eliminate clearance and breakage problems.
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Cat.# Price
Automatic RB® Valve 1600-60B $ 122
Automatic RB® Valve with exhaust fitting . . .
  • Cuts gas consumption and contamination inside a nitrogen-purged desiccator
  • Continuously bleeds off excess internal gas to maintain a safe positive pressure
  • Reduced size allows space-efficient mounting on each desiccator chamber, eliminates clearance requirements
  • Automatically discharges any sudden surge of incoming gas
  • Protects against accidental negative pressure by functioning as a check valve
  • Reduces system recovery time and increases system efficiency by up to 400% (see test data below)
  • Extends life of desiccator and glove box gaskets
  • Operates maintenance-free, with 100% reliability, to eliminate need for inspection of bleed valves

To ensure a safe, continuous internal positive pressure, Terra Universal recommends the Automatic RB® Valve for use in all sealed enclosures.

Automatic RB® Valve is Two Valves in One

The Automatic RB® Valve provides two crucial functions. During normal operation, it allows a continuous low-level release of gas to maintain a positive pressure of about 0.05" WC (water column). It also functions as a check valve to ensure that air and contaminants cannot enter the enclosure in the event of a momentary negative pressure.

Most important, it provides operator peace of mind. Its field-proven reliability guarantees that your cabinets are maintaining a safe positive pressure, even if they experience periodic increases in nitrogen flow. It is thus an ideal complement to Terra's Dual Purge™ System and other nitrogen control equipment. It also helps prevent the warping of doors and extends the life of seals.

Multiple Valve Installation Minimizes System Recovery Time

The Automatic RB® Valve provides all the features of our old one in a much smaller package—only .4375" x .4375" x 1.5" (11 mm x 11 mm x 38 mm). This compact size makes it feasible to install a separate Automatic RB® Valve on each compartment of a large desiccator. It also allows flush mounting along the front lip of Terra desiccators to eliminate clearance and breakage problems.

Automatic RB® Valve Offers Enhanced Protection, Lower Costs!

In a desiccator with one relief valve, contaminants and moisture are passed from one chamber to another on their way to a single outlet at the bottom of the cabinet. Not only do contaminants and moisture take a long time to leave the desiccator, but they also come in contact with more parts.

Installation of an RB valve in each compartment ensures that contaminants are quickly purged out of the same chamber into which they entered (see more information below). This multiple-valve set-up thus maximizes efficiency and minimizes exposure to humidity and contaminants.

For extremely critical moisture and contamination requirements, consider Terra's NitroPlex™ Module, which adds a nitrogen multiplex controller to a multi-chamber desiccator to allow optimal control of the storage environment.

The valve body is fabricated of styrene-acrylonitrile (SAN) resin that resists a wide range of process gases and chemicals. Comes installed on specified cabinets.

Increased Security in Glove Box Applications

Increased Security in Glove Box Applications

Terra's miniaturized Automatic RB® Valve is ideal for use in large, nitrogen-purged enclosures, such as glove boxes.

Its small size allows multiple valves to be installed in a glove box to provide safe pressure release. The graph at right plots the flow rate of incoming gas against the resulting positive internal pressure when a one cubic-foot enclosure incorporates one, two, and three Automatic RB® Valves. This information provides an indication of how to maintain safe pressure levels at varying flow rates.

Nitrogen Configuration
  Nitrogen Consumption Recovery Time
Fig. 1: 110 ft3 40 minutes
Fig. 2:
55 ft3 (100% improvement)
20 minutes (100% improvement)
Fig. 3:
15 ft3 (nearly 300% improvement)
10 minutes (400% improvement)

Dual Purge™/ NitroWatch Systems,  One Automatic RB<sup>®</sup> Valve Dual Purge™/ NitroWatch Systems,  Four Automatic RB<sup>®</sup> Valves NitroPlex™ System
Fig. 1:
Dual Purge™/
NitroWatch® Systems,
One Automatic RB® Valve
Moisture migrates through cabinet
Fig. 2:
Dual Purge™/
NitroWatch® Systems,
Four Automatic RB® Valves
Moisture migration eliminated
Fig. 3: NitroPlex™ System
Efficient moisture removal,
reduced N2 use

Terra's New Automatic RB® Valve: Less is More

The reduced size of Terra's new Automatic RB® Valve greatly enhances its application possibilities.

This valve is designed to begin opening up when the internal positive pressure reaches about 0.05" WC (water column). If the pressure continues to increase, the internal pressure of the chamber could reach a potentially dangerous level. The new design, however, makes it feasible to install several valves in a desiccator or glove box without sacrificing storage or working space. It also allows more efficient nitrogen purging, using Terra's advanced control systems.

The graph illustrates how desiccator efficiency is improved through the use of multiple valves and Terra's NitroPlex™ Module. See Figures below for system set-ups.

Reduced Nitrogen Costs, Enhanced Product Protection
To maximize the useful life of desiccator doors and door seals, Terra recommends that you install one Automatic RB® Valve per desiccator chamber, regardless of the flow rate. This setup ensures that any contaminants or moisture that enters a chamber when a door is opened will immediately be purged out of the desiccator—before it has a chance to migrate to other chambers.

In the second test (represented in Figure 2), an Automatic RB® Valve was included in each of the chambers. Only 20 minutes—and only half as much nitrogen—were required to bring the humidity level to the set point.

The final test case (Figure 3) included a NitroPlex™ Module, Terra's new multiplex nitrogen controller that monitors the humidity in each chamber independently and directs a high-flow purge only where it is needed. With this setup, the desiccator required only 10 minutes to reach the set-point—only .25 the time required in the first test. It consumed only 15 cubic feet (.42 m³) of nitrogen, a small fraction of the amount necessary to attain the set point in the first setup

Note: These results are meant to represent typical, not guaranteed, values.

RB Valve

Automatic RB® Valve with Exhaust Fitting

Operates similarly to the unit above, but includes1/8" NPT fitting on the exhaust port to allow connection of 1/4" (6 mm)-diameter tubing. Dimensions: 1" x 1" x 2" (25 mm x 25 mm x 51 mm). Material: cast acrylic.

Cat.# Price
Automatic RB® Valve 1600-60A $ 139
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