The Pipeline and Hazardous Materials Safety Administration (PHMSA) reported that 17.1% of all gas transmission pipeline malfunctions were due to incorrect operation. Freezing temperatures can cause flowmeters, pressure transmitters, and temperature sensors to fail or provide false information to operators.
Heated enclosures are the answer to protecting delicate instruments and preventing system failures. This blog provides an overview of heated instrument enclosures.
What Is An Instrument Heated Enclosure or Protection Box?
An instrument enclosure, or O’Brien box, is a metal or hard plastic covering that surrounds the instruments like a protective shell. The inside is insulated and has a heater providing excellent freeze protection. A thermostat controls the heater for temperature maintenance and to avoid excessive heat problems.
The protection box is part of the winterization system. Winterization systems are crucial for refineries, petrochemical plants, and other processes to protect equipment and piping against solidifying or coagulating contents. System components include steam or electrical heat tracing for pipes, O’Brien enclosures, and other process heating.
Benefits of Heated Enclosures
Besides protection from freezing, temperature-controlled enclosures offer other advantages, including:
Temperature control – Precise temperature control requires the instruments to be neither too hot nor too cold.
Insulates against extreme temperatures – Heated enclosures protect against intense cold and high ambient temperatures.
Shields against dust and dirt – A sealed instrumentation cabinet protects components against dust and dirt.
Protects from water – Instrument enclosures keep out wind-driven rain which can cause short-circuiting. They also reduce condensation preventing corrosion.
Improved safety – Safe for use in hazardous environments and offer extra protection when people work around delicate instruments.
There are various types of boxes available, depending on the working environment.
Types of Heated Enclosures
The two primary types of instrument enclosures are full and partial. A full enclosure surrounds the entire instrument package, protecting against the effects of drafts, wind, rain, and dust. Partial enclosure systems protect only the process-wetted portions of a transmitter. A wetted part is any instrument that uses a liquid as part of its measuring system.
For example, O’Brien heated instrument enclosures specialize in full and partial boxes. Both types use a heater as part of the pump and pipe freeze protection system.
Factors to Consider When Choosing Heated Enclosures
Consider the following factors when choosing a custom equipment box heater or O’Brien instrument enclosure.
- Temperature range – Choose an enclosure suitable for the application and environment.
- Type of heating element – There are two types of heating elements – vertical and horizontal.
- Enclosure sizes – It must fit over the components and devices.
- Level of protection – Choose an enclosure that meets the required level of protection.
Choose a heated enclosure that is easy to use and maintain.
Keeping Equipment and Instruments Working Efficiently
Freezing temperatures can drastically affect how instruments work and lead to complete system failure. Protect your instrumentation by winterizing with heated instrument enclosures to counteract the effects of cold weather and other environmental factors. They also protect against corrosion and mechanical abuse.
Inspect the instrument enclosure regularly for damage, and keep the wiring dry and free from wear, especially in hazardous locations.
Powerblanket's equipment boxes keep your valves and manifolds from freezing in even the harshest outdoor environments.