Project Description

The Honeywell Pressure Regulator Team is assisting in the development of a different type of reference air pressure regulator for use on commercial airliners. Most of the controls and actuators on commercial airliners are pneumatically controlled. For pneumatics to function, they need to reference a specific amount of pressure. This is achieved through the use of a reference pressure regulator. The reference pressure regulator takes in different levels of inlet pressure and outputs at a constant pressure level.
Honeywell has been building upon a legacy reference pressure regulator design for the last 60 years.  They have slowly worked out inefficiencies and design flaws in this design.  However, their current design has inherent flaws which limit its overall performance. The job of the Pressure Regulator team is to establish a new solution to the reference pressure regulator.
Improving the regulator design would increase the accuracy of pneumatic controls on the aircraft, which could increase economy of the system and safety to the passengers. The economy would also be increased through the improved durability and longevity of the system leading to less replacement parts and maintenance. There are about 15 reference pressure regulators on B737, one of the most common commercial airliners in the world. For a large company such as Honeywell, with products produced on a large scale, the small decrease in maintenance or production cost can benefit the companies’ profits greatly.

The Pressure Regulator team was introduced to the project through the following project description provided by the sponsor, Honeywell.
“In Tempe Arizona Honeywell produces a line of Pneumatic Controls for use in aircraft. These controls take the form of valves that are used for controlling the temperature, pressure, and flow of pressurized air that is extracted either from the aircraft’s main propulsion engines, or from a smaller auxiliary power unit (APU). These valves run from small 3/8ths-inch line sizes up to 10 inches in diameter, an carry pressures from just above atmospheric to 600 psig, with temperatures running from -40F to 1300F. The extracted air is cooled and the pressure regulated, and is provided to various “user” systems including wig anti-ice and cabin pressurization and environmental control. Many of the world’s aircraft use valves produced by Honeywell, and most aircraft have dozens of these valves. Virtually every valve has a small on-board pressure regulator that serves some controlling function. The purpose of this project is to evolve and improve these pressure regulators.
The pressure regulators in question provide several functions. Some simply limit the pressure in the valve actuator for structural reasons, while others produce a pressure that is used as a reference for control (where other pressures are compared to that reference for the purpose of controlling some function). While it is not quite correct to refer to all of them as reference pressure regulators because they don’t all provide that function, it is common to do so, and since the design does not differ, we’ll follow that habit.”