Check Valves are a category of products used in fluid systems to prevent return or back flow. Many systems are designed for flow to travel only in one direction, and the use of a check valve insures that this is the case. AVI offers several standard types of check valves, including poppet style; swing flapper (inline and bulkhead mount), and split butterfly styles.
Poppet style check valves offer a wide range of cracking pressures, and very low leakage. These are ideal for inline applications where a positive check is required. Inline flapper style check valves are ideal for high flow low pressure applications.
Bulkhead mount or clack style valves are used to control the movement of fluid between tank compartments, commonly used in fuel cells.
Split Butterfly check valves are typically used in line in high flow moderate pressure applications such as fuel transfer. These valves have a very low cracking pressure and can be designed to handle very high temperatures as seen in bleed air environments.
AVI has several different design approaches that are tailored to meet the specific application requirements. Application requirements for a given check valve include operating pressures, temperature, actuation or cracking pressure, closing pressure, flow requirements and leakage.
Seal selection is also critical to the valve’s performance. AVI offers valves with seals made from elastomeric compounds, carbon compounds, and metal to metal seats depending upon the specific application requirements.
Materials used in the manufacture of a check valve vary from aircraft grade aluminum to stainless steel and other high temperature alloys. Selection of materials is generally driven by the systems pressure requirements, but the media used in the system, temperature requirements, and the weight limitations of the system are all considered when applying an existing design or proposing a new or modified valve.
The ability to drain and pull samples from aircraft fuel systems is an important part of the fuel systems design. AVI has been designing sampling and drain valves for nearly 60 years. Many of the early valve designs were so well engineered they are still in use today.
Sampling drain valves are typically poppet style valves that allow for a small amount of fuel to be pulled from the tank during pre-flight safety inspections. These valves may be mounted inside an access panel or directly through the skin of the aircraft. The AVI Mission is to be the premier provider of fluid system components on a world-wide basis.
Drain and defuel valves may be a poppet style or a ball style. These valves are used primarily to drain the entire fuel system for repairs or maintenance. They are typically located inside an access panel, so lightning resistance is not normally a concern.
AVI also supplies remote actuated drain valves that can be used to drain tanks or in some cases to transfer fuel from one tank to another. These valves can be designed with a variety of fittings to fit most applications.
Relief valves, often referred to as safety valves, are designed to allow excess pressure to escape protecting the integrity of the system. Valves of this type can also be used to maintain or regulate the pressure within the system.
AVI offers many styles of relief valves for all aircraft systems including air, fuel, oil, and water. These valves are designed to operate at pressures from 0.1 to 5000 PSI.
Relief valves are manufactured from Titanium, aluminum, and stainless steel. If you have a special need, or are engineering a new system, AVI can help you specify the correct valve for your application.
Shut Off Valves
Shut off valves are designed to control the flow of fluid within the system. AVI offers shut off valves for use in water, oil, pneumatic, fuel, and hydraulic systems. These valves are typically either ball or poppet style.
A two-way ball valve is primarily a shut off valve offering open and closed positions. A three-way ball valve offers the ability to send the fluid to one of two different ports, or in some designs both ports with a closed option as well. Ball valves are one of the most free flowing valve types due to the limited internal obstructions when fully open.
Poppet style shut off valves are popular in low pressure applications where flow restriction is not critical and a lighter weight is desired. Poppet style shut off valves are also well suited to non-locking normally closed applications.
Designed for hydrocarbon fuel service, these inline solenoid shut off valves are manufactured in accordance with Specification MIL-V-8610 and drawing MS29527.
These valves are normally closed, and open when energized. These valves are designed to work at pressures up to 60 PSI, temperatures from -65° to 160°F, 18-30 Volts DC, and will flow up to 60 GPH (gallons per hour).
AVI also offers solenoid operated fuel sump drains. These valves are normally closed and will open when energized with 18-30 volts DC. These valves are for low pressure applications where a manually actuated valve may not be practical.
Vent valves are used to allow the pressure in the tank to balance while preventing the spillage of the fluid through the vent lines. These valves allow the free flow of fluid or air in or out of a chamber or tank until they close, usually activated by a float. During refueling, incoming fuel dis-places the air in the tank. The vent valve allows this air to escape through a designated vent path.
When the tank is full, the float valve closes preventing the fuel from escaping. These valves also allow air to re-enter the tank as fuel is consumed preventing dangerous negative pressure and potential fuel starvation. Vent valves protect the fuel tank from pressure damage due to expansion and contraction of the fuel due to changes in temperature. In some applications they incorporate measures to prevent the fuel from exiting the tank when the aircraft is inverted either during flight or in an emergency.
Positive-negative or thermal/pressure relief functions are incorporated in many of these valves to meet the requirements of today’s modern systems. Auto-valve offers a selection of float valves available for a wide variety of applications. If your application requires something special, Auto-Valve can design and engineer a solution. Contact our sales or engineering staff for more information.
Built to Print
Auto-Valve’s State of the art in-house CNC machining capabilities are available for our customer’s “build to print” machining needs.
Our advanced model shop is capable of rapid prototyping and our leading edge machine tools and lean manufacturing processes ensure your parts are delivered on time and of the utmost quality.
We also offer the ability to reverse engineer parts and systems, especially for military operations.
Click here to learn more about AVI’s engineering capabilities.