Dripless Fuel Couplings
Worlds Smallest Dripless
Series DL02Y
Series DL04Y
Series DL06Y
Series DL08Y

DL series introduction paragraph

Battlefield International Inc. introduced the world’s first UAV-specific fuel quick coupling in 2003. This product group is appropriately named “EnduroLink™". Battlefield’s EL series EnduroLink™ has become the standard fuel coupling in the UAV industry and for good reason. During critical comparative cycle testing with fuel at temperature, our EL series EnduroLink™ series claimed the top position by a significant margin against an impressive list of fuel coupler manufacturers. EL series EnduroLink™ is designed to maintain integrity with mogas, avgas, diesel and JP8 fuel better than our competitors in sandy and dusty extreme-temperature conditions. Armed with lessons learned and maintaining each proven attribute of our EL EnduroLink™ quick connect series, we have uncovered a simple and unique dripless fuel coupling design. Our DL EnduroLink™ series enables connection and disconnection without any fuel loss even in situations where the fuel lines are pressurized.

Detailed DL EnduroLink™ Product Group Description

1. Flush Face Configuration

Our DL EnduroLink™ series coupler has no plug cavity, ensuring foreign objects cannot collect in either the coupler or plug when in the uncoupled state. This limits the risk of FOD introduction in unavoidable sandy and dusty environments. A simple wipe of the flush faces of the coupler and plug when sand or dust is present limits the introduction of unwanted particles into the fuel system.

2. Dripless Connection

Our signature EL EnduroLink™ clears away system FOD with the small amount of fluid loss expressed with each coupling or uncoupling procedure. Our DL series leaves only a film with minute fluid loss droplets when coupling or uncoupling. The DL EnduroLink™ sealing advantage becomes clear when fluid lines must be connected or disconnected near contaminable electronics.

3. Connecting and Disconnecting With Pressure

Our DL EnduroLink™ series enables connection with pressure or vacuum present in one or both fluid lines while ensuring no fluid or pressure loss occurs at any point during the connecting, connected, disconnecting or disconnected stages. When connecting, the coupler and plug seal between themselves first and only then are internal pressures allowed to flow through. When uncoupling, the internal line pressure is sealed off between the coupler and the plug and only then does the coupler and plug become disconnected. This happens fluidically and then mechanically. Coupling or uncoupling can occur with pressurized fuel in close proximity to circuit boards without danger of fuel spillage near any electronic components.

4. EnduroLink™-Similar Operation Process

The connecting and disconnecting function was designed to ensure the DL EnduroLink™ series perfectly matched our signature EL EnduroLink™ series without the need for any extra steps required of the operator. Anyone working with EL EnduroLink™ in the field can begin to use our DL EnduroLink™ series with the same procedure as before.

5. Three GFLT Seals

EL EnduroLink™ requires only three GFLT seals in total for the coupler and the plug. This simple, unique design eliminates potential leak paths. Most Dripless coupler designs require more seals and in addition often require friction-causing wear-rings. Our DL EnduroLink™ dripless series matches our theater proven EL EnduroLink™ design seal for seal, all while providing our customers with full dripless features and benefits.

6. Best Seal/Seat Design

All of our competitor’s dripless fuel coupler designs include high friction fixed diameter seal locations not conducive to extreme temperature fuel applications. Primarily this is due to seal swell allowances. The most failure resistant mechanical seal configuration for the fuel transfer market requires lifting a GFLT O-ring seal off a seat to open a flow path and pressing the seal back against the seat to reseal. By including a simple internal valve cartridge with our radical yet simple mechanical gripping system, we were able to provide our customers with all the benefits of dripless design in a configuration suited to extreme temperature fuel applications. Our DL EnduroLink™ series has only one seal that must perform inside two fixed diameters, however, this specific sealing area is configured exactly like our theater proven EL EnduroLink™ body seal/seat.

7. Dripless Without Increased Force To Connect

In order to offer a dripless design, heavier springs are required by our competitors to overcome the inherent friction required to eliminate the spaces where fluid collects inside the coupler/plug set. Most designs require wear rings and several seals in confined spaces that must wipe against one or two moving hard parts causing metal to metal-like frictional resistance. These general industry and even aerospace-specific dripless designs require more force to connect than standard double shut off couplers. Standard double shut off coupler designs may function adequately in a lab or a clean room, but fail quickly with dust or sand in the mix. Close tolerance high friction quick connects must be designed from the ground up for either extreme-cold or extreme-high temperature specific applications; or risk sticky or “held up” failed connections especially after multiple connection cycles. A specific design breakthrough discovered at Battlefield International Inc. has enabled our DL EnduroLink™ series to function with similar “lack of internal friction” as our EL EnduroLink™ series in both hot and cold temperature extremes. We are currently defining the low temperature limits for the DL series through extensive climate chamber testing.

8. Weight and Efficiency

Our DL EnduroLink™ series benefited from an exhaustive design process requiring all unnecessary weight and mass to be eliminated. This was done through careful material choices. Aluminum is used for most, but not all machined parts. In order to ensure a trouble free and lengthy product life, some specific parts are machined from heavy, nickel plated brass. Through exhaustive systematic experimental product development we determined how to limit the mass of the heavy brass while maintaining the superior wear qualities. Our resulting DL EnduroLink™ quick connect is an efficient, light weight product designed for a high cycle life.

9. Meeting EnduroLink™ Specifications

The DL EnduroLink™ series pressure range, along with most other relevant capabilities is identical to that of the EL EnduroLink™. The only application differences include a slight increase in the nominal flow of the DL EnduroLink™ over the EL EnduroLink™ and the temperature range which is currently being defined for the DL EnduroLink™ which may or may not meet the extreme cold temperature limits of the EL EnduroLink™. The DL EnduroLink™ can connect and disconnect under pressure without leakage whereas the EL EnduroLink™ cannot.