DKR-FL fittings (flat)

Straight fitting with flat seal and BSP thread

DKR-FL ( flat seal ) with flat seal ( without cone ) Straight fitting with BSP internal thread (inch). This type of fitting is quite unusual, unlike standard BSP fittings with a 60-degree cone in the case of the DKR-FL fitting, it does not have any cone. The fittings have a flat face on which the connection is sealed. This type of fitting is mainly found in Chinese-made machines and in pneumatics, pneumatic machines ( compressors etc ). Execution : free-cutting steel covered with zinc coating protecting against corrosion. An alternative to straight fittings are DKR-FL90 fittings: With flat seal and 90° bending angle, ideal for hard-to-reach places. DRF, Straight fitting with BSP flat seal, internal thread

What is a Flat-Seal?

A Flat-Seal is a type of flat seal that relies on the perfect fit of two flat surfaces meeting in a hydraulic connection. Unlike tapered seals, which use angled surfaces to create tightness, Flat-Seals are based on the contact of a wide, flat surface with a suitable gasket, usually made of elastomer (e.g., NBR, FKM) or metal. How does a Flat-Seal work? Sealing mechanism: In Flat-Seal type seals, the flat surface of the fitting or connector is pressed against the corresponding surface in the socket, which creates a tight connection. An additional element is often a sealing ring or o-ring, which fills microscopic spaces and protects against medium leakage. Stress reduction: Thanks to the flat contact surface, this seal reduces the risk of damage resulting from uneven force distribution, which increases the durability of the connection.

What are DKR-FL fittings?

DKR-FL fittings are hose crimping fittings with a flat seal (Flat-Seal), which provide maximum tightness in high-pressure systems. What are they for? DKR-FL fittings serve  connecting hydraulic hoses in industrial and mobile installations. Thanks to the use of a flat seal, they are widely used in places where traditional solutions may not guarantee sufficient tightness.

Other types of flat seal fittings 

In our offer, we also have fittings straight metric with DKL-FL flat seal. Another type of fitting with a flat seal are ORFS fittings meaning hose fittings with flat seal and American ORFS thread

DKR-FL C51 straight BSP hydraulic crimps with flat seal

DKR-FL C51 fittings (also occurring under the symbol DKR-F or C41 DRF) constitute a specialized group of hydraulic fittings intended for permanent crimping on flexible pressure hoses. Unlike traditional connectors with a 60° spherical cone, the DKR-FL version uses a flat face seal (Flat Seal). These elements are equipped with a swivel nut with a British Standard Pipe parallel thread (G), which prevents hose twisting during tightening to the connection socket. The design with a face contact seal guarantees exceptional leak resistance and is commonly used in demanding power hydraulics systems of construction, agricultural machinery, and industrial equipment.

Application and technical characteristics

Straight DKR-FL C51 fittings are designed for operation in high-pressure transmission installations. They are used to connect flexible hydraulic hoses with distributors, valve blocks, pumps, and actuators in systems where a connection with a flat sealing surface is required.

• Flat face seal (Flat Seal): The connection is sealed on a precision-machined flat contact surface, which minimizes the risk of leakage during sudden pressure spikes and vibrations.
• BSP parallel thread (G): Inch threads compliant with the British Standard Pipe in the range from 1/4" to 1.1/2".
• Pressure strength: Depending on the nominal diameter (from DN06 to DN40/DN50) and the type of hose used, the fittings transmit operating pressures in the full range of power hydraulics operating parameters.
• Durable steel construction: The elements are produced from 11SMnPb37 free-cutting steel covered with a zinc layer in white passivation. Stainless steel versions are available upon special order.
• Media compatibility: The fittings are adapted for failure-free transmission of mineral oils, synthetic oils, water-oil emulsions, and HFC fluids within the operating temperatures defined by standards.

Why choose HYDRON components?

The DKR-FL C51 fittings supplied by HYDRON are manufactured while maintaining rigorous dimensional tolerances. Careful machining of threads and the perfectly smooth contact surface of the fitting face eliminate the risk of deformation and micro-leaks. The applied galvanic coating effectively protects components from corrosion in environments exposed to moisture and chemicals. A correctly crimped fitting ensures long-term operation of the hoses under high load. To make a complete pressure hose, we recommend matching crimp ferrules and professional hose crimping machines from our offer.

Technical specification

Frequently Asked Questions (FAQ)

How does a DKR-FL fitting differ from a standard DKR fitting?

A classic DKR fitting seals on a 60° cone socket using a spherical seat. The DKR-FL (C51) fitting is equipped with a flat face and requires a flat seal. Both types have a BSP inch thread, but require completely different connection sockets.

What threads does the DKR-FL C51 fitting work with?

Fittings from this series have internal British Standard Pipe parallel threads (marked with the letter G), commonly used in European hydraulic machines and equipment.

Are DKR-FL fittings also available in angled versions?

Yes. We offer straight C51 versions, as well as 90° angled crimps (marking C52) and 45° angled versions (marking C55) with a flat seal.

How to correctly install this fitting on a hose?

The installation of the DKR-FL fitting is carried out by seating the tail part inside the hose and crimping a suitably selected steel ferrule using a hydraulic hose crimping machine.