Connect Under Pressure Hydraulic Coupling | Hidroman
FFDP Hydraulic Quick Coupling for Connection and Disconnection Under Pressure
Hydraulic systems often require quick and reliable connections during equipment changes, maintenance operations and field service. When residual pressure remains in a hydraulic line, a conventional quick coupling may be difficult or impossible to reconnect, depending on its design.
Hidroman's FFDP series flat-face hydraulic quick couplings are designed for connection and disconnection under pressure within the applicable operating limits. Their flat-face valve design helps keep connection surfaces clean and is intended to reduce fluid loss during coupling and uncoupling.
An important feature of the FFDP series is its design, which allows the male coupling to be reconnected to the female adapter after disconnection under pressure, by overcoming the residual pressure remaining in the system under suitable conditions.
The correct coupling must be selected according to the operating pressure, residual pressure, flow rate, connection standard, fluid compatibility and temperature requirements of the application.
What Is a Hydraulic Quick Coupling That Connects Under Pressure?
A hydraulic quick coupling designed for connection and disconnection under pressure allows a hydraulic line to be connected or disconnected when residual pressure remains, within the manufacturer's specified operating limits.
This function can be useful for mobile hydraulic equipment, machine attachments and service operations where connections need to be changed efficiently. However, not every hydraulic quick coupling is suitable for connecting or disconnecting under pressure. The function must be explicitly supported by the selected model.
FFDP Series Flat-Face Hydraulic Coupling Features
The FFDP series features a flat-face automatic coupling design compatible with ISO 16028. Hidroman's product information identifies both connection under pressure and disconnection under pressure as supported functions.
Key features include:
Connection under pressure: Supports coupling under suitable residual-pressure conditions within the product's specified limits.
Disconnection under pressure: Designed to allow separation when residual pressure remains in the hydraulic line.
Flat-face valve design: Helps keep connection surfaces clean and is intended to reduce fluid loss during disconnection.
Manual locking mechanism: Helps reduce the risk of unintended connection or disconnection.
Reconnection capability: The design supports reconnecting the male coupling to the female adapter after disconnection under pressure, under suitable conditions.
These features do not replace the need to verify the maximum rated pressure, flow capacity and permissible residual pressure for the selected coupling.
FFDP Hydraulic Coupling Technical Specifications
Specification | Product information |
|---|---|
Series | FFDP |
Product type | Hydraulic quick coupling for connection and disconnection under pressure |
Valve design | Flat-face |
Compatibility | ISO 16028 |
Material | Free-machining steel |
Thread options | BSP; NPT or metric available on request |
Seal | Nitrile O-ring (NBR) |
Operating temperature | −30°C to +110°C |
Surface treatment | Galvanized with Chrome III passivation |
Heat treatment | Automatic male coupling |
Connection method | Push the male coupling into place |
Disconnection method | Pull back the sleeve |
Connection under pressure | Specified as possible on the product page |
Disconnection under pressure | Specified as possible on the product page |
Special options | Viton and a heat-resistant special spring; −30°C to +225°C option, polyurethane |
Technical note: The −30°C to +225°C range relates to special options and should not be interpreted as the temperature rating of the standard NBR configuration. Confirm seal and spring compatibility for the specific application. Maximum operating pressure, flow capacity, connection size and allowable residual pressure should be verified using the relevant technical documentation.
Benefits of Flat-Face Hydraulic Quick Couplings
Cleaner connection and disconnection
The flat-face design helps limit contamination entering the hydraulic circuit through exposed connection surfaces. This is particularly useful in systems where hydraulic fluid cleanliness is important.
Reduced fluid loss
Flat-face couplings are designed to reduce fluid spillage during connection and disconnection. Actual fluid loss depends on the coupling design and operating conditions.
Connection flexibility under residual pressure
A suitable FFDP configuration can simplify connection changes when residual pressure remains in a hydraulic line. This does not mean the coupling can be connected or disconnected at any pressure without restriction.
Additional protection against unintended disconnection
The manual locking mechanism helps reduce the risk of accidental operation. Correct engagement and locking should always be checked before the hydraulic system is operated.
Typical Applications
Subject to confirmation of the relevant pressure, flow and application ratings, FFDP-type couplings may be considered for:
Mobile hydraulic equipment and construction machinery
Industrial production equipment
Field maintenance and service systems
Machine attachment connections
Hydraulic equipment requiring frequent connection changes
Selected defense and aerospace applications, subject to the relevant approvals and technical requirements
These are general application areas, not a certification statement. Critical applications require separate confirmation of suitability and compliance.
How to Select a Hydraulic Coupling for Connection Under Pressure
Choosing the correct coupling involves more than matching the thread size. Consider the following criteria:
Operating and residual pressure: Determine the normal system pressure and the residual pressure present during connection or disconnection.
Flow rate: Check that the coupling meets the required flow and acceptable pressure-drop limits.
Connection standard: Ensure that BSP, NPT or metric threads match the mating component exactly.
Fluid compatibility: Confirm that the hydraulic fluid is compatible with the selected seal material.
Temperature range: Distinguish the standard NBR configuration from special Viton or polyurethane options.
Connection frequency and mechanical loads: Evaluate operating conditions, vibration and the expected frequency of coupling changes.
Locking mechanism: Check that the coupling is correctly engaged and locked before operation.
Even a coupling designed for connection under pressure must be used within its manufacturer-defined limits. Do not select a model without confirming its pressure rating and permitted residual-pressure conditions.
FFDP Couplings Compared with Standard Flat-Face Couplings
Not every flat-face hydraulic quick coupling can be connected or disconnected under pressure. Standard flat-face couplings may offer advantages in cleanliness and reduced fluid loss, but their pressure-connection capabilities vary by model.
Hidroman identifies the FFDP series as suitable for both connection and disconnection under pressure. Therefore, selection should be based not only on ISO 16028 compatibility and flat-face design, but also on the specific model's approved operating limits.
Hydraulic Quick Couplings from Hidroman
Selecting a hydraulic coupling requires an assessment of connection standards, operating pressure, flow rate, fluid, temperature and installation conditions.
Hidroman offers hydraulic quick couplings and connection components for a range of hydraulic applications. When requesting a quotation or technical assessment for the FFDP series, provide the required coupling size, connection type, operating pressure, flow rate and residual pressure during connection.
Contact Hidroman to discuss your hydraulic quick coupling requirements. Confirming the application parameters helps ensure that the selected configuration matches the system's technical requirements.
Frequently Asked Questions
What is a hydraulic coupling that connects under pressure?
It is a coupling designed to connect or disconnect a hydraulic line when residual pressure remains, within the operating limits specified by the manufacturer.
Can the FFDP series be connected under pressure?
Yes. Hidroman's product page identifies the FFDP series as suitable for connection under pressure. The allowable pressure and operating conditions must be confirmed in the technical documentation.
Can the FFDP series be disconnected under pressure?
Yes. The product page also specifies disconnection under pressure. This does not mean that disconnection is permitted at unlimited pressure.
Which thread types are available?
The page specifies BSP as the standard option, with NPT and metric threads available on request. The exact connection size should be confirmed before ordering.
What is the operating temperature range?
The stated standard range is −30°C to +110°C. Special options may be available for different temperature requirements; verify the exact configuration.
What are the maximum pressure and flow ratings?
These values are not specified on the available product page. Contact Hidroman or consult the product's technical documentation for confirmation.
Hydraulic Quick Couplings — general quick coupling range.
Hydraulic Quick Couplings: Reliable Quick Connections — coupling types and selection criteria.
Metric Multi Coupling — for applications requiring multiple connections at once. This product page specifies that it cannot be connected or disconnected under pressure.