Description
Rongde RDFK-FS1 Flow Switch
Product Overview
The Rongde RDFK-FS1 is a single-flow hydraulic flow switch designed for flow monitoring within the RDFK valve remote-control system. Unlike a proportional flow sensor or analog transmitter, this device provides a discrete switching signal when hydraulic flow reaches its operating threshold. That makes it useful for straightforward confirmation of hydraulic circulation or actuator-related flow conditions where the control system needs a binary status rather than a continuously measured flow value. The published RDFK documentation identifies the FS1 specifically as the single flow switch, distinguishing it from the RDFK-FS double-flow version.
The Rongde RDFK-FS1 is specified for hydraulic service with a rated pressure range of 8–12 MPa and a rated flow capacity of 6 L/min. Its electrical interface is 24 VDC at 0.2 A, with a normally closed switch output. The published minimum operating flow is 0.15 L/min. HM32 and HM46 hydraulic oils are identified as compatible media, while the enclosure is rated IP56 for protection against dust ingress and water exposure under the applicable test conditions.
For marine or industrial hydraulic control equipment, the Rongde RDFK-FS1 should be evaluated as a discrete hydraulic monitoring component rather than as a conventional PLC analog-input device. Its signal can be brought into a controller, relay logic circuit, alarm circuit, or valve-control system, depending on the original installation. Replacement should match pressure, flow direction, switching behavior, electrical rating, hydraulic medium, and connection arrangement. A similar-looking flow switch with a different contact state or pressure rating is not an acceptable substitute merely because its physical size is comparable.
Product Introduction
A hydraulic control circuit does not always need a transmitter. Sometimes it needs a clear answer: is sufficient flow present or not? The RDFK-FS1 addresses that requirement with a normally closed switching output and a published minimum operating flow of 0.15 L/min.
For a hydraulic valve remote-control system upgrade or legacy replacement, the important checks are flow direction, switching state, hydraulic pressure, oil type, and 24 VDC electrical compatibility. Those details determine whether the switch will behave correctly in the existing control logic.
Key Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer / Brand | Rongde |
| Model | RDFK-FS1 |
| Product Type | Single Hydraulic Flow Switch |
| Application | RDFK Valve Remote Control System |
| Flow Type | Single flow |
| Rated Pressure | 8–12 MPa |
| Rated Flow Capacity | 6 L/min |
| Minimum Operating Flow | 0.15 L/min |
| Rated Voltage | 24 VDC |
| Rated Current | 0.2 A |
| Output Signal | Switch |
| Contact State | Normally Closed (NC) |
| Hydraulic Oil | HM32, HM46 |
| Operating Temperature | −15 to +60 °C |
| Protection Rating | IP56 |
| Communication Protocol | None; discrete switch output |
| Firmware | None |
| Installation | Hydraulic line / valve remote-control circuit; verify original mounting arrangement |
The manufacturer-style RDFK documentation specifies the FS1 as a single-flow switch and gives the above pressure, flow, electrical, environmental, and output characteristics.
RDFK-FS1
Major Features / Practical Advantages
Single-flow monitoring
The monitors a single hydraulic flow path rather than providing two-way flow supervision. This differentiates it from the RDFK-FS double-flow switch. In a valve remote-control circuit, that distinction can be important because the control logic may depend on detecting flow in one defined direction.
Normally closed switching output
The FS1 uses a normally closed switch output. That is a critical replacement parameter. If the existing controller or alarm circuit expects an NC contact, installing a normally open equivalent can reverse the expected logic and create a false healthy/fault condition.
For maintenance teams, this is one of the first items worth checking against the wiring diagram.
Hydraulic pressure capability
The published specification gives an 8–12 MPa rated pressure range. That places the device within a high-pressure hydraulic control environment rather than low-pressure instrumentation service. The replacement unit should therefore be checked against the actual hydraulic circuit pressure before installation.
Defined minimum operating flow
A published minimum operating flow of 0.15 L/min gives engineers a useful reference when assessing whether the switch can detect the expected hydraulic condition. It should not be interpreted as a general accuracy specification; this is a switching device, not a precision flow meter.
24 VDC discrete interface
At 24 VDC and 0.2 A, the electrical interface is suitable for conventional low-voltage control circuits, provided the connected load and switching circuit remain within the specified rating. The FS1 does not provide a 4–20 mA, pulse, HART, or digital communications output.
Marine-oriented environmental protection
The published IP56 rating and −15 to +60 °C operating range fit the type of enclosed hydraulic equipment where exposure to dust and water spray can occur.
That does not mean the device is automatically suitable for every marine classification requirement. If the switch is installed on a classed vessel, the complete equipment approval and installation requirements should be checked separately.
Related Products
- RDFK-FS — RDFK double-flow switch; monitors two-way hydraulic flow and should not be substituted for the single-flow FS1 without checking the control logic.
- RDFK-PS — RDFK pressure switch; monitors hydraulic pressure rather than flow.
- MSPC-05 — flow-control check valve used within the same RDFK hydraulic control ecosystem; performs hydraulic flow regulation rather than electrical flow detection.
- RDFK Valve Remote Control System — system-level hydraulic valve-control architecture in which the FS and FS1 flow switches are used.
- replacement flow switch — procurement description should retain the normally closed contact requirement and hydraulic specifications rather than matching only the model name.
FAQ
What is the Rongde used for?
It is a single hydraulic flow switch intended for flow detection within the RDFK valve remote-control system. Its output is a discrete switch signal rather than an analog flow measurement.
Is a flow transmitter?
No. It is a switching device. The published specification identifies a switch output and normally closed contact behavior. It should not be treated as a 4–20 mA flow transmitter or precision flow meter.
What voltage does the use?
The documented rated voltage is 24 VDC, with a rated current of 0.2 A.
What is the minimum operating flow?
The published minimum operating flow is 0.15 L/min. The rated flow capacity is 6 L/min.
Is the normally open or normally closed?
The FS1 is specified with a normally closed (NC) switch output. This should be confirmed before replacement because contact-state differences can directly affect hydraulic control logic and alarm behavior.
Can I hot-swap the ?
No hot-swap assumption should be made. This is a physical hydraulic switch rather than a plug-in PLC I/O module. The hydraulic circuit should be isolated and depressurized as required by the vessel or plant maintenance procedure before removal.
Does support firmware or configuration software?
No. It is a mechanical/electrical flow-switch device and has no user firmware, PLC program, Ethernet interface, or configuration software.
Can I replace with RDFK-FS?
Not without checking the hydraulic circuit and control logic. RDFK-FS is the documented double-flow version, while is the single-flow version. Their intended flow-monitoring arrangements are different.
What should I verify when purchasing a replacement?
Confirm the model marking, flow direction, 8–12 MPa pressure requirement, 6 L/min rated flow capacity, 0.15 L/min minimum operating flow, 24 VDC supply, 0.2 A rating, normally closed contact behavior, hydraulic oil type, connection dimensions, and physical condition. A nameplate photograph is particularly useful for older marine equipment.
Procurement Note
The is a relatively simple component, but it sits directly in a hydraulic control circuit. The important procurement risk is therefore not firmware compatibility; it is mechanical and functional mismatch.
Before approving a replacement, verify:
- Exact model: .
- Single-flow rather than double-flow configuration.
- Normally closed output.
- 24 VDC electrical circuit.
- 0.2 A rated current.
- 8–12 MPa hydraulic pressure range.
- 6 L/min rated flow capacity.
- 0.15 L/min minimum operating flow.
- HM32/HM46 hydraulic-oil compatibility.
- IP56 environmental requirement.
- Hydraulic connection and mounting dimensions.
- Actual flow direction in the installed piping.
For marine equipment, also compare the replacement against the original vessel documentation rather than relying only on a commercial part-number listing. Public documentation identifies as a Rongde single-flow switch, while some reseller listings provide additional identifiers such as MPN 42150803; those commercial identifiers should be treated as secondary until confirmed against the physical nameplate.
