Views: 0 Author: Site Editor Publish Time: 2026-03-11 Origin: Site
In the fields of hydraulic machinery, rotary tables of machining centers, construction machinery, wind power generation, etc., high-pressure multi-path rotary joints play a crucial role. They need to simultaneously transmit multiple high-pressure media - hydraulic oil to drive the actuators, coolant to remove heat, and compressed air for control - while ensuring no leakage. If the selection is incorrect, it can lead to equipment downtime at the very least, and in severe cases, it can even cause safety accidents.
I. Overview of High-Pressure Multi-Path Rotary Joint
The high-pressure multi-path rotary joint is a rotary sealing device capable of simultaneously transmitting two or more types of high-pressure media. It integrates multiple independent fluid circuits within a compact housing through a precisely designed internal channel structure.
From the perspective of pressure levels, "high pressure" generally refers to a working pressure of 25 MPa or above. Some ultra-high pressure products can reach 50 - 138 MPa. In terms of the number of channels, common specifications range from 2 to 12 channels. The more channels there are, the more complex the internal structure becomes, and the higher the manufacturing precision requirements are.
High-pressure multi-path rotary joints are widely used in processing centers' rotating worktables, hydraulic excavators, cranes, wind power generating units, metallurgical winding machines, and petroleum drilling equipment, etc.
II. Preparations Before Selecting the Model
Before choosing a high-pressure multi-channel rotary joint, you must first clearly define the three core operating parameters of the equipment. These parameters form the basis for the selection and are also an essential part of the communication with the supplier.
1.Maximum working pressure
This is the most crucial parameter. It is necessary to clearly define the normal working pressure of the equipment and the instantaneous maximum pressure when it is turned on. Different pressure levels correspond to different sealing structures and material configurations.
2. Maximum Rotational Speed
The rotational speed of the roller or shaft directly affects the selection of the joint structure. There is a mutually exclusive relationship between rotational speed and pressure - the higher the rotational speed, the lower the allowable working pressure.
3. Medium Type and Temperature
It is necessary to clearly define the type of medium (hydraulic oil, water, air, etc.) transmitted by each channel and its operating temperature range. Different media have completely different requirements for sealing materials.
III. Key Points for Selecting High-Pressure Multi-Path Rotary Connectors
Point 1: Design the product structure based on the matching of pressure and speed.
Pressure and speed are the two most crucial parameters in the selection process, and they are mutually restrictive - the indicated technical parameters are the maximum values and cannot be used simultaneously.
According to the working conditions, the high-pressure multi-path rotary joints are mainly divided into two categories:
Low-speed high-pressure type rotary joints: Suitable for working conditions with a rotational speed of 10 RPM or less and a pressure of up to 30 MPa. It is supported by two large and precise bearings, and these bearings require no maintenance throughout their lifespan. This type is suitable for low-speed heavy-load equipment such as hydraulic workstations, coiling machines, and large bag rotary tables.
High-speed and high-pressure type rotary joints: Suitable for working conditions with rotational speed up to 3000 RPM and pressure up to 25 MPa. It adopts a special clearance sealing structure, without contact wear of the sealing ring. The rotational torque is small and not affected by pressure and temperature. It is suitable for hydraulic equipment with high-speed rotation.
Point 2: Determine the number of channels and the combination of media
The number of channels is usually determined based on functional requirements. Common specifications include 2, 3, 4, 6, 8, and even 12 channels. After counting the types and quantities of media that the equipment needs to transmit simultaneously, inform the manufacturer of the specific media for each channel.
Key point to note: The greatest technical challenge of high-pressure multi-channel rotary joints lies in the isolation of the channels from each other. It is strictly prohibited to arrange two media that may have dangerous reactions or cross-contamination and thereby affect product quality in adjacent channels. For example, hydraulic oil and water-based media should be arranged separately, or redundant seals should be added.
In addition, it is necessary to consider whether a central through-hole is required for threading wires, signal lines, and other cables.
Point 3: Confirm the interface size and connection type
Based on the pipeline configuration and space constraints, determine the interface parameters:
Bore: Select the bore size of the rotary joint based on the flow rate of the required input and output media.
Connection method: Flange connection or threaded connection? Rotating type or fixed type for the inner pipe?
Thread direction: When using threaded connections, it is necessary to clearly determine the rotation direction of the equipment - the thread direction should be opposite to the rotation direction of the equipment (or the same, depending on the specific structure) to prevent loosening during operation.
Thread standard: Confirm the specification standards of the interface threads (such as G threads, NPT threads, metric threads)
Point 4: Pay attention to the sealing structure and materials
The sealing element is the "heart" of the rotary joint. Its structure and materials directly determine the service life and reliability of the joint.
Sealing structure: High-quality high-pressure rotary joints usually adopt a balanced sealing structure, ensuring that the pressure generated at both ends of the sealing ring is nearly equal. This effectively reduces the wear of the sealing surface caused by the sealing load. Some products adopt a clearance sealing structure, without any contact wear of the sealing ring, and are suitable for high-speed operating conditions.
Sealing materials: Under high-pressure conditions, specialized sealing components are typically used, such as brands like Parker and Dichtomatik. The appropriate sealing material should be selected based on the medium temperature. For normal temperatures ≤ 120℃, materials resistant to high temperatures like fluororubber should be chosen for high-temperature applications.
Product grade: Different product grades correspond to different service lifetimes - the general grade has a maximum rotational speed of 100 RPM, with a working lifetime of approximately 6 million rotations; the industrial grade can reach 300 RPM, with a working lifetime of 20 million rotations, and uses dedicated sealing components.
IV.Select a professional and reliable supplier
Shandong Focus Machinery Co., Ltd. is a high-tech enterprise specializing in the research and development of rotary joints. It fully understands the significance of stable equipment operation for customers.
Unlike traditional trade, we offer 'one-on-one' in-depth services by experienced engineers, ranging from condition analysis to selection and design, to ensure that each joint perfectly meets the requirements of your production line. We strictly control the quality of materials from the source and implement meticulous quality control, with a one-year worry-free warranty as the bottom line. We are committed to becoming your long-term strategic partner. We believe that the high stability and durability of Focus Machinery Co., Ltd.'s products will serve as a solid backing for the long-term efficient operation of your production line, bringing you continuous benefits and returns.
High-pressure multi-path rotary joints are the core components of high-end equipment for fluid systems. The selection of these components requires comprehensive consideration of multiple factors such as pressure, rotational speed, number of channels, medium type, temperature, and interface form. Choosing the right product ensures reliable operation of the equipment; selecting the wrong product may expose the equipment to risks of leakage, contamination, and even safety accidents.
Shandong Focus Machinery Co., Ltd. defines quality through strict material selection and quality control. Beyond the one-year warranty, it also promises stable protection throughout the entire lifecycle. Choosing Shandong Focus Machinery Co., Ltd. means choosing a mutually beneficial future of long-term value and outstanding performance.
