When the boiler feedwater pump at a power plant is running, are you often troubled by the following issues? A loud “clanging” noise in the piping when the pump is stopped, valve leaks; drastic fluctuations in water level, causing the safety valves to trip repeatedly; or even attempting to use variable-frequency drives for speed control, only to find that the pump trips unexpectedly for no apparent reason...

The root cause of these issues often lies in the failure of the power transmission system to effectively mitigate the impact caused by high-pressure start-ups and shutdowns, as well as to adequately avoid the risk of cavitation. This article will focus on boiler feedwater pumps, analyzing the classic YOX560 torque-limiting hydraulic coupling solution, and introducing a superior product with even higher performance in the same class.

YOX560: The Time-Tested “Buffering Expert”
For boiler feed pumps with input speeds of 1,000 rpm or 1,500 rpm, the corresponding power transmission ranges are 40–80 kW and 120–270 kW, respectively. Under these operating conditions, the YOX560 limited-torque hydraulic coupling is a well-established, widely recognized, and extensively applied solution in the market.

Its core advantage lies in... Flexible transmission ：

Soft start, protects bearings With a starting overload factor of 1.5 to 1.8, it can smoothly build up torque and effectively absorb and balance the sudden axial thrust fluctuations generated during the start-up and shut-down of high-pressure pumps—much like adding an “air cushion” to the thrust bearing, thereby significantly extending its service life.

Mitigate water hammer and stabilize the system. By transmitting power through a liquid medium, the instantaneous release of kinetic energy in the medium when the pump stops can be significantly mitigated, thereby reducing pipeline vibrations and abnormal noises, and protecting valve and flange seals.

Overload protection, safe operation A overload factor of 2 to 2.5 during braking can provide isolation protection when the load suddenly increases, preventing the motor from stalling or the equipment from being damaged.

The YOX series boasts a comprehensive range of specifications and diverse structural designs, meeting the basic requirements for soft starting and overload protection in the vast majority of boiler feedwater pumps. It features high market transparency and is a reliable choice that has been proven through more than a decade of practical application.

Advanced Option: DXA560—Empowering Efficient and Stable Operation
As power plants increasingly demand long equipment operating cycles, maintenance-free operation, high reliability, and excellent speed-regulation compatibility, the DX series—a comprehensive upgrade based on the YOX series—has emerged.

Taking the DXA560 constant-torque hydraulic coupling of the same specification as an example, while inheriting all the fundamental advantages of the YOX560, it has achieved breakthroughs in key performance areas:

Ultra-long maintenance-free cycle The maintenance cycle has been extended from the conventional 6–12 months to 2–3 years, significantly reducing downtime maintenance costs and the frequency of manual interventions, making it particularly suitable for boiler feedwater pump operations that demand continuous and stable operation.

German high-elastic coupling technology It adopts a high-performance elastic coupling structure from Germany, replacing the traditional plum blossom elastic coupling. This design offers superior transmission performance, longer service life, and is easier to disassemble, install, and maintain, thereby improving on-site maintenance efficiency.

Standardized, High-Reliability Design The structure has been optimized and features a high degree of standardization, enabling superior overall stability and compatibility when handling the complex operating conditions of boiler feedwater pumps—for example, avoiding critical speeds and reducing response delays to improve water-level control.

In short, the DXA560 is built upon the reliable foundation of the YOX560 and designed specifically to meet the modern power plant’s core requirements for high reliability, low maintenance, and long service life. Enhanced upgraded version It is particularly well-suited for boiler feedwater pump applications that are heavily affected by water hammer, water level fluctuations, and variable-frequency interference, and where attention is paid to the overall lifecycle cost of equipment.

How to Choose: YOX560 vs. DXA560

If budget is the priority, operating conditions are relatively stable. Pursuing basic functionality and high cost performance, the classic and reliable YOX560 remains an ideal choice.

If you prioritize long-term operational efficiency and ultimate reliability. For applications characterized by high pressure, susceptibility to cavitation, frequent speed adjustments, or extremely low maintenance requirements, the higher-performance DXA560 will deliver lower failure risks, reduced downtime, and higher overall operational efficiency.

As an industry-leading enterprise, Guangdong Zhongxing Hydraulic fully understands the various demanding operating conditions of boiler feedwater pumps. We not only offer a comprehensive range of hydraulic transmission products but also leverage our extensive experience in power plant applications to provide you with expert selection advice and customized solutions, covering multiple dimensions such as energy efficiency assessment, material resistance to cavitation, and sealing reliability.