The precise control of the turbine speed control system depends on the efficient response capability of the actuator, and the performance of the fire-resistant oil filter element as the core purification component of the hydraulic system directly affects the oil quality and oil supply stability. There is a profound intrinsic relationship between the pressure drop characteristics of the HQ16.10Z EH oil actuator filter element and the system response delay. This relationship involves both the principles of fluid dynamics and is restricted by multiple factors such as material properties and oil state.

1. Formation mechanism of pressure drop: from filter element characteristics to system dynamic imbalance

The filter element HQ16.10Z pressure drop refers to the pressure loss caused by resistance when the oil flows through the filter material. For the high-pressure filter element HQ16.10Z, the causes of pressure drop can be attributed to two categories: structural pressure drop and dynamic contamination pressure drop.

Inherent influence of structural pressure drop

The design parameters of the filter element determine the initial pressure drop level. The actuator filter element HQ16.10Z adopts a multi-layer gradient fiber structure. While ensuring high filtration accuracy, it reduces the basic pressure drop by expanding the effective filtration area. However, when the system flow increases suddenly due to a sudden load change, even if the filter element is not blocked, the instantaneous increase in oil flow rate will still cause a nonlinear increase in pressure drop. This pressure drop fluctuation may interfere with the flow-pressure feedback balance of the servo valve, causing a temporary mismatch between the command signal and the execution action.

Cumulative effect of dynamic contamination pressure drop

The particles, colloids and hydrolysis products carried by the fire-resistant oil during the circulation process will gradually block the filter element pores. A case of a power plant shows that when the filter element pressure difference increases from the initial 0.3MPa to 1.2MPa, the actuator valve action delay is extended from 50ms to 220ms. This pressure drop accumulation not only weakens the oil supply pressure, but also forces the oil pump to increase the output power to compensate for the pressure loss, aggravating the system energy consumption and temperature rise, forming a vicious cycle.

2. Chain effect of pressure drop amplification response delay

The actuator response delay is a direct reflection of the sensitivity of the hydraulic control system, and the abnormal change of the filter element pressure drop can amplify the delay effect through the following paths:

Oil supply pressure attenuation and insufficient servo valve driving force

When the filter element pressure drop exceeds the design threshold, the actuator inlet pressure is significantly reduced. Taking a 300MW unit as an example, for every 0.5MPa increase in the pressure difference of the EH oil filter element HQ16.10Z, the servo valve driving oil pressure drops by about 8%, resulting in a 15%-20% reduction in the valve core movement speed. At this time, the actuator needs longer to complete the stroke positioning, especially in emergency conditions such as unit load rejection, and the delay may cause overshoot or oscillation risks.

Oil cavitation and flow pulsation interference

Under high pressure drop environment, local vacuum is easily generated when the oil flows through the narrow channel of the filter element, inducing cavitation. When the cavitation bubbles collapse in the high pressure area, shock waves are released, which aggravates pipeline vibration and generates high-frequency flow pulsation. This pulsation interferes with the steady-state control of the servo valve, which manifests as a “step-by-step” response of the command signal, further extending the system adjustment time.

Oil temperature increase and viscosity characteristic deterioration

The increase in pressure drop leads to increased friction loss in the system and faster oil temperature rise. The viscosity of the fire-resistant oil decreases with the increase in temperature, which increases the internal leakage of the servo valve and reduces the pressure-flow gain. The measured data of a chemical plant showed that when the oil temperature rose from 45℃ to 65℃, the full stroke response time of the actuator was extended by 30%, and the continuous high pressure drop of the filter element was one of the key causes of oil temperature out of control.

3. Systemic risk: from local failure to global out of control

The abnormal pressure drop of the filter element HQ16.10Z of the EH actuator not only causes response delay, but also threatens the system safety through the coupling effect of “pressure-contamination-temperature”:

Servo valve jamming and frequent replacement

The oil contamination accompanied by high pressure drop will accelerate the wear of the servo valve. The long-term excess pressure difference of the filter element will cause particles to be embedded in the valve core gap under the entrainment of high-pressure oil flow, forming mechanical jamming, and the delayed response action forces the operator to repeatedly adjust the command, aggravating the fatigue damage of the valve core. For expensive servo valves, it will be a high economic loss.

Decrease in control accuracy and unit oscillation

The delayed response of the actuator will destroy the dynamic balance between turbine power and steam parameters. In the heating condition of the 300MW unit, the abnormal pressure drop of the filter element caused the continuous swing of the steam extraction regulating valve, causing the heating pressure to fluctuate by ±0.7MPa, threatening the safety of downstream user equipment.

It can be seen that the pressure drop and response delay problem of the fire-resistant actuator filter element HQ16.10Z is essentially a game between the energy transfer efficiency and control accuracy of the hydraulic system. The engineering practice of the HQ16.10Z filter element shows that only by incorporating the pressure drop control into the global framework of the system dynamic characteristics analysis can the vicious cycle of “pressure drop increase-response delay-system degradation” be broken.

When looking for high-quality, reliable oil filters, YOYIK is undoubtedly a choice worth considering. The company specializes in providing a variety of power equipment including steam turbine accessories, and has won wide acclaim for its high-quality products and services. For more information or inquiries, please contact the customer service below:
E-mail: sales@yoyik.com
Tel: +86-838-2226655
Whatsapp: +86-13618105229

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