Abstract: This article introduces the background technology, main structure, technological innovation, system principles, and examples of the new electromechanical hydraulic integrated single acting actuator. The adoption of a new electromechanical hydraulic integrated single acting actuator in the project is an inevitable result of the gradual replacement of imported products by pump tank isolation control equipment.
Keywords: Electrohydraulic actuator; Single acting; Integration; Fire resistant hydraulic relief valve; Hydraulic integrated valve block; Spring;
0 Introduction
With the continuous development of petrochemical refining projects and the continuous improvement of industrial automation control level, the new type of mechatronics hydraulic integrated single acting actuator is an inevitable product of industrial automation development. At the same time, as a type of drive device for tank bottom shut-off valves, it has been vigorously promoted and applied.
It has been widely promoted and applied in the polypropylene raw material gas tank area and pump station, gas separation raw material and commodity liquefied gas tank area and pump station. The purpose of quickly cutting off the valve is achieved through hydraulic spring reset. Under normal production conditions, the new mechatronics hydraulic integrated actuator is required to work stably, operate smoothly, and have high reliability. In case of accidents (fire), the action should be sensitive, especially when the valve is quickly cut off to ensure the safety of the tank farm and pump station. In order to better demonstrate the successful application of the new electromechanical hydraulic integrated single acting actuator in the isolation of petrochemical pump tanks, the product composition and working principle are further elaborated.
1 Background Technology
The traditional single acting electro-hydraulic actuator has a complex structure (separated from the electrical control system and hydraulic control system), a large volume, and a compressed spring that is compressed for a long time can easily cause spring deformation and difficult to recover, resulting in a decrease in the reset ability of the spring and a decrease in the service life of the spring. It is also difficult for the actuator to quickly reset the valve, resulting in inadequate valve action.
If it is necessary to quickly reset the valve in an accident state, it is difficult to achieve traditional single acting electro-hydraulic actuators. The reason is that in order to achieve automatic reset, traditional electro-hydraulic actuators must be manually controlled (with power signal given), in order to ultimately achieve quick opening or closing of the valve. When in certain flammable, explosive, fire and other situations, especially in the petrochemical and natural gas fields, electronic control systems often malfunction due to fire and explosion sites, resulting in the inability of the electro-hydraulic actuator to quickly close the valve, ultimately exacerbating the occurrence of safety accidents.
In order to overcome the shortcomings of traditional single acting electro-hydraulic actuators and take into account the importance of the petrochemical polypropylene raw material gas tank area and pump station, gas separation raw material and commodity liquefied gas tank area and pump station pump tank, Lishui Zhongde Petrochemical Equipment Co., Ltd. has developed a new type of mechatronics hydraulic integrated single acting actuator with intrinsic safety fully automatic fire resistant hydraulic relief valve with fire protection function.
2. Main Structure and Principle
The new mechatronics hydraulic integrated single acting actuator adopts an integrated structure, which is composed of five parts: electronic control system, hydraulic integrated system, hydraulic manual operation mechanism, mechanical execution mechanism, and fireproof hydraulic relief valve. (See Figures 1 and 2)
This actuator adopts a plunger sealed nitrogen spring reset, which optimizes the product structure, ensures the normal reset of the valve, and reduces the risk of the actuator not opening and closing the valve in place quickly.
The electronic control system includes a controller and servo motor; The hydraulic system includes oil tank, hydraulic integrated valve block, gear pump, plug-in valve, oil circuit, etc; The hydraulic system is Tight junction with the servo motor in the electronic control system and the oil tank end cover; The mechanical actuator includes a hydraulic cylinder, piston, gear, and plunger sealed nitrogen spring. When the signal from the 1 control system is input to the electro-hydraulic actuator, the 2 motor rotates and drives the 3 gear pump. At this time, hydraulic oil passes through the 4 hydraulic manifold block, causing the oil pressure to increase and enter the 6 cylinder. The piston of the cylinder generates thrust under the action of the oil pressure, causing the 7 spring to compress. The actuator performs a 0 o to 90 o angle under the mechanical conversion of the gear and rack. When resetting is required, rely on the force of the 7 springs themselves and release the pressure of the 6 cylinder through the 4 hydraulic integrated valve block. Under the action of the 7 springs, push the piston and gear to rotate and perform a 90 o to 0 o angle reset. When a fire occurs on site, the hydraulic system of the actuator is equipped with 8 fire resistant hydraulic relief valves, which automatically open at the specified temperature to quickly release the oil pressure of the 6 cylinders. Under the action of the spring, the actuator can quickly close or open. When the actuator needs manual operation in the event of power outage, turn the 9 manual valve to the "open" position and close the 5 manual on-off valve. At this time, manually operate the manual pump to the position of 0-90 o. When resetting, open the 5 manual on-off valve to relieve the pressure of the 6 oil cylinder, and under the action of the 7 spring force, reset from 90 o to 0 o.
This new type of mechatronics hydraulic integrated single action actuator achieves rapid reset of the valve through the rebound of the plunger sealed nitrogen spring, increasing the output torque of the single action actuator spring, ensuring a large rebound force, and making the valve reset action fast, stable, and reliable.
3. Technological Innovation
Innovation point 1: Adopting plug-in valve hydraulic integration technology, the hydraulic components are integrated into one, replacing the stacking of traditional electro-hydraulic actuators and the installation of pipelines and plate structures, reducing leakage between hydraulic system components and pipelines.
Innovation point 2: By incorporating pressure and displacement (angle) sensors, adopting microcontroller control technology, integrating real-time data acquisition and networked system control modules with ModbusRtube standard communication interfaces, the control accuracy is improved, and the communication capability of the new electromechanical hydraulic integrated actuator is also enhanced.
Innovation point three: The high-precision gear pump is driven by a DC brushless motor coaxial, replacing the larger hydraulic servo valve in traditional hydraulic control systems, simplifying the structure and improving reliability.
Innovation point 4: Adopting a fire resistant hydraulic relief valve with intrinsic safety, replacing the traditional emergency signal control mainly based on electromagnetic valves, saving costs and enhancing safety.
4 Examples
When the environmental temperature at the scene of a fire reaches the specified dangerous temperature, it is required that the actuator must quickly close or open the valve. At this time, the fire-resistant hydraulic relief valve of the new mechatronics hydraulic integrated actuator will automatically open the oil inlet and return ports. And under the action of spring force, the hydraulic oil quickly passes through the fireproof hydraulic relief valve and returns to the oil tank for pressure relief, thus achieving the goal of the new electromechanical hydraulic integrated single action actuator to quickly close or open the valve without the need for control signals in emergency situations.
The successful operation of the new mechatronics hydraulic integrated single acting actuator in the isolation area of the Shijiazhuang refining pump tank plays a crucial role in safe and stable production and optimization of production operations.
5 Conclusion
From the above, it can be seen that the new mechatronics hydraulic integrated single acting actuator is an important control device for the isolation area of petroleum refining pump tanks, and has successfully achieved rapid automatic opening or closing of valves through technological innovation. After long-term on-site operation, the new electromechanical hydraulic integrated single acting actuator has been successfully applied.
