On a more environmentally friendly energy-efficient method of flushing the hydraulic system

Paper Keywords: pump the oil hydraulic flushing of the process control environment protection and energy
Abstract: Details of Baosteel Heavy Plate Sapporo 5000 mm hydraulic shearing line "of the pump the tank," the washing and construction process control, and with the traditional "pickling line" approach compared with the environmental protection and energy saving advantages.

0 Introduction
The author mainly 5000mm Heavy Plate Mill of Baosteel cut line hydraulic system "of the pump the tank," the washing and construction process control methods are introduced. By two characteristics of the hydraulic system flushing method compared to flush the hydraulic system to provide a more energy, more environmentally friendly washing methods.

1 "line pickling" and "pump the fuel tank of the" washing method and the advantages and disadvantages compared
"Online pickling" is a traditional hydraulic system flushing methods. Purpose is to remove rust and iron oxide pipeline skin. Is the hydraulic pipe installed, not removed, but the hydraulic piping and pickling equipment to form a rinse loop to loop pickling, rust, in addition to iron oxide skin, the oil was washed with washing, "remove" foreign bodies in the pipeline, water and residual acid, the working oil and then rinse. technology is relatively mature, the disadvantage is greater pollution of the environment, requires a lot of wash oil, washing costs, and it is difficult to pipe the water and residual acid discharge clean, which will lead to faster oxidation rate of hydraulic oil and hydraulic oil film thinning, component wear increased, and finally to the hydraulic system failure.

Baosteel Heavy Plate Mill 5000mm cutting line hydraulic system, to take the "pump the fuel tank" in the new irrigation methods. Purpose is to remove rust and iron oxide pipeline skin; to avoid the construction process produces iron oxide skin, to minimize the oil in the moisture content. method is to first "material management" for pickling, rust, its two ends sealed with plastic sheeting to prevent further rusting, pipe welding, always pass in the end of the pipe with a certain hydrogen pressure, until Welding is completed and when to break the hydrogen at room temperature to avoid oxide skin. drawback is that application of the washing process in the country much, the advantage of saving a lot of hydraulic flushing oil, greatly improved the construction environment, reducing environmental pollution, hydraulic system to get a good flushing effect, shorten the construction period, reduce the cost of washing.

2 heavy plate mill of Baosteel 5000 mm hydraulic cutting line
Baosteel Heavy Plate Mill 5000mm Cut Line hydraulic system includes three hydraulic systems are used, "the pump of the tank," the washing method, washing the precision needed to NAS6 level qualified.

Shear Hydraulic Shear system mainly to provide hydraulic power ontology, the system for the electro-hydraulic proportional valve control, system control pressure P 14 MPa, the hydraulic system pump station located in the MR08. Bilateral scissors and cut the hydraulic system partition Bilateral cut and split the main body scissors, for cutting edge devices and magnetic bilateral provide hydraulic power for the device, the system for the electro-hydraulic proportional valve and servo valve control, system control pressure P 14 MPa, the system pump station located in MR09 hydraulic station.

The main hydraulic system length cut body and the magnetic shear length of the device to provide hydraulic power, the system is electro-hydraulic proportional valve control. The system P pipe pressure 14MPa, the system hydraulic pumping station located in the MR10.

3 "pump the fuel tank of the" flushing of the hydraulic system of pipeline construction process control
To ensure that the hydraulic pump of the fuel tank pipe flush with the smooth progress of the need to strengthen the hydraulic equipment and pipeline installation process control, mainly to ensure that equipment, the cleanliness of the pipeline. According to the pipe material and supply channels to take different installation methods.

3.1 Foreign suppliers of carbon steel pipes and stainless steel pipes, wall very clean and has a dedicated cap, no pickling, can be constructed.

3.1.1 During the construction process, cutting or welding on pipes, the pipes on both sides of the nozzle to open, immediately after completion of dressing well.

3.1. 2 pipe cutting by mechanical cutting methods, can be used for large diameter stainless steel tube, plasma cutting, cutting is completed must be slag, oxide, iron and other flash clean up glitches.

3. 1.3 using ammonia pipe welding, welding pipe in the wall must be continuous charge ammonia, hydrogen filling pipe when soldering to ensure the air inside the pipe before the first full replacement into high purity hydrogen, and then welding, After welding and weld in the pipe after cooling to stop inflation, to ensure that pipe wall is not oxidized. welded immediately after the close the nozzle dressing, mainly to prevent moist air into the pipeline to accelerate oxidation, to ensure that the pipeline hydrogen pressure and purity, to improve the cleanliness of the pipeline and delay the pipe wall oxidation.

3.2 for the domestic supply pipeline in the acid plant for pickling, passivation, anti-rust oil spray treatment, qualified and then transported to the site for construction, construction techniques, the same channels with the overseas supplier. With particular attention to links is reasonable, accurate control of pickling the progress and number of tubes shipped to the site to prevent pipe corrosion oxidation, in order to guarantee the progress of the construction site, not the backlog shall prevail.

4 pump, the hydraulic system oil tank washing
4.1 Preparation before washing
4. 1.1 pipe installation is complete, the system plans to carefully check the confirmation only after the temporary pipeline connecting operation, all making Road to take over the temporary short-pickling and injection must be protective, temporary pipe connection is completed after the first group of pure nitrogen purged bottle, wrap the white wooden slats, then cast a binder (such as paste, white paint), on the export pipeline has been purged, within 5 min visual inspection of wood no debris on the white board, is qualified.

4.1. 2 in the production of the temporary connecting pipe, we must also clean up the tank, in particular: the dough with white flour and dust cleaning the tank, until the dough is white and no new impurities prevail. After a good cleaning the tank, response to addition of the oil tank for laboratory analysis, such as to achieve the precision required to raise to the tank, crude oil washing is generally not less than NAS10-level accuracy is satisfactory. filling with oil filter car oil from the hydraulic station for tank Note, filling the tank 3 / 4 position.

4.1. 3 Replace the oil filter is a key node in washing, will return to the oil filter 20u, filter replaced 3 u temporary filters, the high pressure oil filter back on the road to replace the temporary filter in the pressure , so washing after conclusion of the high pressure oil back on the road into a formal filter cartridge replacement, and return the temporary filter oil filter test would then be linked to the system formally replace the filter. the stage valve system proportional valves, servo valves replaced wash board.

4.1. 4 Rinse should be recognized before the oil pipeline has shut down the system focus and concentration of total oil pipeline oil discharge valve is closed.

4.2 the process of flushing the hydraulic system
4.2. 1 Hydraulic system flushing process (Figure 1)


4.2. 2 Taking into account the progress of the installation of mechanical and system size, flushing the entire system is generally divided into two steps. First pump station to the various valves connected into circuit in charge of road to wash; second step is and all After washing in charge of road, and then the hydraulic valve units to the various execution units connected into a loop of pipe flushing, washing according to the pipe diameter, loop length, cleanliness, etc. segments, segment rinse. Links to free papers Download Center http://www.hi138.com 4.2.3 rinse before starting the circulating pump on the oil tank for heating and filtration cycles, oil temperature increased to 40 for a 60 ��, started the hydraulic high-pressure pump, start flushing flows should be assessed after the charge of flushing flow rate is greater than 6m / s. Also check the fuel tank accessories are working properly, such as air filter is blocked, the high and low level alarm level and the circulation pump, high pressure pump of the chain is good, high-temperature alarm and temperature control device circulation pump, high pressure pump chain is good; the water cooler is already able to work properly.

4.2. 4 Rinse the whole system when the pressure is 4 a 6MPa, shear line hydraulic system pressure piston pumps are constant variables. First full release of electromagnetic relief valve on the main pump pressure regulator screws, with the point confirmed in moving the direction of motor rotation is correct, adjust the system pressure gauge to the electromagnetic relief valve setting the relief valve, relief valve lock, then adjust the pump to flush the system pressure gauge to the system 4 ~ 6 MPa, locked pump electro-hydraulic valve adjustment at this time, have power washing, pressure loss of power system security. To meet the irrigation flow rate of greater than 6m / s, while opening several pressures need to pump water.

4.3 points to note when flushing
4. 3.1 to have someone responsible for the washing operation, washing operation should be continuous, requiring the construction personnel records must be washed well, if abnormal, should stop the pump handle. Using online contamination detector test the cleanliness of each branch circuit and flow, when that flow can not meet the washing requirements of the other branch by closing the valve, or increased focus on pressure washing pump about the number of ways to meet the traffic requirements. rinse flow rate, flow and diameter were shown in Table 1:

4. 3.2 Detection of the filter at any time before and after the differential pressure, pressure that exceeds the value of the filter plug, clean or replace the filter .4.3.3 can be specifically responsible for sampling, sampling methods and procedures must be in accordance with relevant provisions of carried out a washing 4h after the start of 2 can be sampled once, after the decision in accordance with the results of sampling, the sampling interval and then decide. oil cleanliness inspection can use the foreign line contamination detector on line. on the high pressure pump outlet, the farthest side valve units, back to the line before the filter pressure joints at three sites tested. to all qualified for the three parts of washing compliance standards.

4. 3.4 oil temperature increased to 40 for a 60 ��, two main effects: first, reduce the degree of oil Bo is easy to generate turbulence in the pipeline flushing; the second is thermal expansion and contraction due to temperature to produce pipe, so that attached to the pipe wall of the welding slag, oxide and other loss. turbulent flushing the pipeline has more important effect of the impact to determine whether the turbulence, according to the fluid to determine the critical Reynolds number, when the flow of liquid Reynolds number is lower than critical Reynolds number, the current state of laminar flow, whereas turbulent flow of the liquid state. smooth metal circular pipes the critical Reynolds number from 2000 to 2300, the Reynolds number is calculated as:
Re = vd / y
Where the Reynolds number Re-
v-average velocity of the fluid pipe
d-to pipe diameter
Bo y-degree of movement of the liquid
When vd is constant, lower degree of movement Bo y, the Reynolds number will increase, so that turbulent flow of the liquid state to state.

5 Summary
5.1 pump, flush the tank and the applicable conditions of the characteristics of
5.1.1 Pressure from the use of formal power flushing pump as the oil pressure pump is the main provider of high-pressure medium, but the flow is relatively small and difficult to produce turbulence.

5.1. 2 hydraulic pressure pipe diameter pipeline relative to the return line of the diameter is relatively small, you need to install the temporary return pipe on the way regulation valve, to ensure the flushing loop pressure and flow.

5.2. 3 utilizes the pump, the fuel tank of the flushing method, the construction of pipelines and process equipment required is relatively high, to ensure pipeline wall is very clean.

5.2. 4 n a long construction period, relatively large hydraulic systems.

5.3 pump, the advantages of the tank washing
5. 3.1 shorten the cycle from construction to commissioning, saving construction time and commissioning hydraulic system, thereby reducing construction costs.

5. 3.2 significantly reduced the secondary acid substances and oil pollution, an official of the hydraulic oil used directly for flushing, after washing, do not need to replace the oil, in terms of energy saving and environmental protection, has a wider application value.

5.3. 3 and loop-line method of acid washing of oil, a decrease of the acid, and in other processes, no special circulation pump acid pump and oil flushing, reducing construction costs. Links to free Download Center http://www.hi138.com paper