2019-07-01
1Introduction
High and low pressure thin oil stations (including high and low pressure two oil supply systems) can be used for static and dynamic pressure lubrication of pipe mill bearings (torths and slip rings) or main bearings (bearings and hollow shafts) in cement plants.
The high-pressure oil supply system forcibly inputs pressure oil to the oil chamber in the middle of the tow before the tube mill starts and stops, so that the slip ring (tube mill) floats to form a static pressure oil film of a certain thickness to avoid the rotation speed of the mill. In the case of too low, the tow and the slip ring are dryly rubbed due to the formation of the dynamic pressure oil film, and the service life of the tray is prolonged.
The high pressure pump stops working after the tube mill reaches normal speed or stops completely. The low-pressure oil supply system supplies oil to the sliding bearing before the start of the grinding machine. After the tube mill stops, it stops working for a while, and its function is to cool the sliding bearing and provide the lubrication required to generate the dynamic pressure oil film. oil.
Since the determination of parameters such as pressure and flow rate in the low pressure part is relatively simple, this paper only discusses some parameters of the high pressure part.
2Working principle of high pressure oil supply system
The high-pressure oil pump outputs oil, which is supplied to the tow oil chamber through the one-way valve. When the pressure in the oil chamber rises to reach “high pressure”, the sum of the forces on the slip ring is equal to the total weight (G) of the tube mill. The mill is jacked up, forming a gap between the tow and the slip ring, and the oil output from the oil pump overflows from the oil chamber to the periphery through the gap to form a static pressure oil film.
At this time, the oil pressure in the oil chamber also drops to a constant pressure (high and medium pressure), and gradually decreases from the oil chamber to the edge of the tow.
The pressure change during the formation of the hydrostatic oil film is shown in Fig.
2.When the system is overloaded, the safety valve opens to create an overflow to relieve pressure and protect the system. The set pressure of the safety valve should be higher than the "high pressure". The electrical contact pressure gauge measures the oil pressure entering the oil chamber (if the pipe resistance is not considered, it can be approximated as the oil pressure in the oil chamber), which is used to control the opening and closing of the tube mill system.We are erw tube mill manufacturer,you can know it.
Because one tube mill has a total of 4 tows, two tows at the inlet and outlet ends (Fig. 3). Therefore, the effective total load force of the oil pressure on the slip ring is:
G=4fcos30°=4Pacos30° (1)
Where f - the force of a single tow high pressure oil on the slip ring, N;
P--oil pressure, MPa;
A--the pressure area of a single tow, m2;
Before the tube mill is lifted, the bearing area of the tuva is equal to the area of the oil chamber, and the pressure across the working surface is equal. Once the tube mill is jacked up (ie, a hydrostatic oil film is formed), the pressure bearing area is extended to the entire tow, when the pressure in the oil chamber is equal, and the pressure in the oil chamber is gradually reduced until the edge of the tow is zero.
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