Key Management Points for ATOS Vane Pumps

Brand

ATOS/Italian Atos

Application Areas

Chemical, Petroleum, Road/Rail/Marine, Tobacco, General

ATOS Piston Pumps, ATOS Axial Piston Pumps, ATOS Vane Pumps, ATOS Hydraulic Cylinders

ATOS Vane Pump Working Principle

When the rotor of the ATOS vane pump rotates, the vanes, under the action of centrifugal force and pressurized oil, have their tips pressed tightly against the inner surface of the stator. Thus, the working volume formed by the two vanes, the rotor, and the inner surface of the stator first draws in oil from small to large, and then discharges oil from large to small. Two oil suction and discharge cycles are completed in one rotation of the vanes.

ATOS Vane Pump Working Principle

The ATOS vane pump consists of rotor 1, stator 2, vanes 3, a distribution plate, and end covers. The inner surface of the stator has cylindrical holes. There is an eccentricity between the rotor and the stator. The blades slide freely within the rotor slots. Under the centrifugal force of the rotating rotor and the pressure of the oil flowing through the blade roots, the blade tips adhere tightly to the inner surface of the stator, thus forming sealed working chambers between adjacent blades, the distribution plate, the stator, and the rotor. When the rotor rotates counterclockwise, the blades on the right side of the diagram extend outwards, gradually increasing the volume of the sealed working chambers and creating a vacuum. Oil is then drawn in through the suction port 6 and the window on the distribution plate 5. On the left side of the diagram, the blades retract inwards, gradually decreasing the volume of the sealed chambers. The oil in the sealed chambers is forced out through another window on the distribution plate and the pressure port 1, and discharged into the system. This type of pump performs one suction and one pressure cycle per rotor revolution, hence it is called a single-acting pump. The rotor is subjected to radial hydraulic imbalance forces, therefore it is also called an unbalanced pump, and its bearing load is relatively large. Changing the eccentricity between the stator and rotor changes the pump's displacement; therefore, this type of pump is a variable displacement pump.

The operating principle of the ATOS vane pump is similar to that of a single-acting vane pump, the only difference being that the stator surface consists of eight parts: two long-radius circular arcs, two short-radius circular arcs, and four transition curves. Furthermore, the stator and rotor are concentric. When the rotor rotates clockwise as shown in the diagram, the volume of the sealed working chamber gradually increases at the upper left and lower right corners (the suction zone), and gradually decreases at the lower left and upper right corners (the pressure zone). A sealing zone separates the suction and pressure zones. With each rotor revolution, each sealed working chamber completes two suction and two pressure actions, hence the name double-acting vane pump. The two suction zones and two pressure zones are radially symmetrical, and the hydraulic pressure acting on the rotor is radially balanced, thus it is also called a balanced vane pump.

The instantaneous flow rate of a double-acting vane pump is pulsating; the pulsation rate is small when the number of vanes is a multiple of 4. Therefore, the number of vanes in a double-acting vane pump is generally 12 or 16.

An ATOS vane pump is a pump in which vanes in the rotor slots contact the pump casing (stator rings), forcing the sucked liquid from the inlet side to the outlet side.

Key points for managing ATOS vane pumps:

Besides preventing dry running, overload, air intake, and excessive vacuum, the following should also be noted regarding ATOS vane pumps:

1. Changing the pump's rotation direction changes its suction and discharge directions. Vane pumps have a prescribed rotation direction and cannot be reversed. This is because the rotor vane slots are inclined, the vanes are chamfered, the vane bottoms communicate with the discharge chamber, and the throttling grooves and suction/discharge ports on the distribution plate are designed for the predetermined rotation direction. Reversible vane pumps must be specially designed.

2. Vane pump assembly: The distribution plate and stator must be correctly positioned using locating pins. The vanes, rotor, and distribution plate must not be installed backwards. The suction area on the inner surface of the stator is most prone to wear; if necessary, it can be flipped over for installation, so that the original suction area becomes the discharge area for continued use.

3. Disassembly and assembly: Keep the working surfaces clean, and ensure the oil is well filtered during operation. 4. Excessive clearance between the blades and the blade slots increases leakage; insufficient clearance prevents the blades from freely expanding and contracting, leading to malfunction.

5. The axial clearance of a vane pump significantly affects ηv.

1) Small pumps: 0.015～0.03mm

2) Medium pumps: 0.02～0.045mm

6. The temperature and viscosity of the oil should generally not exceed 55℃, and the viscosity should be between 17～37mm²/s. Too high a viscosity makes oil suction difficult; too low a viscosity leads to severe leakage.

ATOS vane pump stock list:

PFE-31016/1DT

PFE-31016/1DU

PFE-31022/1DT

PFE-31022/1DU

PFE-31022/1DW

PFE-31028/1DT

PFE-31028/1DU

PFE-31028/1DV

PFE-31036/1DT

PFE-31036/1DU 20

PFE-31036/1DV 20

PFE-31036/1DW

PFE-31044/1DT 20

PFE-31044/1DU 20

PFE-31044/1DV 20

PFE-32028/3DT 20

PFE-32028/3DV 20 PFE-32036/3DT

PFE-41037/1DU 20

PFE-41045/1DT

PFE-41045/1DU 20

Italian ATOS

Reasons and Troubleshooting Methods for Vane Pumps Failing to Suction Oil

Common Faults and Their Causes

Troubleshooting Methods

Low oil level, unable to draw oil

Check and add oil to the specified level

Excessive oil viscosity, causing the vanes to not slide smoothly in the rotor

Slots

Generally use 20# hydraulic oil or 22# turbine oil

Poor contact between the distributor plate end face and the inner plane of the casing, causing communication between the high and low pressure chambers

Repair the distributor plate end face

Sand holes inside the pump body, causing communication between the high and low pressure chambers

Replace

Motor rotation reversed

Correct