Structure and working principle of Italian ATOS gear pump

Brand

ATOS/Italian Atos

ATOS gear pumps are a type of positive displacement pump, consisting of two gears, a pump body, and front and rear covers forming two enclosed spaces. When the gears rotate, the volume of the space on the disengaged side increases, creating a vacuum that draws in liquid. Conversely, the volume of the space on the meshing side decreases, forcing the liquid into the pipeline. The suction and discharge chambers are separated by the meshing line of the two gears. The pressure at the discharge port of the gear pump depends entirely on the resistance at the pump outlet.

ATOS Gear Pump Structure and Principle:

The structure of the ATOS gear pump is very simple. Its most basic form consists of two identical gears meshing and rotating within a tightly fitted housing. The interior of this housing is shaped like an "8," housing the two gears. The outer diameter and sides of the gears fit tightly into the housing. Material from the extruder enters between the two gears at the suction inlet, filling this space. As the gears rotate, the material moves along the housing and is finally discharged when the two gears mesh. In technical terms, a gear pump, also called a positive displacement device, works like a piston in a cylinder. As one gear engages with the fluid space of another, the liquid is mechanically forced out. Because liquid is incompressible, the liquid and the gear cannot occupy the same space simultaneously, thus expelling the liquid. This phenomenon occurs continuously due to the constant meshing of the gears, providing a continuous discharge rate at the pump outlet; the discharge rate is the same per revolution. With the continuous rotation of the drive shaft, the pump continuously discharges fluid. The pump's flow rate is directly related to its rotational speed. In reality, there is a small amount of fluid loss within the pump, preventing it from reaching 100% efficiency. This is because the fluid is used to lubricate the bearings and gears, and the pump body cannot be perfectly flush, so a small amount of fluid loss is inevitable. However, the pump can still operate well, achieving 93%–98% efficiency for most extruded materials. For fluids whose viscosity or density varies during the process, this type of pump is not significantly affected. If a damper is present, such as a filter or restrictor on the outlet side, the pump will force fluid through them. If this damper changes during operation—that is, if the filter becomes dirty or clogged, or the back pressure of the restrictor increases—the pump will still maintain a constant flow rate until the mechanical limit of the weakest component in the unit is reached (usually equipped with a torque limiter).

ATOS gear pumps are driven by an independent motor, effectively blocking upstream pressure pulsations and flow fluctuations. Pressure pulsations at the gear pump outlet can be controlled to within 1%. Using a gear pump on an extrusion line can increase flow output speed, reduce material shearing and residence time in the extruder, and reduce extrusion temperature and pressure pulsations, thereby improving productivity and product quality.

ATOS Gear Pump Installation Considerations:

When installing a gear pump, pay attention to the following:

1. Conduct a detailed inspection of all components; all should meet the relevant standards.

2. The perpendicularity of the gear end faces to the shaft centerline and the parallelism of the gear end faces should be qualified; the gear meshing should be good.

3. The shaft diameter should meet the technical requirements, and the coaxiality of the bushing or bearing with the shaft diameter should be qualified.

4. The gear end face clearance should be adjusted appropriately.

5. When tightening the end face bolts, the force should be symmetrical and even; rotate the rotor while tightening. If jamming occurs, loosen the bolts and retighten.

6. When adding packing and tightening the pressure cover, rotate the rotor while tightening; do not tighten too tightly.

ATOS

Usage Precautions:

ATOS

When using a gear pump, the following precautions should be taken:

(l) The pump drive shaft and the prime mover output shaft should be installed using a flexible coupling, with a coaxiality deviation of less than 0.1mm. For bushing couplings, the coaxiality deviation should be less than 0.05mm.

(2) The transmission device should ensure that the pump's drive shaft is under stress within the allowable range.

(3) The pump's suction height should not exceed 0.5m.

(4) A mesh filter should be installed at the pump's suction port, with a filter accuracy of less than 40μm. The filter installed on the system's return oil line should ideally have a precision of 20μm or less.

(5) The working oil should be selected strictly according to regulations, with a working temperature range of -20 to 80℃.

(6) The pump's rotation direction must be correct, meaning the pump's inlet and outlet positions must be correct. Disassembly and assembly of the pump must be strictly performed according to the manufacturer's instruction manual.

(7) Tighten the screws on the pump's inlet and outlet pipe joints. The sealing devices must be reliable to prevent cavitation and oil leakage, which would affect the pump's performance. Avoid starting the pump under load and stopping it under load.

(8) Before starting, check that the system's relief valve (safety valve) is at the set permissible pressure.

(9) For new pumps or repaired hydraulic pumps, perform no-load operation and a short period of overload operation before operation. Then check the pump's working condition; leaks, impact sounds, excessive heat, and excessive noise are not allowed. (l0) If the pump is not used for a long time, it should be disconnected from the prime mover. When using it again, do not immediately use the maximum load; it should be run under no-load for at least 10 minutes.

PFG-174

PFG-187

PFG-199

PFG-211

PFG-214

PFG-216

PFG-218

PFG-221

PFG-327

PFG-340

PFG-354

PFG-210

PFG-114/D

PFG-120/D

PFG-128/D

PFG-142/D

PFG-160/D

PFG-174/D

PFG-187/D

PFG-199/D

PFG-210/D

PFG-211/D

The company mainly deals with European and American brands and can source brands from any European country. For example, our key German brands include: BURKERT, DEMAG, HAWE, REXROTH, HYDAC, PILZ relays, FESTO, IFM sensors, E+H, HEIDENHAIN, P+F sensors, SICK, TURCK, and HIRSCHMANN industrial switches. German brands: Hengstler, Murr, Schmersal, Samson, EPRO (Emerson Group)

American brands: MOOG, ASCO, MAC, NUMATICS, PARKER, VICKERS, ROSS

British brands: Norgren

Italian brands: OMAL, ATOS, CAMOZZI, UNIVER, Camozzi