Performance parameters of vane pump
The main performance of vane pump includes pressure, displacement, speed, efficiency and service life. The main structural parameters include long and short radius of stator slide surface (double acting vane pump)
(1) The working pressure of pressure single acting variable vane pump generally does not exceed 17.5MPa. The maximum working pressure of double acting vane pump has reached 28 ～ 30MPa, which is slightly lower than that of gear pump. The working pressure of cam rotor vane pump can reach 21MPa.
(2) The displacement estimation and range of vane pump mainly depend on the width of stator and rotor, inner diameter and eccentricity of stator (single acting vane pump), long and short radius of stator slide surface (double acting vane pump), number of blades, thickness and inclination angle of blades, etc. The approximate calculation formula of vane pump displacement is shown in the table below.
Approximate calculation formula of vane pump displacement
| type | computing model | Approximate calculation formula for displacement (mL/r) | illustrate |
| Single action |  | V=2πeBD×10-3 | E – stator eccentricity, mm; B – Width of stator and rotor, mm; D-Inner diameter of stator ring, mm |
| Double action |  | V=2B[π(R2-r2)-(R-r)/cosθ-bZ] ×10-3 | B – Width of stator and rotor, mm; R/r – The long and short radii of the stator slide surface, mm; θ- Blade inclination angle; B – blade width, mm; Z – Number of blades |
It is known that the displacement range of common variable vane pump is 6 ~ 120ml / R. The displacement range of double acting vane pump is 0.5 ~ 4200ml / R, but the common displacement is 2.5 ~ 300ml / R.
(3) The maximum speed of single acting variable displacement pump is about 3000r / min, and the minimum speed is limited (generally 600-900r / min) to ensure that there is enough centrifugal force to throw out the blade reliably. The maximum speed of small displacement double acting quantitative vane pump is 8000 ~ 10000r / min, but the general product is only 1500 ~ 2000r / min, which is generally lower than that of gear pump.
(4) The volumetric efficiency of single acting vane pump can reach 92% under rated condition, and that of double acting vane pump can exceed 94% under rated condition, which is slightly lower than that of gear pump, but the mechanical efficiency of vane pump is generally higher. So the total efficiency of the two is almost the same. Figure x shows the efficiency curve of a double acting vane pump.
(5) The service life of high-pressure vane pump is generally longer than that of gear pump, which can reach more than 5000h due to small bearing load and balanced force on valve plate.
(6) The noise of single acting variable vane pump is higher than that of variable piston pump. The noise of double acting vane pump is very low, which is equivalent to that of internal gear pump.
(7) The power density of the double acting vane pump is larger than that of the gear pump because of its larger working volume (“double acting” feature). However, the latter has higher allowable pressure and speed, and the outer gear pump uses aluminum alloy shell, so the gear pump still has the advantage in power density.
(8) For double acting vane pump, the ratio of large radius to small radius of stator slide surface is generally R / r = 1.06 ~ 1.15. Increasing the width b of rotor and stator can reduce the proportion of leakage along the end face to the total output flow, which is beneficial to improve the volumetric efficiency. However, when the value B is too large, the flow velocity in the distribution window will be too high, and the pressure loss will increase. For single acting pump, the bearing force will deteriorate, generally B / r = 0.45 ~ 1. For example, Yb series vane pump with flow rate of 25-200l / min B = 20-40mm. The eccentricity of single acting pump is generally E / d=
0.025～0.03。
The minimum number of blades (even number should be taken) Zmin = 6, considering the rotor strength, it is better to have fewer blades. However, in order to reduce the flow pulsation, the value of Z must match the shape of transition section in the stator slideway surface, generally 2 = 8 ~ 18, and z = 10 and 12 are the most. In order to reduce the flow pulsation, the blade number of single acting pump should be odd (z = 9 ~ 21).
The blade thickness should be as thin as possible on the premise of meeting the strength requirements and process possibility, generally B = 1.8 ~ 2.5mm. For example, the thickness of Yb series vane pump with flow rate of 12-200l / min is b = 2.25mm.
The caster angle of single acting pump is generally 0 ° to 24 °. The blade rake angle of double acting pump is usually 0 ° to 14 °. For example, the blade rake angle of Yb series vane pump with a flow rate of 10-100 L / min is θ – 13 °.
