Armenia Intellectual Property Agency
Utility Model Number: 130 U
Date of Patent: June 15, 2007
Inventor: Varuzhan Harutyunyan, Nor-Nork 9th massive 97/7, 0059 Yerevan, Armenia
Application No.: AM20070004U
Filed: January 16, 2007
The utility model represents as a rotary pump. The pump is expected to use for delivering viscous liquids. It can be used for delivering fuels, lubricants and can have an application in hydraulic machines as actuator and motor.
The prototype is well-known gear pump, which has housing and two interlocked gears. There is a small clearance between the gears and the internal surfaces of the housing. The housing has inlet and outlet holes. The motor transfers the rolling motion to one gear directly and to other one through gear connection. Teeth intake the liquid into the cavities formed by them from the inlet hole and deliver it to the outlet hole along the profile surface of the housing. The liquid can not flow in the opposite direction, because the teeth are interlocked between the suction and pressure zones.
The pump has the following weaknesses:
1. Because the suction occurs at the expense of the cavity formed by two neighbor teeth, the pump has lower volumetric efficiency, which limits the liquid velocity up to 6-8 meter/second and the capacity accordingly.
2. The absolute pressure in the suction zone must be higher than the centrifugal pressure of the liquid in order the liquid to flow into the cavities between teeth, which makes a barrier for reducing overall dimensions of the pump. Besides, it limits the pump capacity too.
3. Because teeth are sliding during the action, and because they are acting with higher forces against each other, the pump has lower efficiency.
The task of the utility model is the following:
Improve the structure of the pump so, that it can generate higher capacity and efficiency at the same time.The External Two Teeth Gear Pump has housing and two interlocked gears too, which are in pin connection with the housing, but the pump differs from the gear pump in the following way:Here, one of the gears represents as two teeth rotor and the other one as two cavity rotor. They are rigidly attached with additional interlocked pinions. During the pump operation the two teeth rotor’s involute teeth and the two cavity rotor’s involute cavities are interlocking or the cylindrical profiles revolve on each other.The nature of the utility model is illustrated using two figures, where in figure 1 the pump is shown in 3D view and in figure 2 in top view.The pump has two teeth rotor (1), two cavity rotor (2), which are in pin connection with housing (3) through shafts (4 and 5). These shafts are rigidly joint to interlocked pinions (6 and 7). The housing has inlet (8) and outlet (9) holes. The profile of the tooth (10) and the profile of the cavity (11) correspondingly represent as profile of the point of tooth and the profile of dedendum of the involute gear, considering the cylindrical contours of the rotors (12 and 13) as the pitch circles of that involute profiles. The diameters of these pitch circles are equal. The pinions (6 and 7) have the same pitch circle diameter too. The pitches of the teeth and the cavities are equal (t) in order to provide smooth meshing.The pump operates in the following way:
The motor rotates the two teeth rotor (1) through the shaft (4). At the same time, the two cavity rotor (2) takes the rolling motion too through the shafts (4 and 5) and the pinions (6 and 7). The two teeth rotor (1) and the two cavity rotor (2) roll on each other through the cylindrical profiles (12 and 13) or mesh through involute profiles (10 and 11). When the rotors rotate in the shown direction, the liquid is drawn through the inlet hole (8) into the increasing volume enclosed by the tooth profile, the rotors' cylindrical surfaces and the internal surfaces of the housing until the next tooth contact with corresponding cavity. Then the enclosed liquid between two teeth rotates without changing its volume till the previous tooth contact with its cavity. After that, the liquid is discharged through the outlet hole (9), because the liquid enclosing volume starts to decrease. The involute and cylindrical contacts eliminate the liquid flow in the opposite direction, i.e. from the outlet hole into the inlet hole.
Because the pump’s suction volume is much higher than the gear pump’s suction volume, the External Two Teeth Gear Pump enables to increase RPM and consequently the pump capacity too. Besides the friction forces between the rotors and the pinions are very small, because the two cavity rotor performs no-load operation and as a result insignificant forces exist between the rotors and the pinions. That is why the pump has higher efficiency too.
The External Two Teeth Lobe Pump has housing (3) and two interlocked gears, which are in pin connection with the housing.
In addition, one of the gears represents as two teeth rotor (1) having two opposed teeth (10) and the other one as two cavity rotor (2) having two opposed cavities (11); the two teeth rotor’s involute teeth and the two cavity rotor’s involute cavities are interlocking or their cylindrical profiles (12 and 13) revolve on each other, the diameters of the cylindrical profiles of two teeth rotor and two cavity rotor are equal, these profiles represent as pitch circles for the involute profiles of the two teeth rotor's teeth and the two cavity rotor's cavities, the rotors are rigidly joint with additional meshed pinions (6 and 7), which have the same pitch circle diameter .