JPH0255633B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a compound pump in which a booster pump is provided upstream of a main pump to increase the suction capacity. This invention relates to a lightweight and compact compound pump that has significantly increased suction capacity by adopting

[Conventional technology]

In general, gear pumps and vane pumps are positive displacement pumps, so they have self-priming performance, good suction performance, simple structure, high discharge pressure, and small size. For this reason, gear pumps are often used as accessories to mechanical equipment in places with limited space, and there is a strong demand for further downsizing. Furthermore,
Due to limited space, they were often installed in locations with poor suction conditions, such as on top of tanks.

In addition, as part of miniaturization efforts are being made to increase speed, but when rotating at high speeds, the limits of suction performance of gear pumps and vane pumps become a problem. Furthermore, as the types of liquids handled are becoming wider and the temperature of the liquid is higher, the vapor pressure of the liquid becomes higher, which also poses a suction limit problem.

Traditionally, these gear pumps and vane pumps
Since the suction performance is already good, there are few cases where a booster pump is attached to further improve the suction performance, but in known examples, the booster pump is an axial flow pump that increases pressure in the axial direction, a mixed flow pump, and a gear pump. The one installed in the front row was hot.

FIG. 3 shows a conventional example, in which the drive shaft 1
The drive gear 2 attached to the rear casing of the gear pump A and the driven gear 4 supported by the driven shaft 3 are housed in a pump casing consisting of a front casing 5, a rear casing 6, and an intermediate casing 7. 6, an axial flow type booster pump B having an axial flow screw type rotor 8 is directly connected to constitute a composite pump.

Axial flow threaded rotor 8 of the above booster pump B
is installed coaxially with the drive shaft 1 of the gear pump A, and is located between the casing 9 of the booster pump B and the rear casing 6 of the gear pump A, and has a volute chamber 10 therein. Section C is interposed. In addition, in the figure, 7a is a discharge port, 1
1 and 11a are bearings, and 12 is a communication channel.

During operation, when the drive shaft 1 rotates, the gear pump A
and booster pump B are driven together, and the fluid sucked in from the suction port 9a of booster pump B is pressurized by axial flow type booster pump B, rectified by volute part C, and then passed through the flow path as shown by the arrow. After 12 years,
After being guided to a suction port (not shown) of a gear pump A (usually, a suction port and a discharge port are provided on both sides of the meshing point of both gears), the pressure is increased by the gear pump A, It is designed to be discharged from the discharge port 7a.

This prevents the suction performance of the gear pump A from deteriorating when rotating at high speed or handling highly viscous fluid.

[Problem that the invention seeks to solve]

In the gear pump (compound pump) that uses the conventional axial flow pump as a booster pump, the axial flow pump as a booster pump has sufficient blade length to ensure discharge pressure, and Since it is unavoidable to reduce the backflow to the suction side as much as possible, the overall length of the gear pump with booster pump is quite long, and it has no significant effect on suction performance.

Furthermore, since the discharge flow from the axial impeller (rotor) occurs in the axial direction from the entire circumference of the impeller, the booster pump B and gear pump A are connected in the flow path 12 as shown in FIG. In order to connect the pumps, a chamber such as a swirl chamber 10 must be provided between the two pumps to reduce the pressure loss, and the flow must be collected in one place, which not only complicates the structure, but also
There was a problem that the overall length of the gear pump with booster pump was further increased.

Also, when using a mixed flow pump as a booster pump, in order to improve suction performance, the cone angle of the impeller, which is similar to that of an axial flow pump, must be made small. It was necessary to install an impeller with a long axial length.

The technical object of the present invention is to provide a compound pump that significantly increases the suction capacity of a booster pump and is lightweight and compact.

[Means for solving problems]

In order to solve the problems and technical problems of the prior art described above, the present invention provides a composite pump in which a main pump and a booster pump are integrated, with a positive displacement pump as the main pump, and a vortex pump as the booster pump. It is characterized by

[Effect]

Since the present invention is configured as described above,
During operation, when the vortex pump, which is a booster pump, is driven at the same time as the main pump is driven, the pumped liquid flowing from the suction port of the vortex pump flows through a number of grooves provided around the impeller. While generating a vortex flow in the radial direction, the pressure increases in a long passage on the circumference, and is led to the discharge port of the pump, and then continues to the inlet of the main pump consisting of a positive displacement pump via a passage provided in the casing. be led to.

In the main pump, the fluid pressurized by the vortex pump, which is the booster pump described above, is further pressurized and discharged to the outside from the discharge port of the main pump.

As mentioned above, in a vortex pump used as a booster pump, the pressure increasing action is repeatedly performed in a long passage on the circumference, so even if some air bubbles are generated due to cavitation near the suction port, the pump It has been experimentally confirmed that the gas disappears sufficiently in the middle of the passage leading to the discharge port, so the suction performance is significantly improved, especially when used as a booster pump.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a compound pump showing an embodiment of the present invention, and FIG. 2 is a partially sectional side view taken along the line - in FIG. 1 in the direction of the arrow. In FIG. 1, the same reference numerals as those shown in FIG. 3 indicate the same or similar parts.

In the figure, the main pump is driven by a drive gear 2 mounted on a drive shaft 1 supported by a bearing 11 and a driven gear 4 mounted on a driven shaft 3.
is driven by a gear pump, which performs pumping action.
There is no difference from the figure).

However, in this embodiment, an impeller 21 of the vortex pump is attached to the shaft end of the drive shaft 1, and the impeller 21 is a part of the vortex pump casing integrally formed on the outside of the rear cover 16 of the gear pump. 20
It is supported concentrically within an internal vortex pump chamber 22 .

As shown in FIG. 2, the vortex pump chamber 22 has a partition 23 that is formed on a part of the inner circumferential surface of the vortex pump casing section 20 and prevents leakage with a narrow gap between the vortex pump chamber 22 and the circumferential surface of the impeller 21. A suction port 24 and a discharge port 25 of the vortex pump are provided circumferentially adjacent to each other on both sides of the vortex pump, and the discharge port 25 forms an introduction portion of the flow path 12 to the gear pump.

During operation, when the vortex pump, which is a booster pump, is driven by the common drive shaft 1 at the same time as the gear pump, which is the main pump, the pumped liquid flowing in from the suction port 24 of the vortex pump is transferred to the impeller. It advances in the direction of the arrow in the long passage on the cylinder while generating a radial vortex flow in the numerous cut grooves 21a around the periphery of the gear pump, and during this time it is led to the discharge port 25 while being subjected to pressure increasing action, and continues to flow into the rear casing of the gear pump. 16
It is led to the inlet of the gear pump, which is the main pump, through a passage 12 provided in the main pump. In this gear pump, the fluid pressurized by the vortex pump is further pressurized and discharged to the outside from the discharge port 7a.

According to this embodiment, by using a vortex pump as the booster pump, (i) since the impeller 21 is thin, a compact gear pump with a booster pump that is slightly longer than a gear pump can be obtained. (ii) As the pressure increasing effect of the vortex pump, the pressure is increased in a long flow path from one end of the casing along the circumference of the impeller with a vortex flow, so the pressure increasing effect is large, and therefore some cavitation occurs near the suction port. Even if this occurs, the cavitation disappears on the discharge side, resulting in a booster pump with high self-priming performance. (iii) Since the discharge port 25 of the vortex pump is provided at a position on the circumference of the impeller 21, it is located eccentrically from the shaft center. It is located near the meshing point of the drive gear 4 and is also eccentric from the shaft center, so by appropriately designing the positional relationship between these two pumps, the vortex pump discharge port 25 and the gear pump suction port can be connected. can be placed close to each other and easily connected through the through hole 12, making it possible to obtain a gear pump with a booster pump having a simple and compact structure.

In the above-described embodiment, a structure in which the impeller 21 of the vortex pump is attached to the shaft end of the drive shaft 1 has been described, but the impeller 21 of the vortex pump may be attached to the tip of the driven shaft 3. Moreover, although the structure in which the impeller 21 is attached directly to the drive shaft 1 has been described, it may also be attached via a joint such as a spline, and the effect will be the same in that case.

Further, although a structure using a gear pump as the main pump has been described, other positive displacement pumps such as vane pumps may be used.

〔Effect of the invention〕

As explained above, according to the present invention, by particularly adopting a vortex pump as the booster pump of the compound pump, the suction capacity of the positive displacement pump, which is the main pump, is significantly increased, and the axial length of the compound pump as a whole is increased. can be shortened and made smaller and lighter.

In addition, since the discharge port of the vortex pump is provided at a position on the circumference of the impeller, the liquid is supplied from the vortex pump to the inlet of the main pump through a single simple passage. Therefore, the structure can be simplified and fluid loss can be reduced.

In addition, the discharge port of a vortex pump is located eccentrically from the shaft center on the circumference of the impeller. If this is adopted, the fluid connection means for both pumps can be easily constructed within the casing of the main pump or the like with a simple structure.

Additionally, in this case, while vortex pumps are suitable for use with small flow rates, positive displacement pumps including gear pumps are also used for high pressure specifications in the small flow rate range, so how to use both pumps connected in series is It has the advantage of being efficient and compatible in terms of flow rate.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a compound pump showing an embodiment of the present invention, FIG. 2 is a cross-sectional view of essential parts along the line taken along the line of FIG. 1, and FIG. 3 is a longitudinal cross-sectional view of a conventional example. DESCRIPTION OF SYMBOLS 1... Drive shaft, 2... Drive gear, 4... Driven gear, 7a... Discharge port, 12... Channel, 16...
Rear casing, 20... Vortex pump casing part, 21... Same impeller, 24... Same suction port, 25
...Same discharge port.

Claims (1)

[Scope of Claims] 1. A compound pump in which a main pump and a booster pump are integrated, wherein the main pump is a positive displacement pump and the booster pump is a vortex pump.A compound pump with a vortex pump as a booster. 2. A compound pump using a vortex pump as a booster according to claim 1, wherein the main pump is a gear pump. 3. A compound pump using the vortex pump as a booster according to claim 2, wherein an impeller of the vortex pump is provided coaxially with the driving shaft or driven shaft of the main pump. 4. The vortex pump according to claim 2, in which a vortex pump casing is formed in a part of the casing of the main pump, and a through hole is formed in the casing and connected to the suction port of the main pump, is used as a booster. compound pump. 5. The pump according to claim 2, wherein the position of the suction port of the main pump on the cross-section perpendicular to the axis and the position of the discharge port of the vortex pump on the cross-section perpendicular to the axis substantially coincide with each other in the axial direction. A compound pump with a vortex pump as a booster.