JPH04111586U - multistage pump - Google Patents

Abstract

(57) [Summary] [Purpose] In a multi-stage pump that increases liquid pressure step by step using multiple pumps, due to the difference in capacity efficiency between the front-stage pump A and the rear-stage pump B, the discharge pressure of the front-stage pump A during unloading P ₁ This eliminates the pressure reversal phenomenon in which the discharge pressure P ₂ of the downstream pump B becomes higher than the discharge pressure P 2 of the downstream pump B, thereby saving energy and reducing noise. [Structure] A bypass path with a check valve 29 interposed is provided between the discharge side of the front stage pump A and the discharge side of the rear stage pump B. The check valve 29 controls the discharge pressure P ₁ of the front stage pump A.
When the discharge pressure P _{2 of the downstream pump B becomes greater than the discharge pressure P 2} , the bypass path is opened. By operating the check valve 29, the difference in discharge flow rate caused by the difference in capacity efficiency between the front pump A and the rear pump B is eliminated, and the pressure reversal phenomenon during unloading is eliminated.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is a multi-stage pump used as a high-pressure pump for general industry and ships, for example. Regarding the pump.

0002

[Conventional technology]

A multistage pump uses multiple pumps to increase fluid pressure step by step. There are a large number of types, as many different types are used. Conventional multi-stage port Figure 1 schematically shows a pump using an internal gear pump.

[0003] Internal gear pumps are connected in two stages, and both the front stage pump A and the rear stage pump B have a pinion gear 2 rotated by a drive shaft 1, and a ring gear fitted externally and partially meshing with the pinion gear 2. 3, and a partition plate 4 with a crescent-shaped cross section that seals both tooth spaces, and as the pinion gear 2 rotates, the discharge pressure _P1 of the front stage pump A is doubled to _P2 at the rear stage pump B. Pressure and supply to the load side. In FIG. 1, for convenience of explanation, the front-stage pump A and the rear-stage pump B are shown separately, but in an actual multi-stage pump, they share a drive shaft 1 and are connected in the axial direction.

0004

[Problem that the idea aims to solve]

In such conventional multi-stage pumps, even if the front-stage pump A and the rear-stage pump B have the same specifications, it is inevitable that there will be a slight difference in volumetric efficiency between the two. Let Q ₁ be the discharge flow rate of the front stage pump A and Q ₂ be the discharge flow rate of the rear stage pump B. If Q ₁ > Q ₂ , even if the discharge pressure P ₂ of the rear stage pump B becomes 0 during unloading, the front stage pump The discharge pressure P ₁ of pump A does not become zero, and a pressure corresponding to the discharge flow rate is generated. This pressure reversal phenomenon means that even if the final discharge pressure is apparently zero, extra energy is consumed inside the pump, resulting in wasted operating energy. Additionally, if the pump is operated in this condition, it will generate noise comparable to when operating under high pressure load, even though it is unloading.

[0005] The purpose of this invention is to prevent energy consumption inside the pump during unloading. Our objective is to provide an energy-saving, low-noise multi-stage pump.

[0006]

[Means to solve the problem]

The multistage pump of this invention is a multistage pump that increases fluid pressure step by step using multiple pumps. to ensure that the discharge pressure of the front stage pump does not exceed the discharge pressure of the rear stage pump. , a check valve is installed between the discharge side of the front stage pump and the discharge side of the rear stage pump. It is characterized by

[0007]

[Effect]

If the discharge pressure of the front stage pump exceeds the discharge pressure of the rear stage pump during unloading, the The Eck valve operates to eliminate this pressure reversal phenomenon. When it comes to road driving, The discharge pressure of the stage pump exceeds the discharge pressure of the previous stage pump, and the check valve returns to its original steady state. Return to

[0008]

【Example】

Embodiments of the present invention will be described below based on the drawings. Figure 2 shows a large number of cases in which the present invention was implemented. FIG. 3 is a vertical cross-sectional view showing the overall structure of an example of a stage pump, and FIG. 4 is a view along the Y-Y line in FIG. 3, and FIG. 5 is a view along the Y-Y line in FIG. FIG. 2 is a circuit diagram schematically showing a circuit configuration of a multistage pump.

0004 The multi-stage pump shown here has an internal gear pump axially arranged as shown in Figure 2. This is a high-pressure pump that combines two stages. This pump is axially polymerized It has four housings 11-14. The housings 11 and 12 are for the front stage pump A. The housings 13 and 14 constitute a rear pump B. The drive shaft 15 is It is supported by the housing 11 via a bearing 16. Pinion gear of front stage pump A 17 is attached to approximately the center of the drive shaft 15 and is attached to the housing 12. It meshes with the ring gear 18 which is rotated. The pinion gear 19 of the rear pump B is It is attached to the tip of the moving shaft 15 and attached to the ring gear 20 attached to the housing 13. They mesh together.

[0005] The liquid flows from an inlet 21 provided in the housing 11 to a suction provided in the housing 12. After entering the chamber 22 and pressurizing it, it enters the rear pump B from the discharge chamber 23 in the housing 12. . In the latter stage pump B, pressure is applied from the suction chamber 24 in the housing 13 to the discharge chamber 25. It moves while moving, and is discharged to the outside of the pump from a discharge port 26 provided in the housing 14.

[0006] A housing in which the pinion gear 19 and ring gear 20 of the rear pump B are incorporated. As shown in FIGS. 3 and 4, the ring 13 has a suction chamber 24 and a discharge chamber 25 communicating with each other. Bypass paths 27 and 28 are provided between the bypass paths 27 and 28. A check valve 29 is interposed.

[0007] The check valve 29 normally closes the flow path with the biasing force of a spring 30 and prevents suction. The flow path is opened only when the pressure in the chamber 24 becomes higher than the pressure in the discharge chamber 25. Ru. 31 is a plug screwed into the housing 13 to hold the spring 30 , 32 are partition plates having a crescent-shaped cross section. 33 is installed at the exit of the bypass path 28. The vertical orifice connects the suction chamber 24 to the discharge chamber 25 through the bypass passages 27 and 28. The amount of liquid flowing in is determined by the pressure between the front pump 1 and the rear pump B that occurs during unloading. This is to adjust to the flow rate difference due to reverse rotation.

[0008] In a multi _- stage pump having such a configuration, during normal load operation, as shown in _{FIG .} The pressure is increased to output. The suction chamber 24 provided in the housing 13 of the rear pump B is directly connected to the discharge chamber 23 provided in the housing 12 of the front pump A, so it receives a discharge pressure of P ₁ , and that P ₁ is connected to the discharge chamber 25 . Since the discharge pressure P ₂ is smaller than the discharge pressure P 2 , the check valve 29 shuts off the bypass paths 27 and 28 . Therefore, normal road operation is performed.

[0009] During unloading (when P ₂ = 0), a difference in discharge flow rate occurs due to the difference in volumetric efficiency between the front pump A and the rear pump B, and as a result, the discharge pressure P ₁ of the front pump A is lower than that of the rear pump B. When the discharge pressure of pump B becomes higher than P ₂ (=0), check valve 29 is activated and bypass paths 27 and 28 are opened. As a result, an amount of liquid corresponding to the discharge flow difference flows from the suction chamber 24 to the discharge chamber 25 through the bypass paths 27 and 28, and the pressure reversal phenomenon between the front pump A and the rear pump B is eliminated. As a result, there is no wastage of operating energy in the front stage pump A, resulting in energy savings, and the noise is reduced to the normal unloading level.

0010 Note that the above embodiment has a configuration in which a two-stage internal gear pump is combined. , but is not limited to this, and is also suitable for multi-stage pumps that combine three or more stage pumps. It is also applicable to multi-stage pumps using pumps other than internal gear pumps. You can also Furthermore, the check valve is built into the inside of the pump. However, it may be connected to the pump via external piping.

[0011]

[Effect of the idea]

As is clear from the above explanation, the multi-stage pump of the present invention can avoid problems with this type of pump. A simple structure eliminates the pressure operation phenomenon during unloading due to the unobtainable difference in volumetric efficiency. Prevents energy waste and noise increase due to pressure reversal phenomenon, resulting in energy savings and This is highly effective in reducing noise and noise.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the structure of a conventional multistage pump.

[Fig. 2] An example of a multistage pump implementing the present invention,
FIG. 2 is a vertical cross-sectional view showing the overall structure.

FIG. 3 is a view taken along the line X--X showing the main parts of the multistage pump shown in FIG. 2;

FIG. 4 is a view taken along line BB in FIG. 3;

FIG. 5 is a circuit diagram schematically showing the circuit configuration of the multistage pump of FIG. 2;

[Explanation of symbols]

A Front stage pump B Post-stage pump 15 Drive shaft 17,19 Pinion gear 18,20 Ring gear 24 Suction chamber of rear stage pump B 25 Discharge chamber of rear pump B 27, 28 bypass road 29 Check valve 33 Orifice

Claims (1)

[Scope of utility model registration request] Claim 1: In a multi-stage pump that increases liquid pressure in stages using a plurality of pumps, the discharge side of the front-stage pump and the discharge side of the rear-stage pump are connected so that the discharge pressure of the front-stage pump does not exceed the discharge pressure of the rear-stage pump. A multistage pump characterized by a check valve interposed between the pumps.