JPH07119628A - Pulsation adjusting mechanism for nonpulsating pump - Google Patents

Abstract

PURPOSE:To provide a pulsation adjusting mechanism for a nonpulsating pump capable of limiting pulsation irrespective of pump actuating conditions. CONSTITUTION:An increasing cam curve for increasing a part of the discharging flow rate of a main pump P is set on an eccentric cam and a reducing auxiliary pump (p) for adjustably reducing a part of the discharging flow rate of the main pump P is set on a driving shaft 14. The cam curve is set correcting the eccentric cam. The auxiliary pump (p) is composed of an auxiliary eccentric cam 44 including a cam 40 provided with a groove on the driving shaft 14 and engaging balls 42 and a spring back type plunger pump for reciprocating an auxiliary cross head 48 via a spring 46 (also an auxiliary plunger 54 linked there with via working oil 52 within a tube 50). A screw means 56 is provided capably of advancing and retreating on the engaging balls 42 so as to adjust the stroke length of the cross head 48 (thus the plunger 54) by engaging therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulsation-free pump composed of multiple pumps, and more particularly to improvement of a pulsation-adjusting mechanism for improving pulsation-free characteristics.

[0002]

2. Description of the Related Art Generally, a pulsation-free pump consisting of multiple pumps (hereinafter sometimes referred to as "main pump" or "pump") has flow rate waveforms as shown in FIGS.
Normally, it is formed from two pumps P1, P2 (Fig. 6) or three pumps P1, P2, P3 (Fig. 7), and these pumps have a common suction pipe, discharge pipe and drive shaft. 180 ° (2
It is configured to be driven by a phase difference of 120 ° (triple type) or 120 ° (triple type). And in this case, two consecutive
By synthesizing a part of the discharge flow rates of the three pumps (for example, P1 and P2 in the triple type) sequentially, the combined discharge flow rate q is always constant, that is, no pulsation is achieved. There is. In addition, the pump itself can be suitably configured by an ordinary reciprocating pump, particularly a hydraulic diaphragm pump.

However, in such a pulsation-free pump, it is actually difficult or impossible to achieve pulsation-free accurately for the following reasons. That is, first of all, in this type of non-pulsating pump, it is unavoidable that air is mixed in the liquid contact part and the hydraulic drive part. However, if air is mixed in this way, the pump (main pump) Even if is activated, the air is compressed at the discharge start point, so it takes time to reach the discharge pressure, while the air is expanded at the suction start point until the suction negative pressure is reached. It takes time. Therefore, for example, in the triple-type pulsation-free pump shown in FIG. 8, two pumps whose discharge flow rates are combined, for example, both P1 and P2 should be discharge processes, in other words, the subsequent pumps in both pumps. At the point A where the phase side pump P2 should be shifted from the suction process to the discharge process (hereinafter referred to as the discharge transition point) A, the subsequent phase side pump P2 has a discharge delay (discharge pause process) as shown in FIG. At the same time as Δt1 is generated, a discharge flow rate defect amount Δq1 is generated.

Secondly, in this type of non-pulsating pump, a play in the drive portion or a delay in the operation of the check valve is unavoidable, but if such a play is present, The subsequent phase side pump P2 moves in a direction in which the force is applied to either the front or rear shaft portion of the play, which causes another discharge delay Δt2 as shown in FIG. Then, another discharge flow rate deficiency Δq2 is similarly generated.

As described above, in this type of non-pulsating pump, as generally shown in FIG. 10, one of the two main pumps P1 and P2 that synthesizes a part of the discharge flow rate has the subsequent phase side pump P2. Due to the inclusion of air, mechanical play, or the like, the discharge flow rate deficiency Δq = Δq1 + Δq2 is generated during the discharge suspension process Δt = Δt1 + Δt2, so that accurate pulsation cannot be achieved.

Therefore, in order to solve the above-mentioned problems, in the step ΔT immediately before the above-mentioned discharge transition point A (hereinafter referred to as a preliminary step) ΔT, the discharge flow rate correction amount ΔQ (FIG. 10) corresponding to the above-mentioned discharge flow rate defect amount Δq (FIG. 10). ) Has been developed and has been put into practical use. Therefore, according to this type of conventional technology, the discharge flow rate correction amount ΔQ is generated after the time corresponding to the discharge pause process Δt and the discharge flow rate defect amount Δq is erased, so that complete pulsation is achieved.

[0007]

However, the above-mentioned prior art still has the following drawbacks.

That is, according to the above-mentioned prior art, as described above, since the defective portion of the discharge flow rate is erased by the correction portion, accurate pulsation is achieved. However, the pulsation-free or the erasure by the correction of the defect is achieved only under a constant operating condition of the pulsation-free pump. That is, the deficient portion fluctuates depending on the operating condition of the pump, particularly the discharge pressure, while the correction amount is maintained at a constant discharge amount without being substantially affected by the operating condition of the pump. It Therefore, in the above-mentioned conventional technique, when the operating condition of the pump is changed, a difference occurs between the defective amount of the discharge flow rate and the corrected amount, and the pulsation is unavoidable. It should be noted that this pulsation can be avoided by providing a special pulsation removing device, but it goes without saying that this method requires a great deal of cost and space.

Therefore, an object of the present invention is to prevent the pulsation of the pump discharge flow rate, which is caused by the inclusion of air, mechanical play, etc., regardless of the pump operating conditions, without causing any pulsation of the pulsation-free pump. It is to provide an adjusting mechanism.

[0010]

In order to achieve the above object, a pulsation adjusting mechanism for a pulsation-free pump according to the present invention comprises a common suction pipe, a discharge pipe and a drive shaft, each of which is provided with a drive cam mechanism. In a pulsation-free pump configured to sequentially combine a part of the discharge flow rates of a pair of pumps, the drive cam includes one of the discharge flow rates of the multiple pumps. The increasing cam curve for increasing the number of parts is provided, and the drive shaft is provided with a decreasing auxiliary pump for decreasing a part of the discharge flow rate of the multiple pumps, and the increasing and decreasing is performed by the drive cam and the decreasing auxiliary pump having the increasing cam curve. With the combined correction of the discharge flow rates, the pump on the subsequent phase side of one of the pair of multiple pumps that synthesizes a part of the discharge flow rate can adjust the flow rate loss amount generated during the discharge pause process. Characterized by configured to positive.

In this case, the increasing cam curve of the drive cam can be set so that the discharge flow rate of the subsequent phase side pump is increased by a certain amount in correspondence with the discharge suspension process.

Further, the reduction auxiliary pump is composed of a spring-back type plunger pump which reciprocates through an auxiliary eccentric cam composed of a grooved cam provided on the drive shaft and an engaging ball, and the engaging ball is provided with this. Screw means for adjusting the stroke length of the plunger by engaging with, and thereby performing suction and discharge respectively during the discharge process and the suction process of the subsequent phase side pump, and adjusting the discharge flow rate of the following phase side pump. It can be configured to reduce as much as possible.

[0013]

According to the present invention, the subsequent phase-side pump increases the amount of discharge flow loss caused by air mixing or mechanical play, that is, the discharge flow amount deficiency generated during the discharge pause process, which is set in the drive eccentric cam. The increase / decrease correction amount of the discharge flow rate generated from the cam curve (hereinafter sometimes simply referred to as cam curve) and the reduction auxiliary pump (hereinafter sometimes simply referred to as auxiliary pump) provided on the drive shaft are combined. The flow rate can be adjusted so that it can be erased by the combined correction amount. In other words, the pulsation of the pump discharge flow rate that occurs due to air mixing and mechanical play, etc., via the cam curve and the auxiliary pump, regardless of the pump operating conditions, that is, regardless of the fluctuation of the pulsation. , Surely deterred.

The auxiliary pump in the present invention is
Since it can be driven by the same hydraulic mechanism as the main pump, it can be configured relatively easily, and discharge and suction are performed in reverse during the suction and discharge steps of the main pump, reducing the load and increasing the service life. It has the advantage that it can be realized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of a pulsation adjusting mechanism for a pulsationless pump according to the present invention will be described in detail below with reference to the accompanying drawings. For convenience of explanation, the same components as those of the conventional configuration shown in FIGS. 6 to 10 are designated by the same reference numerals, and detailed description thereof will be omitted.

First of all, the basic structure of the pulsation-free pump itself according to the present invention is the same as that of the conventional one described above. That is, FIG. 1 and FIG. 2 show a double hydraulic diaphragm type pulsationless pump as an example. This pulsation-free pump will be briefly described with reference to FIG. 6 described above, and double pumps (main pumps) P1 and P2 will be described.
Is a common suction pipe 10, a discharge pipe 12, and a drive shaft 1.
4, eccentric (cylindrical) cam 16, cross head 18
And driven via the plunger 20 with a phase difference of 180 °. And thereby, the suction check valve 22
The fluid in the pump chamber 26 defined between the discharge check valve 24 and the discharge check valve 24 is discharged through the hydraulic chamber 28 and the diaphragm 30, and a part of these discharge flow rates is sequentially combined to obtain a constant combined flow rate. It is configured such that q is obtained, that is, a pulsating pumping operation is achieved. The structure and operation of the triple continuous pulsation pump can be easily analogized with reference to FIG.

According to the present invention, however, in the above-mentioned structure, the drive eccentric cam 16 is set with an increasing cam curve for increasing a part of the discharge flow rate of the main pump, and the drive shaft 1 is provided.
4 is provided with a reduction auxiliary pump p for reducing a part of the discharge flow rate of the main pump.

Therefore, first, the increasing cam curve set on the eccentric cam 16 will be described. This can be suitably achieved by the above-mentioned conventional technique. That is, as shown in FIG. 3 corresponding to the characteristic diagram for explaining the discharge flow rate defect Δq generated in the subsequent phase side pump P2 of the triple pump of FIG. 10, the discharge flow rate defect Δq is shown.
To correct and / or change the shape and / or rotation speed of the eccentric cam 16 of the succeeding phase side pump P2 in the preliminary step ΔT immediately before the discharge transition point A of the succeeding phase side pump P2. Thus, it can be generated so as to correspond to the discharge suspension process Δt of the subsequent phase side pump P2. The absolute value of the increase correction amount ΔQ1 is set to be larger than that of the loss amount Δq.

Next, the reducing auxiliary pump p provided on the drive shaft 14 includes an auxiliary eccentric cam 44 formed by a grooved cam 40 and an engaging ball 42 provided on the drive shaft 14, and a spring 4.
The auxiliary crosshead 48 (and the auxiliary plunger 54 continuous to the auxiliary crosshead 48 via the hydraulic oil 52 in the tube 50) is reciprocated by a springback type plunger pump. The engagement ball 42 is provided with a screw means 56 that engages with the engagement ball 42 and adjusts the stroke length of the cross head 48 (and thus the plunger 54) so as to be able to move back and forth. Thereby, the auxiliary pump p achieves suction and discharge, respectively, during the discharge and suction steps of the main pump P, that is, retracts and advances the plunger 54, respectively, and adjusts the discharge flow rate of the main pump P by an adjustable amount. Is configured to.
Since the hydraulic oil 52 in the tube 50 cooperates with the hydraulic oil in the hydraulic chamber 28, the plunger 5 in the tube 50 is
4 is not always necessary. In addition, the cross head 48
Is pushed back from the discharge pressure of the main pump P separately from the spring 46, so the strength of the spring 46 may be small.

As described above, in the auxiliary pump p of the present invention, in FIG. 4 (corresponding to FIG. 3 and FIG. 10 described above), the discharge flow rate reduction correction amount ΔQ2 is changed to the subsequent phase side pump P.
In the preliminary process ΔT immediately before the discharge transition point A of 2 (corresponding to the discharge suspension process Δt), the flow rate can be adjusted so that it can be generated. Therefore, according to the present invention, as also shown in the corresponding FIG. 5, the increase correction amount ΔQ1 generated from the cam curve and the decrease correction amount ΔQ2 generated from the auxiliary pump.
By the combined correction amount (ΔQ1 + ΔQ2) with the above, the discharge flow rate defect amount Δq can be completely eliminated. In addition, in this case, even if the operating condition (discharge pressure) is changed and the defect amount Δq fluctuates, a combined correction amount (ΔQ1
Since + ΔQ2) can be easily adjusted via the decrease correction amount ΔQ2, the erasing can be easily and completely achieved as described above.

As described above, according to the present invention, it is possible to reliably suppress the pulsation of the pump discharge flow rate, which is caused by the inclusion of air, mechanical play, etc., regardless of the pump operating conditions. Further, since the auxiliary pump according to the present invention is driven by the hydraulic mechanism common to the main pump, the auxiliary pump can be configured relatively easily and, at the same time, during the suction process and the discharge process of the main pump, the discharge and the suction can be reversed. Therefore, there is an advantage that the load is reduced and the life is extended.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and many design changes can be made without departing from the spirit thereof.

[0023]

As described above, the pulsation adjusting mechanism of the pulsationless pump according to the present invention is provided with the common suction pipe, discharge pipe and drive shaft, and is driven with a predetermined phase difference via the drive cam mechanism. In a pulsation-free pump configured to sequentially combine a part of the discharge flow rates of a pair of pumps, an increasing cam curve for increasing a part of the discharge flow rate of the multiple pumps in a drive cam. And a reduction auxiliary pump that reduces a part of the discharge flow rate of the multiple pumps is provided on the drive shaft, and a combined correction amount of the discharge flow rates increased and decreased by the drive cam and the reduction auxiliary pump having the increasing cam curve is set. , One of the pair of multiple pumps that synthesizes a part of the discharge flow rate is configured to correct the discharge flow rate deficiency that occurs during the discharge pause process so that the flow rate can be adjusted. And it makes it possible to suppress the pulsation of the pump delivery rate caused by the aeration and mechanical clearance such, reliably irrespective of the pump operating conditions. In addition, the auxiliary pump of the present invention can be driven by a hydraulic mechanism common to the main pump, and discharge and suction are performed in reverse during the suction process and the discharge process of the main pump, so that the auxiliary pump can be configured relatively easily. At the same time, the load is reduced and a longer life can be achieved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a pulsation adjusting mechanism of a pulsation-free pump according to the present invention.

FIG. 2 is a cross-sectional view of essential parts showing the configuration of an auxiliary pump in the pulsation adjusting mechanism of the pulsation-free pump shown in FIG.

FIG. 3 is a characteristic diagram showing a correction amount of a discharge flow rate increase due to an action of a drive cam in the pulsation adjusting mechanism of the pulsation-free pump shown in FIG.

FIG. 4 is a characteristic diagram showing a correction amount of a discharge flow rate reduction by an action of an auxiliary pump in the pulsation adjusting mechanism of the pulsation-free pump shown in FIG.

5 is a characteristic diagram showing a discharge flow rate combined correction amount by the action of a drive cam and an auxiliary pump in the pulsation adjusting mechanism of the pulsation-free pump shown in FIG.

FIG. 6 is a characteristic diagram showing flow rate waveforms of respective pumps of a general dual continuous pulsation pump and their combined waveforms.

FIG. 7 is a characteristic diagram showing flow rate waveforms of respective pumps of a general triple-type pulsation-free pump and combined waveforms thereof.

FIG. 8 is a characteristic line showing a flow waveform of each pump and a composite waveform thereof for explaining a discharge delay (pausing process) due to air mixing that occurs in a general triple-type non-pulsating pump and a discharge flow defect due to the discharge delay. It is a figure.

FIG. 9 shows flow rate waveforms of respective pumps and their combined waveforms for explaining a discharge delay (pause step) due to mechanical play or the like that occurs in a general triple-type non-pulsating pump, and a discharge flow rate defect due to this. It is a characteristic diagram shown.

FIG. 10 is a flow rate waveform of each pump for explaining a discharge delay (pausing step) due to air mixing and mechanical play generated in a general triple-type non-pulsating pump, and a discharge flow amount deficiency due to the delay. It is a characteristic diagram graph which shows a synthetic waveform.

[Explanation of symbols]

 10 Suction pipe 12 Discharge pipe 14 Drive shaft 16 Eccentric (cylindrical) cam 18 Crosshead 20 Plunger 22 Suction check valve 24 Discharge check valve 26 Pump chamber 28 Hydraulic chamber 30 Diaphragm 40 Grooved cam 42 Engaging ball 44 Auxiliary eccentric cam 46 Spring 48 Auxiliary Cums Head 50 Tube 52 Hydraulic Oil 54 Auxiliary Plunger 56 Adjusting Screw

Claims (3)

[Claims] 1. A multiple pump having a common suction pipe, a discharge pipe and a drive shaft, each driven by a predetermined phase difference via a drive cam mechanism. A part of the discharge flow rate of a pair of pumps is sequentially arranged. In a pulsation-free pump configured to combine, an increase cam curve that increases a part of the discharge flow rate of the multiplex pump is set in the drive cam, and a part of the discharge flow rate of the multiplex pump is reduced in the drive shaft. A reduction assist pump is provided to cause the drive cam having the increasing cam curve and the decrease correction pump to increase / decrease the combined correction amount of the discharge flow rate, and a subsequent phase of one of the pair of multiple pumps that combines a part of the discharge flow rate. A pulsation adjusting mechanism for a pulsation-free pump, wherein the side pump is configured to correct a discharge flow rate deficiency generated during the discharge pause process so that the flow rate can be adjusted. 2. The pulsation of the pulsation-free pump according to claim 1, wherein the increasing cam curve of the drive cam is set so that the discharge flow rate of the subsequent phase side pump is increased by a certain amount in response to the discharge suspension step. Adjustment mechanism. 3. The reduction assist pump comprises a spring-back type plunger pump that reciprocates via an auxiliary eccentric cam consisting of a grooved cam and an engaging ball provided on the drive shaft, and the engaging ball has Screw means for adjusting the stroke length of the plunger by engaging with, and thereby performing suction and discharge respectively during the discharge process and the suction process of the subsequent phase side pump, and adjusting the discharge flow rate of the following phase side pump. The pulsation adjusting mechanism for a pulsationless pump according to claim 1, wherein the pulsation adjusting mechanism is configured so as to be reduced as much as possible.