JPH06147102A - Multi-connection type non-pulsation fixed quantity pump - Google Patents

Abstract

PURPOSE:To remove pulsation by preventing the opening/closing of suction/ discharge valves from being delayed, in the case of a multi-connection type reciprocation pump (plunger, diaphragm, bellows or the like) in which plunger or the like speed is controlled so that the sum of flow discharged from each pump may become fixed at all times. CONSTITUTION:A section in which a plunger or the like is stopped within a fixed range and discharge or suction is not conducted at all at the time of each pump entering into a discharge stroke from a suction stroke and entering into a suction stroke from a discharge stroke, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous type pulsationless metering pump.

[0002]

2. Description of the Related Art A multi-reciprocating reciprocating pump in which the speed of a plunger or the like is controlled so that the sum of the flow rates discharged from respective pumps is always constant is known. A case of a triple plunger pump having a velocity curve as shown in FIG. 5 will be described by way of example. A shutoff valve is provided at the discharge port of this pump to forcibly build up the pressure. When a pressure gauge is provided between the discharge port and the change and the change is recorded on the chart paper, the result is as shown in FIG. That is, one rotation of the pump causes six pulsations. When this is compared with the rotation angle of the cam, it becomes as shown in FIG. 3 plungers A, B,
C

[0003] Becomes That is, pulsation occurs at the start of discharge and the start of suction of each plunger. This occurs because the opening / closing timing of the intake / exhaust valve is delayed compared to the movement of the plunger. This will be described in detail with reference to FIG.

FIG. 8 (a) shows the state of the valve at the time of discharge, in which the discharge valve (Vd) is open and the suction valve (Vi) is closed.
FIG. 8B shows the state of the valve at the end of discharge, in which the discharge valve (Vd) is slightly open and the suction valve (Vi) is closed. The state at the start of inhalation is shown in Fig. 8 (c).
d) is not completely closed, and the intake valve (Vi) is also slightly open. The state at the time of inhalation is shown in FIG. 8 (d), in which the discharge valve (Vd) is closed and the suction valve (Vi) is open. The state at the end of suction is shown in Fig. 8 (e), and the discharge valve (Vd)
Is closed and the intake valve (Vi) is slightly open. The state at the start of discharge is shown in FIG. 8 (f), in which the discharge valve (Vd) is slightly open and the suction valve (Vi) is not completely closed.

In the above processes, the cause of pulsation is the condition of and. In other words, the process of (Fig. 8
In (c)), since the discharge valve (Vd) is not completely closed even at the start of suction, backflow occurs from the outside of the discharge valve (Vd), the flow rate of the entire pump drops momentarily, and the pressure drops. . Further, in the step (Fig. 8 (f)), the liquid in the pump is instantaneously pushed to the outside of the suction valve (Vi), which also reduces the total flow rate.

[0006]

Conventionally, since the occurrence of such pulsation has not been completely understood, it has been impossible to completely eliminate the pulsation although various measures have been taken.

Therefore, an object of the present invention is to eliminate pulsation, and for that purpose, it is an object to prevent delay in opening / closing of the valve.

[0008]

SUMMARY OF THE INVENTION The present invention is a multiple reciprocating pump in which the speed of a plunger or the like is controlled so that the sum of the flow rates discharged from the pumps is always constant. It is characterized in that the plunger or the like is stopped within a certain range when entering the discharge step from the suction stroke and when entering the suction step from the discharge stroke, and has a section in which neither discharge nor suction is performed.

[0009]

According to the present invention, the mechanism for preventing the opening / closing of the valve from being delayed causes the plunger to be completely stationary for a certain period of time during the above strokes and strokes.
Considering the stroke from to, when the plunger is stationary at the top dead center in the state, the suction valve is closed and the total flow rate does not decrease. Further, since the pressure is the same inside the pump and outside the discharge valve, the valve ball spontaneously falls due to its own weight. Therefore, both intake and exhaust valves are completely closed while the plunger is stationary. Since the discharge valve is completely closed when the next state is entered, the liquid enters the suction stroke () without backflow.

When considering the process from to,
When the plunger is stopped at the bottom dead center in this state, the flow velocity in the pump also becomes zero, the valve ball of the suction valve naturally falls under its own weight, and both the suction and discharge valves are completely closed. In this case, since the discharge valve is closed, the total discharge amount of the pump is not affected. When the next state is entered, the suction valve is completely closed, so that all the liquid in the pump is pushed out of the discharge valve. That is, the state of FIG. 7 (g) is obtained without going through (FIG. 7 (e)) to (FIG. 7 (f)).

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the velocity curve of a plunger that moves as described above is shown in FIG. This is an example in which the plunger is stationary for 10 ° in the rotation angle of the cam in the case of the cam drive, but theoretically, it may be any number of times as long as the valve ball has time to completely close. Further, in order to increase the closing speed of the valve ball, a spring may push the valve ball.
The velocity curve in which the plunger is moving need only be constant in any combination. Also,
The number of stations is 2 or more, and may be any number. However, when it comes to actual production, considering the economic efficiency, the limit is about 5 stations. Further, in consideration of performance, the double stroke type has a problem that the suction stroke is shorter than the discharge stroke, so that shortage of suction is likely to occur, and the suction stroke is intermittent so that the flow meter cannot be attached to the suction side. Therefore, the triple type is the best.

The present invention is not limited to the plunger pump described above as long as it is a reciprocating type, and can be implemented by a diaphragm pump, a bellows pump, a piston pump or the like. In addition, the cam drive mode of the pump is normally one cam (flat cam) for one plunger (Fig. 2).
(a)) Three plungers can be arranged radially and driven by one cam (Fig. 2 (b)), or the cam can be processed on the swash plate to make it an axial type (Fig. 2 (c)). .

FIG. 3 exemplifies a specific structure when applied to the axial type. As shown in FIG. 3, three plungers (2) are housed in a housing (1) in a predetermined phase and slidably in an axial direction. Each plunger (2) has a small diameter part (2a) whose tip enters the pressurizing chamber (3) during the discharge stroke to the right in the figure, and a large diameter part (2b) carrying a steel ball (4) at its rear end. ) And are respectively supported by bearings (5, 6). The steel ball (4) carried by the plunger (2) is engaged with the cam groove (8a) of the cam plate (8) fixed to the rotating shaft (7). Although not shown in the drawing, the engagement relationship between the steel ball (4) and the cam groove (8a) is maintained by a normal return mechanism using a spring, hydraulic pressure, or the like. The outer diameter and side surface of the cam plate (8) are guided by bearings (9, 10) fixed to the housing (1).
The bearing (9) may be omitted. The cam groove (7a) is
As shown in FIGS. 4 (a) and 4 (b), the depth (s) for a predetermined rotation angle (θ) is set so that the plunger (2) draws a velocity curve as shown in FIG. Has been done. The rotating shaft (7) is supported by the housing (1) via bearings (11, 12), and is connected to a driving means such as an electric motor at a shaft end protruding outside the housing (1). A normal suction valve (Vi) and a discharge valve (Vd) are attached to the pressurizing chamber (3). In the illustrated example, suction into the three pressurizing chambers (3) and three pressurizing chambers (3) are performed. ) The passage for integrating the discharge from the housing (1) without the use of external piping
It is formed inside.

In this embodiment, for example, the structure is more compact than the structure in which three cam plates are mounted on the same shaft at a predetermined phase and arranged in parallel to drive three plungers, and the assembling and adjustment are easy. Has the advantage that

[0015]

As described above, in the cam type pulsationless metering pump of the present invention, the plunger and the like are kept constant when each pump enters the discharge stroke from the suction stroke and enters the suction stroke from the discharge stroke. Since there is a section that stops within the range and does not perform discharge or suction at all, it is possible to prevent delay in opening / closing of the valve and eliminate pulsation.

[Brief description of drawings]

FIG. 1 is a velocity diagram for explaining the operation of the present invention.

FIG. 2 is a schematic diagram showing various forms of cam drive.

FIG. 3 is a longitudinal sectional view of an axial pulsation-free pump showing an embodiment of the present invention.

4 is a side view ((a)) and a front view ((b)) of the cam plate shown in FIG.

FIG. 5 is a velocity diagram for explaining a conventional technique.

FIG. 6 is a graph showing changes in pressure with rotation angle.

FIG. 7 is a graph showing changes in pressure with rotation angle.

FIG. 8: Schematic diagram of the plunger pump in each stroke

[Explanation of symbols]

 1 Housing 2 Plunger 3 Pressurizing Chamber 4 Steel Ball 7 Rotating Shaft 8 Cam Plate 8a Cam Groove Vi Suction Valve Vd Discharge Valve

Claims (1)

[Claims] 1. In a multi-reciprocating reciprocating pump in which the speed of a plunger or the like is controlled so that the sum of the flow rates discharged from each pump is always constant, each pump enters a discharge stroke from a suction stroke. A continuous type pulsationless metering pump having a section in which the plunger or the like stops in a certain range at the time of entering the suction process from the discharge process and does not discharge or suck at all.