JPH0623747Y2 - Flow control mechanism of plunger pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flow rate adjusting mechanism in a plunger pump in which a plunger reciprocates in a pumping cylinder to transport a liquid. More specifically, it has a simple structure and The present invention relates to a mechanism capable of precisely adjusting a flow rate.

2. Description of the Related Art As a metering pump, for example, a plunger pump as shown in FIG. 6 is known. That is, in the plunger pump 1 shown in FIG. 6, 2 is a pump head, 3 is a passage for transporting liquid formed in the pump head 2 in a substantially vertical direction, and 4 and 5 are arranged below and above the passage 3, respectively. A pair of check valves 10 each of which is provided with valve seats 6 and 7 and balls 8 and 9 for controlling the transport liquid to flow only in the passage 3 from the lower side to the upper side is provided in the pump head 2. A pumping cylinder portion 11 formed so as to communicate with 3 is a plunger that is inserted into the pumping cylinder portion 10 in a liquid-tight manner and is movable back and forth by a packing 12. In this pump 1, a constant amount is produced by the reciprocating movement of the plunger 11. Liquid from the lower check valve 4 to the passage 3
It is introduced into the inside of the pump and is discharged to the outside of the pump through the upper check valve 5.

Conventionally, in the plunger pump of the type described above,
In order to reciprocate the plunger and adjust the stroke length of the plunger to adjust the flow rate of the transport liquid, a reciprocating mechanism and a flow rate adjusting mechanism as shown in FIG. 6 are usually employed.

That is, reference numeral 13 in the drawing denotes a spring locking plate vertically fixed to the plunger base side projecting outward from the pump head 2, and 14
Is a pressing spring interposed between the spring locking plate 14 and the pump head 2, and the pressing force of the pressing spring 14 always urges the plunger 11 toward its proximal end side. The lower end of the spring locking plate 13 projects to the position above the stop plate of the stop device described later. Further, 15 is a roller rotatably attached to the proximal end portion of the plunger 11, 16 is a rotary eccentric disc cam arranged in the vicinity of the roller 15, and the disc cam 16 is rotated by a motor or the like. When rotated around the shaft 17, the cam 1
The side portion of the cam 16 presses the roller 15 toward the plunger tip in response to the eccentric rotation of the plunger 6, thereby causing the plunger 11 to move.
Moves forward against the urging force of the spring 14, and after the plunger 11 reaches the most advanced position, the urging force of the spring 14 causes the roller 15 to contact the side of the cam 16 while the cam 16 moves.
The plunger 11 retreats in response to the rotation of the plunger 16. Therefore, the reciprocating movement of the plunger is performed by the cooperation of the pressing force by the rotational movement of the cam 16 and the urging force of the spring 14.

Further, X is a stop device for adjusting the backward limit position of the plunger 11. In the stop device X, a pair of side plates 19 and 20 are vertically provided on the base 18 so as to face each other along the axial direction of the plunger 11, and the side plates 19 and 20 have screw holes 2 respectively.
1, 22 are drilled. Furthermore, these screw holes 21,
A long screw rod 23 is screwed into the member 22 in a state of penetrating the side plates 19 and 20, respectively.
A stop plate 24 is fixed between the side plates 19 and 20 and is in contact with the lower part of the side surface of the plunger base of the spring locking plate 13 whose upper part is fixed to the plunger 11.
A handle 26 having a knob 25 is fixed to one end of the screw rod 23, and the screw rod 23 is moved forward or backward along the axial direction of the plunger 11 by rotating the handle 26. . In the stop device X, as described above, the side surface of the spring locking plate 13 fixed to the plunger 11 in the plunger retreating direction abuts on the stop plate 24. It stops when it comes into contact. Therefore, when the flow rate of the pump 1 is adjusted, the last retracted position of the plunger 11 is appropriately determined by moving the screw rod 23 forward or backward to stop the stop plate 24 at an appropriate position, and thereby the stroke length of the plunger 11 is determined. To adjust.

Problems to be Solved by the Invention In the conventional plunger pump described above, the plate cam 1
6, the forward limit position of the plunger 11 is determined, and the backward limit position of the plunger 11 is determined by the stop device X, whereby the stroke length of the plunger 11 is adjusted and the flow rate of the pump 1 is adjusted. ,
This kind of flow rate adjusting mechanism requires both a cam device composed of the plate cam 16 and a drive source such as a motor for rotating the plate cam 16 and a stop device X for adjusting the backward limit position of the plunger 11. There is a problem that the structure becomes complicated and the cost becomes high, and the screws, gears, and the like of the stop device X are backlashed, so that precise adjustment cannot be performed. In addition, the stop plate 24 of the stop device X
Since the movement of the pump is linear and the change of the retracted limit position of the plunger 11 is linear, the pump flow rate can be changed only linearly, and therefore, the precise adjustment of the flow rate can be performed near a specific set flow rate. It also has the disadvantage that it is impossible.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a flow rate adjusting mechanism for a plunger pump that has a simple structure and is capable of precisely adjusting the flow rate.

Means for Solving the Problems In order to achieve the above object, the mechanism of the present invention forms a passage for a transport liquid and a pumping cylinder in communication with the passage in the pump head, and the upstream side and the downstream side of the passage. A pair of check valves for controlling the transport liquid to flow from the upstream side to the downstream side of the passage, respectively, and further insert the front side of the plunger into the pumping cylinder in a liquid-tight manner. An urging mechanism for urging the plunger in the direction toward the base end thereof, a rotatably contact roller attached to the plunger, and a rotary plate cam disposed near the contact roller to rotate the rotary plate. By pressing the contact roller toward the tip of the plunger with the cam, the plunger is moved forward and the plunger is retracted by the urging force of the urging mechanism according to the rotation of the rotating plate cam. In the flow rate adjusting mechanism of the plunger pump which pumps the transport liquid by the reciprocating motion of the plunger, the contact roller is brought into contact with the rotary shaft of the rotary plate cam to stop and rotate the plunger backward. In accordance with the above, a fixed plate cam for continuously changing the retracted stop position of the plunger is rotatably attached, and a holding mechanism for holding the fixed plate cam at an arbitrary rotational position is arranged and held by the holding mechanism. The stroke length of the plunger is adjusted by changing the rotating state of the fixed plate cam and changing the contact position between the fixed plate cam and the contact roller along the plunger axial direction.

In this case, examples of the fixed plate cam that continuously changes the retracted stop position of the plunger as it rotates include disc-shaped, elliptical plate-shaped, and heart-shaped cams, but are not limited to these. Absent.

In the mechanism of the present invention, the fixed cam for determining the retracted limit position of the plunger is arranged coaxially with the rotary plate cam for reciprocating the plunger so as to be rotatable and capable of being held at a predetermined rotational position. Therefore, it is possible to move the contact point between the fixed cam and the roller at the base end of the plunger along the axial direction of the plunger by holding the fixed cam at the appropriate rotation position. Can be appropriately determined to adjust the pump flow rate. In this case, in the present invention, the fixed plate cam is formed in a shape in which the retracting stop position is continuously changed as the fixed plate cam is rotated, and a holding mechanism for holding the fixed plate cam at an arbitrary rotating position is provided. As a result, the contact position between the fixed plate cam and the contact roller can be continuously changed along the axial direction of the plunger, so that the stroke length of the plunger can be continuously adjusted to perform precise flow rate adjustment. .

Therefore, this mechanism has a simple structure and does not have a backlash of screws, gears, etc., unlike the conventional mechanism, so that the flow rate can be adjusted very precisely.

Next, the present invention will be described in detail with reference to examples.

Embodiment FIG. 1 and FIG. 2 show a flow rate adjusting mechanism of a plunger pump according to an embodiment of the present invention. In this case, in FIGS. 1 and 2, the same components as those of the device shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. In this device, the spring locking plate 13 does not extend downward as shown in FIG.

In the flow rate adjusting mechanism Y shown in FIGS. 1 and 2, 27
Is a fixed eccentric disc cam that can come into contact with the contact roller 15 rotatably attached to the rotary shaft 17 of the rotary eccentric disc cam 16. The fixed cam 27 has the same shape as the rotary cam 16. In this case, a bearing 29 is arranged in the rotary shaft insertion hole 28 of the fixed cam 27, and the rotary shaft 17 is rotatably supported in the bearing 29, whereby the rotary shaft insertion hole 28 is formed. The rotary shaft 17 can rotate therein. Further, a bolt 30 is fixed coaxially with the rotating shaft 17 on the side surface of the fixed cam 27- (a surface opposite to the surface facing the rotary cam 16), and fixed on the outer side of the fixed cam 27-side surface. Bolt through-hole 31 through which the bolt 30 can rotate so as to face the cam 27.
Is provided with a side plate 32. The tip of the bolt 30 projects through the bolt through hole of the side plate 32 to the outside of the side plate 32, and the nut 33 is screwed to the tip of the bolt 30 outside the side plate 32. As a result, by rotating the bolt 30, the fixed cam 2
7 can be rotated, and by fixing the nut 33 to the side plate 32 at the appropriate rotation position of the fixed cam 27, the fixed cam 27 can be held at the predetermined rotation position.

Therefore, when the pump flow rate is adjusted using the flow rate adjusting mechanism Y shown in FIGS. 1 and 2, the reciprocating motion of the plunger 11 is performed by the rotation of the rotary cam 16 as in the mechanism X shown in FIG. When adjusting the backward limit position of 11, the fixed cam 27 is rotated by turning the bolt 30 with the nut 33 being loosened, and the fixed cam 27 is held at an appropriate rotating position by tightening the nut 33. Is. That is, in the mechanism Y, when the plunger 11 retracts, the retraction stops when the roller 15 contacts the fixed cam 27. However, since the fixed cam 27 is eccentric, the fixed cam 27 is rotated. The portion of the fixed cam 27 that contacts the roller 15 is fixed to the plunger 11
Can be freely changed back and forth along the axial direction of
Therefore, by fixing the fixed cam 27 at the appropriate rotation position, the backward limit position of the plunger 11 can be set appropriately, and the stroke length of the plunger 11 can be set freely.

For example, as shown in FIG. 3, the fixed cam 27 is held so that the distance from the contact portion on the side of the fixed cam 27 with the contact roller 15 to the rotation center of the fixed cam 27 becomes the minimum radius a of the fixed cam 27. In this case, the pump flow rate will be maximum. When the fixed cam 27 is held so that the distance becomes the maximum radius b of the fixed cam 27 as shown in FIG. 4, the pump flow rate becomes zero (minimum flow rate). Then, as shown in FIG. 5, by setting the distance to various distances c between the minimum radius a and the maximum radius b, the pump flow rate can be appropriately set between the maximum flow rate and the minimum flow rate. .

That is, in FIGS. 3 and 5, (A) shows the forward limit position of the plunger 11, and (B) shows the backward limit position of the plunger 11. In the state shown in FIG. The stroke length L of 11 is a difference b−a = L between the maximum radius b of the rotating cam 16 and the minimum radius b of the fixed cam 27, and the stroke length L becomes maximum. Further, in the state shown in FIG. 4, the stroke length L becomes a difference bb = L between the maximum radius b of the rotating cam 16 and the maximum radius b of the fixed cam 27, and the stroke length becomes zero. Further, in the state shown in FIG. 5, the stroke length L is the maximum radius b of the rotating cam 16 and the contact roller 1 of the fixed cam 27.
Difference bc from the distance c from the point of contact with 5 to the center of rotation
= L, and the stroke length L can be appropriately set by setting c to various distances.

In the above embodiment, the rotary disk cam 16 and the fixed disk cam 27 having the same shape are arranged coaxially, but the shapes of both cams are not particularly limited. For example, by appropriately selecting the shape of the fixed cam, it is possible to expand the flow rate change near a specific set flow rate and perform precise adjustment. Further, the holding mechanism of the fixed cam and other configurations may be variously modified without departing from the gist of the present invention.

Effect of the Invention As described above, in the flow rate adjusting mechanism of the plunger pump according to the present invention, the rotary plate cam and the fixed plate cam are coaxially arranged, and the plunger stroke length is changed by changing the relative positions of both the plate cams. Since the mechanism is adjusted, the mechanism is simple, and since there is no backlash of screws, gears, etc. unlike the conventional device, precise flow rate adjustment is possible. In this case, since the fixed plate cam that continuously changes the retracted stop position of the plunger as it rotates is used, the stroke length of the plunger can be continuously adjusted. Further, by appropriately selecting the shape of the fixed cam, it is possible to expand only around a specific flow rate and perform more precise adjustment.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a state in which a flow rate adjusting mechanism according to an embodiment of the present invention is arranged in a plunger pump, and FIG.
The figure is a partially omitted plan view showing the flow rate adjusting mechanism of the same example,
FIG. 4, FIG. 4 and FIG. 5 are explanatory views showing a state in which the plunger is advanced and retracted by the flow rate adjusting mechanism of the present invention, and FIG. 6 is a partial sectional view showing a state in which the conventional flow rate adjusting mechanism is arranged in the plunger pump. It is a side view. DESCRIPTION OF SYMBOLS 1 ... Plunger pump, 2 ... Pump head, 3 ... Transport liquid passage, 4, 5 ... Check valve, 10 ... Pumping cylinder, 11 ... Plunger, 14 ... Spring, 15 ... Roller, 16 ... Rotating disk cam, 17 … Rotation axis, 27… Fixed plate cam

Claims (1)

[Scope of utility model registration request] 1. A passage for transporting liquid and a pumping cylinder communicating with the passage are formed in the pump head, and the transporting liquid flows from the upstream side to the downstream side of the passage on the upstream side and the downstream side of the passage. And a pair of check valves for controlling so that the plunger tip is liquid-tightly inserted into the pumping cylinder.
An urging mechanism for urging the plunger toward the base end side is arranged, a contact roller is rotatably attached to the plunger, and a rotary plate cam arranged near the contact roller is rotated to rotate the rotary plate cam. By pressing the contact roller toward the tip of the plunger with, the plunger is moved forward and the plunger is retracted by the urging force of the urging mechanism according to the rotation of the rotating plate cam, and the reciprocating motion of the plunger pumps the transport liquid. In the flow rate adjusting mechanism of the plunger pump, the fixed plate that continuously changes the retracted stop position of the plunger as the contact roller hits the rotary shaft of the rotary plate cam to stop the plunger from retracting and rotate. The cam is rotatably attached, and a holding mechanism for holding the fixed plate cam at an arbitrary turning position is provided. The stroke length of the plunger is adjusted by changing the rotating state of the fixed plate cam held by the holding mechanism to change the contact position between the fixed plate cam and the contact roller along the plunger axial direction. A feature of the plunger pump is the flow control mechanism.