JP3297143B2 - Non-pulsation metering pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulsation-free fixed-quantity discharge pump, and more particularly to a pulsation-free fixed-quantity discharge pump suitable for use in a liquid chromatograph or the like.

[0002]

2. Description of the Related Art A pump used for a liquid chromatograph or the like preferably has a non-pulsating discharge flow rate waveform. However, two pumps are used for mixing a reagent and a diluent. If used, the configuration would be large. Also, if a large volume of the mixed solution obtained by previously mixing the reagent and the diluting solution is put in a large tank and this mixed solution is used, it takes a long time to use up the large volume of the mixed solution. Therefore, there is a problem in terms of the life of the reagent, such as deterioration of the reagent in the mixture within a long time.

Meanwhile, the conventional non-pulsating fixed-quantity discharge pump has a structure in which a plurality of pumps having special discharge flow waveforms are combined to synthesize a mutual flow waveform to obtain a discharge flow waveform without pulsation.

[0004] For this reason, the two types of fluid at a fixed ratio,
Mixing without pulsation required two dual pumps. Further, it is necessary to provide a control device for each pump in order to control the discharge flow rate. In other words, to mix the two fluids at a constant ratio without pulsation, two control devices, two drive sources, and four pump units were required.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a non-pulsating fixed-quantity discharge pump which is small and can mix two kinds of fluids at a constant ratio without pulsation. In other words, an object of the present invention is to provide a non-pulsation-free fixed-quantity discharge pump including one drive source, one control unit, and three pump units.

[0006]

According to a first aspect of the present invention, there is provided a three-way reciprocating pump having a common rotation axis and a discharge port of a first and a second pump. , The suction and discharge phases of the first and second pumps are matched, the displacement directions of the first and second pumps are matched, and the first and second pumps are synchronized at an arbitrary phase. The sum of the discharge amounts of the pumps always keeps a specific value, the discharge amount of each pump can be changed by the axial displacement of the rotating shaft, the volume change of the pump chamber of the third pump, and the first and second pumps 3. The non-pulsating fixed-quantity discharge pump in which the discharge of the third pump compensates each other so that the discharge amount from the third pump always becomes a constant value in an arbitrary phase. The invention according to claim 2, wherein the first and second pumps Drive cam is mounted at an angle to the rotating shaft Eccentricity in the axis-perpendicular direction is changed by the sliding on the sliding shaft which, and is non-pulsating dispensing pump according to claim 1 in which the eccentric direction of both cam is characterized in that match.

[0007]

Embodiments of the present invention will be described below in detail.

As shown in FIG. 1, a non-pulsating fixed-rate discharge pump 1 according to an embodiment of the present invention has a first plunger pump 2 and a second plunger pump 3 on a suction side and a third plunger pump 3 on a discharge side.
And a plunger pump 4. The first reciprocating plunger 5 in the first plunger pump 2, the second reciprocating plunger 6 in the second plunger pump 3, and the third reciprocating plunger 7 in the third plunger pump 4 have their axes parallel to each other. The first plunger pump 2, the second plunger pump 3, and the third plunger pump 4 are arranged such that the third plunger pump 4 is sandwiched between the first plunger pump 2 and the second plunger pump 3.

The suction port of the first plunger pump 2 is
Is connected via a check valve 11 to a first pipe 10 through which a first fluid 9 flows from a first tank 8 containing the fluid. A discharge port of the first plunger pump 2 communicates with a suction port of the third plunger pump 4 via a check valve 11.
It is connected to the pipe 12. The suction port of the second plunger pump 3 is connected to a third pipe 15 for flowing the second fluid 13 from a second tank 14 containing the second fluid 13, and a check valve 11.
Are connected via The discharge port of the second plunger pump 3 is connected via a check valve 11 to a fourth pipe 16 communicating in the middle of the second pipe 12. The suction port of the third plunger pump 4 is connected to the second pipe 12 through a check valve 11.
And its discharge port is connected to the fifth pipe 17 via the check valve 11.

When the non-pulsating fixed-rate discharge pump 1 is used, for example, for supplying a reagent to a liquid chromatograph, for example, the first fluid 9 is a reagent, the second fluid 13 is a diluent, The five pipes 17 are connected to a liquid chromatograph.

The non-pulsating fixed-rate discharge pump 1 comprises the first
The first cam mechanism 18 abutting on the driving side terminal of the reciprocating plunger 5, the second cam mechanism 19 abutting on the driving side terminal of the second reciprocating plunger 6, and the third reciprocating plunger 7.
Via the third cam mechanism 20 that abuts on the drive side terminal section of
The first reciprocating plunger 5 and the second reciprocating plunger 6
And the rotating shaft 2 for reciprocatingly driving the third reciprocating plunger 7
1 is provided in a direction orthogonal to the axis of the first reciprocating plunger 5, the second reciprocating plunger 6, and the third reciprocating plunger 7.

The rotating shaft 21 is rotatable between bearings via a position adjusting mechanism 22 and the rotating shaft 21
Are supported so as to be movable along the axis of. One end of the rotating shaft 21 on the side opposite to the position adjusting mechanism 22 is connected to an output shaft 25 via a worm wheel 23 and a worm 24 slidably supported by the rotating shaft 21. In addition, 2
Reference numeral 6 denotes a bearing mounted on the worm wheel 23, and reference numeral 27 denotes a key inserted in a shaft hole of the worm hole 23.

The first reciprocating plunger 5 penetrates the pump chamber of the first plunger pump 2 via a seal 28, and the end of the first reciprocating plunger 5 outside the pump chamber is connected to the first cam mechanism 18. It is connected to the first drive rod 29 that abuts. The second reciprocating plunger 6 penetrates the pump chamber of the second plunger pump 3 via the seal portion 30, and the end of the second reciprocating plunger 6 outside the pump chamber contacts the second cam mechanism 19. It is connected to the rod 31. The third reciprocating plunger 7 penetrates through the pump chamber of the third plunger pump 4 via the seal portion 32, and the end of the third reciprocating plunger 7 outside the pump chamber contacts the third cam mechanism 20. It is connected to the rod 33.

The diameter of the first reciprocating plunger 5, the diameter of the second reciprocating plunger 6, and the diameter of the third reciprocating plunger 7 are designed to be substantially the same.

The position adjusting mechanism 22 has an adjusting screw shaft 34 connected to one end of the rotating shaft 21 via a joint via a dial 36 provided on a small diameter shaft 35 extending from the adjusting screw shaft 34. The rotation shaft 21 is configured to be able to move in the direction of the arrow in FIG. A cylindrical case is attached to the dial 36, and a scale is engraved on each of them. By rotating the dial 36, the moving amount of the rotary shaft 21 can be read or set by a combination of the scales. .

The third cam mechanism 20 is disposed so as to be sandwiched between the first cam mechanism 18 and the second cam mechanism 19.

The first cam mechanism 18 has a disk-shaped first cam member 38 having first eccentricity setting means 37, and the first cam member 38 is moved by the rotation shaft 21 to set the first eccentricity. The amplitude of the eccentricity in the radial direction from the axis of the rotating shaft 21 is varied via the means 37. Regardless of the fluctuation in the radial eccentricity amplitude, the movement of the first cam member 38 in the axial direction is restricted by an appropriate member (not shown).

The disc-shaped first cam member 38 and the end of the first drive rod 29 are connected by a spring back mechanism.
Press and contact in point or line contact. The reference numeral 39 denotes a first coil spring wound around the outer periphery of the first drive rod 29, and the reference numeral 40 denotes a bearing.

The first eccentricity setting means 37 is a disk-shaped first eccentricity setting means.
The first inclined cylindrical member 42 forming a part of the rotating shaft 21 is loosely inserted into a first insertion hole 41 provided at the center of the cam member 38.

Therefore, the rotating shaft 21 is connected to the position adjusting mechanism 2.
2, the first inclined cylindrical member 42 slides in the first insertion hole 41 in a direction orthogonal to the axial direction, whereby the disc-shaped first cam is moved. The member 38 rotates eccentrically with respect to the rotation shaft 21 while changing the eccentricity.

Here, the eccentricity of the disc-shaped first cam member 38 is determined by the position where the center Oa of the first cam member 38 matches the center Ob of the rotating shaft 21 and the position where the amplitude L reaches the maximum value _Lmax. However, since the cross-sectional shape (shape of the first cam member 38) of the disc-shaped first cam member 38 orthogonal to the rotation axis 21 is circular, the amplitude L at an arbitrary position is determined.
Is represented by the following equation.

L = L _max · cos θ (1) where θ indicates the rotation angle of the rotating shaft 21.

Accordingly, the discharge flow rate waveform q ₁ of the first plunger pump 2 operated by this is: q ₁ = Aε ₀ · sin θ (2) (where A is the cross-sectional area of the first reciprocating plunger,
ε is the amount of eccentricity, and θ is the cam rotation. ).

On the other hand, the second cam mechanism 19 has basically the same structure as the first cam mechanism 18 and includes a disk-shaped second cam member 44 having second eccentricity setting means 43. ,
The second cam member 44 is moved to the second
The amplitude of the eccentricity in the radial direction from the axis of the rotating shaft 21 is varied via the eccentricity setting means 43.

Regardless of the fluctuation of the amplitude of the eccentricity in the radial direction, the movement of the second cam member 44 in the axial direction is restricted by an appropriate member (not shown). The disc-shaped second cam member 44 and the end of the second drive rod 31 are pressed and contacted in a point or line contact manner by a springback mechanism. Incidentally, what is indicated by 45 is the second drive rod 3.
The first coil spring wound around 3
Reference numeral 6 denotes a bearing.

The second eccentricity setting means 43 is a disk-shaped second eccentricity setting means.
A second inclined cylindrical member 48 forming a part of the rotary shaft 21 is loosely inserted into a second insertion hole 47 provided at the center of the cam member 44. Therefore, when the rotating shaft 21 moves in the axial direction of the rotating shaft 21 via the position adjusting mechanism 22, the second inclined cylindrical member 48 slides in the second insertion hole 47 in a direction orthogonal to the axial direction, As a result, the disk-shaped second cam member 44 rotates eccentrically with respect to the rotating shaft 21 while changing the eccentricity.

However, the second cam mechanism 19 includes a plane parallel to the rotation axis and in contact with the circular cam portion.
By connecting the second reciprocating plunger to a mechanism movable in a direction perpendicular to the rotation axis, that is, a springback mechanism or an Oldham coupling mechanism, the displacement Δ of the second reciprocating plunger is changed.
x becomes Δx = εcos θ, and the second plunger pump 6
It is adjusted to the discharge flow waveform q ₂ to _{q 2 = A (ε 0 -ε} ) · sinθ ··· (3). In addition, what is indicated by 40 is a bearing.

The third cam mechanism 20 includes a pseudo-cylindrical third cam member 49, which is sandwiched between the first inclined column member 42 and the second inclined column member 48, and Supported by The first inclined columnar member 42
And the second inclined cylindrical member 48 have a symmetrical positional relationship about the third cam mechanism 20.

The contact between the pseudo-cylindrical third cam member 49 and the drive-side end of the third reciprocating plunger 7, that is, the outer end of the third drive rod 33, is performed by the spring-back mechanism. The drive rod 33 is pressed against and contacted in a line contact manner via a roller-shaped rotary body 50 interposed at the outer end of the drive rod 33. In addition, this contact mechanism may be a spherical rotating body instead of the roller-shaped rotating body 50 as described above, and may be changed from a line contact state to a point contact state. Alternatively, the outer end of the third drive rod 33 may be formed in a ball field, and the spherical outer end may be in a line contact state.

In the third cam mechanism 20, the relationship between the cam radius r of the pseudo columnar cam 49 and the rotation angle θ is determined by the distance between the center of rotation of the pseudo columnar cam 49 and the center of the roller-shaped rotary body 50 in FIG. When x is 0 ≦ θ ≦ π, x = Aε ₀ θ / π + A
ε ₀ cos θ + x ₀ and the center distance x is π <θ
When <2π, the output direction component r _x of the radius r of the cam 49 is set to 0 ≦ θ so that x = Aε ₀ θ / π + x ₀ −Aε _0.
When ≦ π, r _x = Aε ₀ θ / π + Aε ₀ cos θ + r
₀ , and when the center-to-center distance r _x is π <θ <2π,
r is determined so that r _x = Aε ₀ θ / π + x ₀ −Aε ₀ .

At this time, x ₀ is the minimum distance between the centers, and r ₀ is the minimum radius.

Thus, the output waveform v ₀ becomes v ₀ = dx / d
From θ, when 0 ≦ θ ≦ π, v ₀ = Aε ₀ (1 / π−s
in θ), and when π <θ <2π, v ₀ = Aε ₀
(1 / π), the suction discharge flow rate waveform q ₄
When 0 ≦ θ ≦ π, q ₄ = Aε ₀ (1 / π−sin θ) (4), and when π <θ <2π, q ₄ = Aε ₀ (1 / π) ( ₄ ) 5)

Next, the operation of the embodiment of the present invention will be described.

First, when the output shaft 25 is driven and rotated, the rotating shaft 21 is rotated via the worm wheel 23 and the worm 24.
Rotates. At this time, when the center Oa of the first cam member 38 coincides with the center Ob of the rotating shaft 21, the first reciprocating plunger 5 is not driven because the first cam member 38 has no eccentricity, and the first reciprocating plunger 5 is not driven. One plunger pump 2 does not operate.

At this time, since the second cam member 44 has the maximum eccentricity, the second reciprocating plunger 6 causes the second plunger pump 3 to have the maximum discharge amount.

Therefore, the dial 36 of the position adjusting mechanism 22
Is operated to move the rotary shaft 21 to, for example, the left side in the direction of the arrow shown in the figure, an eccentricity is given to the first cam member 38, whereby the first plunger pump 2 operates via the first reciprocating plunger 5. .

On the other hand, the eccentricity of the second cam member 44 is reduced, whereby the discharge amount of the second plunger pump 3 operated via the second reciprocating plunger 6 is reduced.

Further, the dial 36 of the position adjusting mechanism 22
When the rotation of the rotary shaft 21 is advanced to maximize the eccentricity of the first cam member 38, the center of the second cam member 44 coincides with the center of the rotary shaft 21, and the second cam member 44 has an eccentricity. As a result, the discharge flow rate of the first plunger pump 2 becomes maximum, and the operation of the second plunger pump 3 stops.

Further, since the first plunger pump 2 and the second plunger pump 3 are connected in parallel and have the same discharge phase, the combined waveform is the sum of the respective waveforms.

Then, the first plunger pump 2 at this time
Of the suction and discharge waveform q ₁ of the first cam member 38
₁ = Aε sin θ, as shown in FIG. 2, and the suction / discharge waveform q ₂ of the second plunger pump 3 is q ₂
= A (ε ₀ −ε) · sin θ, as shown in FIG. 3, and the flow rate waveform at the suction port of the third plunger pump 4 is 0 ≦ as a composite of the discharge waveforms of FIGS. 2 and 3.
When θ ≦ π, q ₃ = Aε ₀ · sin θ, and π <θ <
At 2π, both the first plunger pump and the second plunger pump are in the suction step, q ₃ = 0, and FIG.
The flow rate waveform shown in FIG.

On the other hand, the discharge waveform of the third plunger pump is q ₄ = Aε ₀ (1 / π−sin θ) when 0 ≦ θ ≦ π, and π <θ <, depending on the shape of the third cam member.
In the case of 2π, q ₄ is adjusted to Aε ₀ (1 / π).

Since the discharge ports of the first plunger pump 2 and the second plunger pump 3 and the suction port of the third plunger pump 4 are connected in series, the discharge flow rate waveform of the first plunger pump 2 and the second plunger pump 3 By synthesizing the combined flow waveform q ₃ with the discharge flow waveform of FIG. ₃ and the suction / discharge waveform of the third plunger pump 4, the discharge flow waveform q ₅ from the third plunger pump 3 is obtained as shown in FIG.
Becomes Aε ₀ (1 / π), and non-pulsating discharge is realized.

Table 1 shows the relationship between the cam rotation angle and the discharge flow rate waveform described in detail above.

[0044]

[Table 1]

As described above, according to the non-pulsating fixed-rate discharge pump of the present embodiment, the two liquids can be mixed and the mixed liquid can be discharged without pulsation, and the first reciprocating plunger 5 and the second 0 each by adjusting the stroke of the reciprocating plunger 6
Since the flow rate can be set to 100% to 100%, the mixing ratio of the two liquids can be set arbitrarily (0 to infinity). In addition, the amount of discharge from the third plunger pump 4 can be variously controlled by controlling the operating speed of the first reciprocating plunger 5, the second reciprocating plunger 6, and the third reciprocating plunger 7 by controlling the rotation speed of an inverter or the like of the drive motor. Can be set.

Further, since the already mixed two liquids are sent to the suction port of the third plunger pump 4, the premixing can be performed by the third reciprocating plunger 7.

There is also an advantage that the configuration can be made smaller than when a plurality of pumps are used as in the conventional example.

The present invention is not limited to the above embodiment, and the design can be appropriately changed within the scope of the present invention.

[0049]

According to the present invention described in detail above, since the above-described configuration is employed, the fluid is small and the two kinds of fluids are fixed at a constant ratio.
Also, it is possible to provide a pulsation-free fixed-quantity discharge pump capable of mixing without pulsation.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a non-pulsating fixed-rate discharge pump according to the present invention.

FIG. 2 is an explanatory diagram illustrating a flow rate waveform discharged from a first plunger pump.

FIG. 3 is an explanatory diagram showing a flow rate waveform discharged from a second plunger pump.

FIG. 4 is an explanatory diagram showing a combined flow waveform of a flow waveform discharged from a first plunger pump and a flow waveform discharged from a second plunger pump.

FIG. 5 is an explanatory diagram showing a combined flow waveform of a discharge flow waveform of a third plunger pump by a third cam member and a flow waveform sucked by the third plunger pump.

FIG. 6 is an explanatory diagram showing movements of a first cam, a second cam, and a third cam.

[Explanation of symbols]

 2 1st plunger pump 3 2nd plunger pump 4 3rd plunger pump 5 1st reciprocating plunger 6 2nd reciprocating plunger 7 3rd reciprocating plunger 18 1st cam mechanism 19 2nd cam mechanism 20 3rd cam mechanism 21 rotation axis

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI F04B 13/02

Claims (2)

(57) [Claims] 1. Three reciprocating pumps sharing a rotation axis are provided with discharge ports of first and second pumps and suction of a third pump.
Connected to the mouth , to match the suction and discharge phases of the first and second pumps, to match the displacement directions of the first and second pumps, and to discharge the first and second pumps at an arbitrary phase The total of always keeps a specific value, and the displacement of each pump can be changed by the axial displacement of the rotating shaft,
A non-pulsating fixed-rate discharge pump in which a change in the volume of the pump chamber of the third pump and the discharge of the first and second pumps compensate each other so that the discharge amount from the third pump always has a constant value in an arbitrary phase. 2. The drive cams of the first and second pumps change their eccentricity in the direction perpendicular to the axis by sliding on a slide shaft attached to the rotary shaft at an angle, and the eccentric directions of both cams coincide with each other. The pulsation-free fixed-quantity discharge pump according to claim 1, wherein: