JP2910842B2 - Lost motion device and metering pump using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to lost motion
Apparatus and metering pump using the same , and in particular, a small lost motion capable of producing a period during which the operation of the plunger is invalidated during the operation of the plunger
The invention relates to a device and a small metering pump provided with such a lost motion device .

[0002]

2. Description of the Related Art As a reciprocating metering pump used for precisely sending various kinds of chemicals and the like, for example, a cylinder provided with a diaphragm at one front end and a reciprocating fitting fitted to the cylinder are described. There is a diaphragm pump including a plunger having a cavity opened forward, and a pump chamber having an inflow valve and a discharge valve provided in front of the diaphragm.

In a diaphragm pump, hydraulic oil and the like are sealed in a space defined by a cavity of the plunger and the diaphragm in the cylinder.

[0004] When the plunger is retracted, the diaphragm also deforms rearward in accordance with the retraction of the plunger. As a result, the volume of the pump chamber is increased, so that the chemical solution is sucked into the pump chamber through an inflow valve provided in the pump chamber. On the other hand, when the plunger moves forward, the pressure of the pressure transmitting medium pressed by the plunger is applied to the diaphragm, so that the diaphragm is deformed forward. Thereby, the chemical solution in the pump chamber is pushed out through the discharge valve.

As a method of adjusting the discharge amount in the diaphragm pump, there are a method of changing the stroke of the plunger, and a method of changing the stroke of the plunger without changing the stroke of the plunger and moving the hydraulic oil halfway through the diaphragm when the plunger advances. The two methods using a mechanism called a so-called lost motion mechanism for preventing the hydraulic pressure from being applied are mainly used. Above all, the latter method has been often used because the mechanism of the plunger does not need to be changed and the mechanism can be simplified.

A conventional example of a variable flow rate diaphragm pump using a lost motion mechanism will be described below. FIG. 9 is a sectional view showing a longitudinal section of an example of a conventional variable flow rate diaphragm pump. In FIG. 9, the right side is the front.

In the variable flow rate diaphragm pump shown in FIG. 9, the plunger 1 has a cavity 1 opened forward.
One. In the vicinity of the rear end of the cavity 11, the cavity 11
A communication hole 12 is provided to communicate the outer circumference of the plunger 1 with the communication hole 12.

[0008] The plunger 1 is fitted to the cylinder 2 so that the open end of the cavity is forward and can reciprocate. A diaphragm 3 is attached to a front end of the cylinder 2.

A sleeve member 5 'is slidably fitted to the plunger 1. This sleeve-shaped member 5 '
The front and rear positions of the can be adjusted by a rack 5′a and a pinion 5′b provided on the outer periphery. The plunger 1 is provided with a sleeve-like member 5 '.
Reciprocate while sliding on The pinion 5'b is rotated by the knob 5'c. In FIG. 9, the plunger 1 is divided into two parts in a horizontal plane, and the upper half of the plunger 1
This shows a state in which the communication hole 12 is not closed by the sleeve-shaped member 5 ′, and the lower half of the plunger 1
Is closed by the sleeve-shaped member 5 ′.

[0010] The diaphragm 3 is fixed to the cylinder 2 by an end plate 42 of the diaphragm 3 can <br/> presser Rukoto. Further, the diaphragm 3 is pulled rearward by an urging means 31 having a coil spring as indicated by an arrow.

In front of the diaphragm 3, a pump chamber 4 is formed by the diaphragm 3 and an end plate 42.
The pump chamber 4 is provided with a suction valve 41a and a discharge valve 41b. Both the suction valve 41a and the discharge valve 41b are ball valves.

Incidentally, the cylinder 2 is fixed to the housing 8. The housing 8a, which is a part of the housing 8, is formed integrally with the cylinder 2. The casings 8 and 8a are formed in a liquid-tight manner, and contain hydraulic oil inside.

A crank arm 71 is attached to the end of the plunger 1 so as to be rotatable around a pin 72a. The other end of the crank arm 71 is attached to a flywheel 73 so as to be rotatable around a pin 72b. ing. A gear 74 is fixed to the flywheel 73, and the gear 74 meshes with a worm gear 75. When the worm gear 75 rotates, the gear 74 and the flywheel 73 rotate, and the plunger 1 reciprocates accordingly.

The operation of the lost motion mechanism in the variable flow rate diaphragm pump shown in FIG. 9 will be described below.

FIG. 10 is a schematic diagram showing how the lost motion mechanism in the variable flow rate diaphragm pump shown in FIG. 9 operates. In FIG.
(A) shows the state when the discharge amount is 0% of the total discharge amount,
(B) shows a state when the discharge amount is 50% of the total discharge amount, and (c) shows a state where the discharge amount is equal to the total discharge amount (100
%) Respectively. The length of the sleeve-shaped member 5 'is L + α. Here, L indicates the stroke length of the plunger 1, and α indicates the seal length required to close the through hole 12.

When the discharge amount is 0% of the total discharge amount, the sleeve-shaped member 5 'is fixed in the most advanced state, that is, the state in which the front end of the sleeve member 5' is in contact with the cylinder 2. In this state, when the plunger 1 is in the most retracted state, that is, at the bottom dead center, the through hole 12 is open. Therefore, the space formed by the cavity 11 inside the plunger 1, the inner wall of the cylinder 2, and the diaphragm not shown in FIG. 10 communicates with the outside of the plunger 1. Then, when the plunger 1 advances by the stroke length L and reaches the most advanced point, that is, the top dead center, the through hole 1
2 is closed.

Therefore, even if the plunger 1 moves forward, no pressure is applied to the diaphragm, so that the diaphragm is not deformed. Therefore, the discharge amount is 0%.

The sleeve-like member 5 'is moved from the above position by L
When the plunger 1 is fixed at the position retracted by 1/2, the communication hole 12 is open from the state where the plunger 1 is at the bottom dead center until the plunger 1 advances by the distance of L / 2. Therefore, no pressure is applied to the diaphragm. The communication hole 12 is closed from when the plunger 1 advances to a distance of L / 2 from the bottom dead center to when it reaches the top dead center.
Therefore, in this state, the pressure of the hydraulic oil is applied to the diaphragm, and the diaphragm is deformed.

Therefore, the amount of deformation of the diaphragm is 50% of the amount of deformation of the diaphragm in the total discharge amount of the variable flow rate diaphragm pump, and the discharge amount of the variable flow rate diaphragm pump is 50% of the total discharge amount. .

If the sleeve-shaped member 5 'is fixed at the most retracted position, that is, the position retracted by the stroke length L from the position where the discharge amount is 0%, the plunger 1
Is already closed at the bottom dead center, and the communication hole 12 is kept closed until the plunger 1 advances to the top dead center.

Therefore, the amount of deformation of the diaphragm becomes equal to the amount of deformation of the diaphragm at the entire discharge amount of the variable flow rate type diaphragm pump, so that the discharge amount of the variable flow rate type diaphragm pump becomes equal to 100% of the total discharge amount.

[0022]

However, in the conventional variable flow rate diaphragm pump, as described above, the sleeve-like member having the length of L + α can be moved over the plunger over the length L. I needed to. Therefore, compared with the case without the lost motion mechanism, the length of the plunger is longer than the length L + α of the sleeve-shaped member.
Only needed to be longer.

In the variable flow rate diaphragm pump, since the plunger and the sleeve-like member slide with each other, a gap seal is provided between these members.

As methods for suppressing leakage in the gap seal, there are generally a method of reducing the gap and a method of lengthening the sliding portion.

However, there is a limit in terms of cost to make the gap extremely small and constant. Therefore, in the conventional variable flow rate pump, a so-called long stroke in which the stroke length L is increased to lengthen the sliding portion. It has been common practice to make molds.

Therefore, the conventional variable flow rate diaphragm pump has a problem that the length of the plunger is inevitably increased, and the pump itself is also increased in size. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in a conventional variable flow rate diaphragm pump.

That is, an object of the present invention is to provide a lost motion device capable of shortening the entire length of a plunger and achieving an effective lost motion operation.

An object of the present invention is to provide a variable flow type diaphragm pump using a lost motion device or a lost motion mechanism which can make the variable flow type diaphragm pump smaller.

[0029]

Means for solving the above problems are as follows: (1) Fluid isolation for isolating a first fluid storage chamber for storing a fluid and a second fluid storage chamber for storing a fluid. A plunger that reciprocates in a through hole provided in the member in a liquid-tight manner, a driving unit that drives the plunger so that a tip end surface of the plunger reciprocates in the first fluid storage chamber, and a second part of the plunger. A communication hole provided in the plunger so that an opening provided in a peripheral side surface on the fluid storage chamber side communicates with the first fluid storage room, and a peripheral side surface of the plunger so that the opening can be closed. An opening closing member slidably formed, sliding range setting means capable of arbitrarily determining a sliding range of the opening closing member, and the plunger moving forward or backward toward the first fluid storage chamber. With the opening A pushing member for pushing the opening closing member;
Opening closing member biasing means for biasing toward the pressing member
A lost motion device which characterized by including bets, opening according to (2) wherein (1) has a circumferential groove for one round the peripheral side surface of the plunger, to (1) (3) The lost motion device according to (1) or (2), wherein the first fluid storage chamber according to (1) includes:
A pump chamber that exhibits a pump function by the fluid pressed by the plunger according to (1) is provided in parallel, and the second fluid storage chamber according to (1) is an oil storage tank that stores oil as a fluid. A metering pump characterized in that:

[0030]

FIG. 1 is a longitudinal sectional view showing a variable flow rate diaphragm pump which is an example of a metering pump of the present invention. In FIG. 1, the right side indicates the front, and the left side indicates the rear.

In FIG. 1, the plunger 1 is divided into upper and lower parts in a horizontal plane.
In the lower half, the plunger 1 is advanced most, and the opening closing member 5 is pushed by the step 13 provided in the plunger 1 in the lower half. Indicates a state in which

FIG. 2 is a perspective view showing the plunger, the opening closing member, and the sliding range setting means of the metering pump shown in FIG.

In the metering pump shown in FIGS. 1 and 2, the plunger 1 has a cavity 11 opened forward. The rear end of the cavity 11 is formed substantially flat. Then, at a position corresponding to the rear end portion of the cavity 11 on the peripheral side surface of the plunger, a circular shape is formed around the peripheral side surface once.
An opening 12 having a groove 12a having a rectangular cross section is formed, and a cavity 11 and the groove 12a are formed in the bottom of the groove 12a.
There are twelve holes 12b communicating with the bottom surface.
Each hole 12b is formed in a groove 1 from the center of the cavity 11.
A hole is radially drilled toward the bottom surface of 2a.

The plunger 1 is fitted in the internal cylindrical space of the cylinder 2 so that the open end of the cavity 11 faces forward and can reciprocate. Part of the internal cylindrical space of the cylinder 2 is a packing 21 so that hydraulic oil does not leak from between the plunger 1 and the internal cylindrical space of the cylinder 2. A plunger guide member 52 that guides the plunger 1 is fixed behind the cylinder 2. Plunger guide member 5
2 has a cylindrical space in which the plunger 1 can reciprocally fit on the inner surface thereof, and the center line of the cylindrical space coincides with the center line of the internal cylindrical space of the cylinder 2. It is fixed to. The plunger 1 is guided into the internal cylindrical space of the cylinder 2 by fitting into the cylindrical space of the plunger guide member 52.

The plunger 1 has an opening closing member 5.
Are slidably fitted. This opening closing member 5
Is movably attached to the outer periphery of the plunger 1 in a cylindrical shape. A flange 5A is formed at the rear end of the opening closing member 5, that is, at the rear end in the same direction as the rear end of the plunger 1. A coil spring 51 is inserted between the opening closing member 5 and the cylinder 2 as an opening closing member urging means. The opening closing member 5 is pushed rearward by the coil spring 51. A step 13 is provided at the rear end of the plunger 1.
Is provided so that the opening closing member 5 does not further recede from the position where the opening 12 is closed.

An outer sleeve 6 is provided outside the opening closing member 5. The outer sleeve 6 is a cylindrical body having an inner diameter larger than the diameter of the opening closing member 5 and the coil spring 51, and has a flange-shaped sleeve receiver extending toward the center of the cylinder at a rear end thereof. A member 61 is formed, and the opening receiving member 5 is prevented from retreating by the sleeve receiving member 61. The inner periphery of the sleeve receiving member 61 has a diameter larger than the diameter of the step 13 provided at the rear end of the plunger 1. The outer sleeve 6 is provided with two circular holes vertically. A guide rail 62 made of a round bar slidably penetrates this hole. A rack 6a is provided on the outer peripheral surface of the outer sleeve 6, and the rack 6a
Are engaged with the pinion 6b. The pinion 6b is rotated by the knob 6c. Therefore, when the knob 6c is turned, the pinion 6b also rotates accordingly, and as the pinion 6b rotates, the rack 6a moves and the outer sleeve 6 also moves back and forth. Thereby, the front-back position of the outer sleeve 6 is set.

A diaphragm 3 is attached to the front end of the cylinder 2 as a pressure receiving member. Diaphragm 3
Is fixed to the front of the cylinder 2 by an end plate 42. Here, the end plate 42 is a member attached to the front of the cylinder 2 and constituting a front end of the metering pump.
The diaphragm 3 is a thin plate formed by injection molding a thermoplastic elastomer. The diaphragm 3 is always pulled rearward by the urging means 31 having a coil spring.

In front of the diaphragm 3, a pump chamber 4 is formed by the diaphragm 3 and the end plate 42. The end plate 42 has a suction valve 41a and a discharge valve 41b.
Is attached. Intake valve 41a and discharge valve 41b
Are ball valves.

The cylinder 2 is fixed to the housing 8. A part 8 a of the housing 8 is formed integrally with the cylinder 2. The casings 8 and 8a are formed in a liquid-tight manner, and contain hydraulic oil therein so that the plunger 1 is completely below the oil level.

A crank arm 71 is attached to the end of the plunger 1 so as to be rotatable around a pin 72a. The other end of the crank arm 71 is attached to a flywheel 73 so as to be rotatable around a pin 72b. ing. A gear 74 is fixed to the flywheel 73, and the gear 74 meshes with a worm gear 75. The worm gear 75 is rotated by a motor (not shown). Worm gear 7
When the gear 5 rotates, the gear 74 and the flywheel 73 rotate, and accordingly, the plunger 1 reciprocates.

In this embodiment, the cylinder 2
The space formed by the front end face of the diaphragm and the diaphragm 3 and into which the working oil can flow in corresponds to the first fluid storage chamber for storing the fluid in the present invention, and the space in the housing 8 where the working oil is stored. That is, the oil storage tank corresponds to the second fluid storage chamber that stores the fluid in the present invention. The cylinder 2 separates the first fluid storage chamber and the second fluid storage chamber, and the cylinder 2
Since the inner cylindrical space of the cylinder 2 is a through hole, this cylinder 2
Corresponds to the fluid isolation member in the present invention. Also,
The crank arm 71, pins 72a and 72b, flywheel 7
3, the combination of the gear 74 and the worm gear 75
It corresponds to the driving means for driving the plunger in the present invention. In this embodiment, the opening 12 having the groove 12a is the opening in the present invention, and the cavity 11 and the hole 12b are the communicating holes in the present invention. The opening closing member 5 is the opening closing member in the present invention.
The combination of the outer sleeve 6, the sleeve receiving member 61, the guide rail 62, the rack 6a, the pinion 6b, and the knob 6c corresponds to a sliding range setting unit in the present invention. Step 13 provided at the rear end of plunger 1
Corresponds to a pushing member for pushing the opening closing member in the present invention. The pump chamber 4 formed by the diaphragm 3 and the end plate 42 corresponds to a pump chamber provided in the first fluid storage chamber in the present invention.

FIG. 3 shows how the discharge amount is changed in the metering pump shown in FIGS. 1 and 2.

In FIG. 3, (a) shows the state when the discharge amount is 0% of the total discharge amount, and (b) shows the state when the discharge amount is 50% of the total discharge amount.
And (c) shows the state when the discharge amount is equal to the total discharge amount (100%).

Here, L is the stroke length of the plunger 1, d is the length of the opening closing member 5, and α is the minimum seal length required to close the opening 12. In addition, FIG.
In the metering pump shown in FIG. 3, the length d of the opening closing member 5 is 0.4 L. The minimum seal length α is twice the width of the opening 12.

As shown in FIG. 3A, when the outer sleeve 6 is fixed at the most advanced position,
The opening closing member 5 attempts to retreat by the coil spring 51, that is, the urging force acts on the opening closing member 5 in the leftward direction in FIG. 3, but the plunger 1 moves to the most advanced position, that is, the top dead center. In some cases, the outer sleeve 6 is held by the flange-shaped sleeve receiving member 61 so that the opening 12 is located at the open position.

Therefore, since the opening 12 is always open, the cavity 11 inside the plunger 1
In communication with the outside of the Therefore, even if the plunger 1 reciprocates, the hydraulic pressure does not stand inside the cavity 11,
The diaphragm is not deformed, so that the discharge amount is zero.

Next, as shown in FIG. 3B, with the plunger 1 retracted to the bottom dead center, the outer sleeve 6
Is retracted by the length L / 2 from the above position, the opening closing member 5 receives the force of retreat from the coil spring 51 until the opening closing member 5 is held by the sleeve receiving member 61 of the outer sleeve 6. Both retreat.

At this time, when the plunger 1 is advanced from the bottom dead center, the opening 12 is open until the plunger 1 advances by the length L / 2. Therefore, since the cavity 11 inside the plunger 1 is in communication with the outside of the plunger 1, no hydraulic pressure is built up inside the cavity 11, and the diaphragm is not deformed.

When the plunger 1 continues to advance and advances by the length L / 2, the opening 12 is closed by the opening closing member 5. When the plunger 1 further moves forward and the rear end of the opening closing member 5 comes into contact with the step 13 of the plunger 1, the opening closing member 5 starts to move forward together with the plunger 1. At this time, the opening 12 is still closed by the opening closing member 5. Therefore, when the plunger 1 advances beyond the length L / 2, the hydraulic pressure starts to rise inside the cavity 11 as the plunger 1 advances. Therefore, when the plunger 1 reaches the top dead center, the hydraulic pressure corresponding to the length L / 2 stands inside the cavity 11. The amount of deformation of the diaphragm is proportional to the magnitude of the hydraulic pressure standing inside the cavity 11, and the amount of discharge of the metering pump is proportional to the amount of deformation of the diaphragm. Therefore, the discharge amount of the metering pump at this time is 50% of the total discharge amount.

As shown in FIG. 3C, when the plunger 1 is retracted to the bottom dead center, the outer sleeve 6 is moved to the most retracted position, that is, when the discharge amount is 0%.
Is retracted from the position to the position retracted by the stroke length L, the opening closing member 5 is retracted by the urging force of the coil spring 51 to the state held by the outer sleeve 6.

In this state, when the plunger 1 is at the bottom dead center, the communication hole 12 has already been completely closed by the opening closing member 5, and the plunger 1 has reached the top dead center and retreats. Until returning to the state, the opening 12 is kept closed by the opening closing member 5. here,
The minimum seal length α can be ignored in relation to the stroke length L of the plunger 1.

Therefore, the amount of deformation of the diaphragm is almost equal to the amount of deformation of the diaphragm at the entire discharge amount of the variable flow rate type diaphragm pump. Therefore, the discharge amount of the variable flow rate type diaphragm pump is almost equal to 100% of the total discharge amount. Become.

Although the embodiment of the metering pump of the present invention has been described above, the metering pump of the present invention is not limited to the above-described embodiment.

Hereinafter, each element of the metering pump of the present invention will be described in detail.

In the metering pump of the present invention, a part of the plunger is fitted reciprocally inside the cylinder. The plunger has at least one through hole communicating with a side surface of a portion of the plunger that does not fit the cylinder and a front end surface of the plunger, that is, a front end surface. Here, "the part of the plunger that does not fit with the cylinder"
Means a portion of the plunger exposed outside the cylinder even at the top dead center.

As an aspect of the communication hole in the plunger, for example, a forwardly opened cavity opened in the plunger communicates with an opening described later provided in a peripheral side surface of the plunger and the inside of the cavity. There is an embodiment having a hole to be formed.

As another mode of the communication hole, a blind hole formed vertically in the front end surface of the plunger, and an opening described later provided on the peripheral side surface of the plunger and the end of the blind hole communicate with each other. There is a communication hole having a hole. In such a communication hole, the number of blind holes formed in the front end face of the plunger may be one or two or more. 2 on the front end
When blind holes are formed, there is no particular limitation on the arrangement of blind holes.For example, these blind holes may be opened such that all blind holes are linearly opened on the front end face, or blind holes may be formed. A blind hole may be formed so that the holes are opened side by side on the circumference. There is no particular limitation on the number of holes perforated to the opening per one blind hole, but the number of holes is preferably about 1 to 5 per blind hole.

In the present invention, the opening means an opening provided on the peripheral side surface of the plunger, and has a shape such as a groove or a hole. And as mentioned above, these openings and the cavity or blind hole provided inside the plunger communicate with each other by the holes. Here, the peripheral side surface of the plunger refers to a side surface of the plunger having a substantially cylindrical shape.

One of the embodiments of the opening is shown in FIGS.
As in the opening in the embodiment shown in FIG. 3, there is a mode in which a circumferential groove is formed around the peripheral side surface of the plunger.
In the opening of this aspect, there is no particular limitation on the cross-sectional shape of the groove. Shapes are also possible. A hole communicating between the inside of this groove and the inner surface of a cavity provided inside the plunger or a blind hole formed inside the plunger is preferably open on the bottom surface of the groove, but the inside of the groove is preferably It is sufficient if the opening is provided somewhere, and it is not always necessary to open on the bottom surface of the groove.

The number of the holes is not particularly limited, and may be one or two or more. The number is preferably 3 to 20, and particularly preferably 6 to 12.

When two or more holes are provided,
It is preferable to pierce radially from the center of the cavity toward the inside of the groove.

The width of the opening is not particularly limited, but the opening is a dead zone.
However, it is not preferable that the width of the opening is too large. On the other hand, if the width of the opening is extremely small with respect to the stroke length L of the plunger, the passage resistance of the opening becomes too large, so that the opening is opened and the plunger front end face communicates with the outside of the plunger. In some cases, there is a problem that hydraulic pressure rises inside the cylinder and the diaphragm is deformed. A preferable range of the width of the opening is 1 to 10% of the stroke length L of the plunger.
A range of 1 to 5% is preferred.

The position of the opening on the side surface of the plunger is not particularly limited as long as it is a portion that does not fit into the cylinder, but from the front end of the plunger, the stroke length of the plunger and the opening closing member to be described later. It is preferable that the plunger is located at a position retracted from the front end of the plunger or is located behind the plunger by a length obtained by adding the minimum seal length.

However, it is preferable that the opening position of the opening does not retreat from the above-mentioned position if the length is equal to or greater than the sum of the minimum sealing length of the opening closing member and the length of the opening closing member. Here, the minimum seal length refers to a minimum length of the opening closing member required to seal the opening with a gap.

As another mode of the opening, there is a mode in which the communication hole is opened on the peripheral side surface of the plunger.

Also in this embodiment, the opening position of the opening on the side surface of the plunger is the same as in the above embodiment.
A position that is retracted from the front end of the plunger or is behind the position by a sum of a stroke length of the plunger and a minimum seal length of an opening closing member described later from the front end of the plunger. Is preferred.

However, it is preferable that the opening position of the opening does not retreat from the above-mentioned position if the length is equal to or more than the sum of the minimum sealing length of the opening closing member and the length of the opening closing member. Here, the minimum seal length refers to a minimum length of the opening closing member required to seal the opening with a gap.

In this embodiment, the number of openings is not particularly limited, and may be only one or two or more. The number is preferably 3 to 20, and particularly preferably 6 to 12.

In this embodiment, when two or more openings are provided, it is preferable that the openings are provided as openings of holes provided radially from the center of the cavity toward the side surface of the plunger.

Also in this embodiment, the diameter of the opening is not particularly limited. However, since the opening forms a dead zone, it is not preferable that the diameter of the opening is much larger than the stroke length L of the plunger. On the other hand, when the diameter of the opening is extremely small with respect to the stroke length L of the plunger, the passage resistance of the opening becomes too large, so that the opening is opened and the plunger front end face communicates with the outside of the plunger. In some cases, there is a problem that hydraulic pressure rises inside the cylinder and the diaphragm is deformed. The preferred range of the diameter of the opening is the stroke length L of the plunger.
Of 1 to 10%, and particularly preferably in the range of 1 to 5%.

The opening closing member has a length L obtained by adding the stroke length L of the plunger and the minimum seal length α.
It is preferable that the length be shorter than + α. This is because, even in the metering pump of the present invention, the plunger needs to be lengthened by the length d of the opening closing member as compared with the metering pump in which the lost motion device is not incorporated. If the length d of the opening closing member is longer than L + α, the object of the present invention cannot be achieved because the plunger needs to be further longer than in the case of the conventional variable flow rate metering pump.

On the other hand, the length of the opening closing member must be designed to be longer than the minimum seal length α. If the length of the opening closing member is shorter than the minimum seal length α, the through hole cannot be sealed.

The shape of the opening closing member is not particularly limited as long as the opening can be closed, but a cylindrical shape is preferable in terms of easy working.

The opening closing member is urged rearward or forward along the plunger by the opening closing member urging means. A pushing member for pushing the opening closing member will be described later, but when the pushing member is located behind the opening, the opening closing member urging means pushes the opening closing member backward. When the pushing member is located before the opening, the opening closing member biasing means is provided to bias the opening closing member forward. Is preferred.

As the means for urging the opening closing member, a spring is usually used. Examples of such a spring include a coil spring, a laminated rubber spring, a ring spring, and an air spring, and a coil spring is preferable. An opening closing member is preferably inserted into an internal space formed by the coil of the coil spring.

When the opening closing member is urged backward, a step or a projection is provided at the rear end of the opening closing member, and the rear end of the spring is locked to the step or the projection. Is preferred. On the other hand, when urging the opening closing member forward, it is preferable to provide a step or a projection at the front end of the opening closing member and lock the rear end of the spring to the step or the projection. Further, when the opening closing member is formed of metal and a coil spring or a ring spring is used as a spring, a rear end or a front end of the opening closing member and a rear end or a front end of the spring. May be fixed by brazing or welding. The other end of the spring can be locked to a member fixed in the metering pump of the present invention, for example, a cylinder or the like.

The plunger is provided with a pushing member for pushing the opening closing member. The position where the pushing member is provided may be behind or ahead of the opening portion opened on the side surface of the plunger. However, in the state where the opening closing member is in contact with the pushing member, the opening must be closed by the opening closing member, so that the pushing member is moved backward from the opening. When it is provided, it is preferable that the pushing member is not provided behind a position retracted by the length d of the opening closing member when viewed from the center of the opening. When the pushing member is provided in front of the opening, the pushing member is provided in front of a position advanced by the length d of the opening closing member as viewed from a rear edge of the opening. Preferably not.

The pushing member may be a step provided on the plunger surface. In addition, a projection provided on the plunger surface is also preferable.

In the above embodiment, the step 13 corresponds to the pushing member. The step 13 also has a function of restricting the opening closing member from retreating or moving forward on the plunger 1. ing.

The sliding range setting means is a means for setting a range in which the opening closing member slides on the plunger in cooperation with the pushing member, and various modes are possible. As an example among them, there is a mode in which the following external sleeve is provided.

The outer sleeve is a semi-fixed member provided outside the opening closing member, and has a function of holding the opening closing member so as not to retreat or advance. This member is configured to be able to adjust the front-rear position by any means. Therefore, once the position of the outer sleeve is determined, the opening closing member does not move backward or forward from the position locked by the outer sleeve. Thus, the position at which the opening closing member can be retracted or advanced at the maximum is determined by the position of the outer sleeve.

The outer sleeve may be, for example, a cylindrical member having an inner diameter larger than the outer diameter of the opening closing member, and the inner diameter of a part of the inner surface of the cylinder may be smaller than the opening closing member. There is an outer sleeve that is smaller than the outer diameter of the member.

Other examples of the outer sleeve include a flange, a piece extending toward the center at a rear end or a front end of a cylindrical member having an inner diameter larger than the outer diameter of the opening closing member. There is an external sleeve provided with a protruding or protruding member. In the outer sleeve, the flange-shaped, piece-shaped, or protruded member is a sleeve receiving member.

However, the shape of the outer sleeve is not limited to the shape described above, as long as the opening closing member can be held so as not to retreat or advance. As an outer sleeve having a shape other than the above-mentioned shape, for example, the outer sleeve has an outer diameter larger than the outer diameter of the opening closing member, and has an inner diameter larger than the outer diameter of the opening closing member that can pass through the plunger. There are rings and the like. However, this ring may have a certain thickness in the front-rear direction. Further, the inner circumference of the ring may be provided with a cut portion extending radially outward from the center direction, and may have a gear-like shape as a whole.

It is preferable that a guide rail is provided in parallel with the direction in which the plunger reciprocates, so that the outer sleeve can move along the guide rail. The number of guide rails is two in the embodiment shown in FIGS. 1 to 3, but is not limited to two, and may be one or three or more. Good.

In the metering pump of the present invention, a pressure receiving member, which is a member that is reversibly and elastically deformed in response to a change in pressure, is provided in front of the cylinder. Here, the front of the cylinder includes both the position of the front end of the cylinder and the position of the front of the cylinder.

As the pressure receiving member, a membrane member such as a diaphragm, a bag member such as a rubber bag, a tubular member such as a rubber tube,
A stretchable lantern-like member such as a bellows is used.

As the diaphragm, a diaphragm formed of an elastomer is preferable. In addition, a diaphragm formed of a thin metal plate and a diaphragm formed of a thin synthetic resin plate are also suitable.

When a diaphragm is used as the pressure receiving member, a pump chamber is further provided in front of the pressure receiving member. Here, the pump chamber is a space where the fluid to be sucked and discharged by the metering pump of the present invention is sucked and discharged, and usually includes a suction valve and a discharge valve.

When a rubber bag, a rubber tube, or a bellows is used as the pressure receiving member, a suction valve and a discharge valve may be provided directly on the pressure receiving member, and the pressure receiving member itself may be used as a pump chamber.

In the metering pump of the present invention, the space between the cylinder and the pressure receiving member is filled with a pressure transmitting medium. The pressure transmission medium is preferably a material whose volume hardly changes by pressurization. The pressure transmitting medium is preferably a material having a high boiling point to some extent and not solidifying at room temperature. Therefore, as the pressure transmission medium, water, hydraulic oil, mechanical oil, lubricating oil, glycerin, ethylene glycol, propylene glycol, low molecular weight polyethylene glycol, low molecular weight polypropylene glycol, and the like are preferable.

Hereinafter, another embodiment of the metering pump according to the present invention will be described.

FIG. 4 is a longitudinal sectional view showing an example of a variable flow rate type diaphragm pump in which a step as a pushing member is provided in front of the plunger. In FIG. 4, the right side indicates the front, and the left side indicates the rear.

In FIG. 4, the plunger 1 is divided into upper and lower parts in a horizontal plane, and the upper half shows a state in which the outer sleeve 6 provided outside the opening closing member 5 is most retracted, and the lower half shows the state described above. The state where the outer sleeve 6 is advanced most is shown.

FIG. 5 is a schematic diagram showing the principle of changing the discharge amount in the variable flow rate diaphragm pump shown in FIG.

In the variable flow rate diaphragm pump shown in FIG. 4, the plunger 1 has a cavity 11 opened forward, similarly to the variable flow rate diaphragm pump shown in FIG. The rear end of the cavity 11 is formed substantially flat. And the cavity 11 on the peripheral side of the plunger 1
An opening 12 having a groove 12a having a rectangular cross section is formed in a circular shape around the peripheral side surface at a position corresponding to the rear end portion.
Is formed, and twelve holes 12b communicating the cavity 11 and the bottom surface of the groove 12a are formed in the bottom surface of the groove 12a. Each hole 12b is formed radially from the center of the cavity 11 toward the bottom of the groove 12a.

The plunger 1 is fitted in the internal cylindrical space of the cylinder 2 so that the open end of the cavity 11 faces forward and can reciprocate. Part of the internal cylindrical space of the cylinder 2 is a packing 21 so that hydraulic oil does not leak from between the plunger 1 and the internal cylindrical space of the cylinder 2. A plunger guide member 52 that guides the plunger 1 is fixed behind the cylinder 2.

The plunger 1 has an opening closing member 5
Are slidably fitted. This opening closing member 5
Is movably attached to the outer periphery of the plunger 1 in a cylindrical shape.

Outside the opening closing member 5, there is a cylindrical body having an inner diameter larger than the diameter of the opening closing member 5 and a coil spring 51 described later, and a rear end thereof is directed toward the center of the cylinder. A flange-shaped sleeve receiving member 61 is formed to extend, and the opening closing member 5 is prevented from advancing by the sleeve receiving member 61. The inner circumference of the sleeve receiving member 61 has a diameter larger than the diameter of a portion of a step 13 described later provided on the plunger 1. The outer sleeve 6 is provided with two circular holes vertically. A guide rail 62 made of a round bar slidably penetrates this hole. A rack 6 a is provided on the outer peripheral surface of the outer sleeve 6.
a meshes with the pinion 6b. The pinion 6b is rotated by the knob 6c. Therefore, when the knob 6c is turned, the pinion 6b also rotates accordingly, and the rack 6a moves in accordance with the rotation of the pinion 6b, and the outer sleeve 6 also moves back and forth. Thereby, the front-back position of the outer sleeve 6 is set.

At the front end of the cylinder 2, a diaphragm 3 is attached as a pressure receiving member. Diaphragm 3
Is fixed to the front of the cylinder 2 by an end plate 42. Here, the end plate 42 is a member attached to the front of the cylinder 2 and constituting a front end of the metering pump.
The diaphragm 3 is always pulled rearward by the urging means 31 having a coil spring.

A pump chamber 4 is formed in front of the diaphragm 3 by the diaphragm 3 and an end plate 42. The end plate 42 has a suction valve 41a which is a ball valve.
And a discharge valve 41b.

Incidentally, the cylinder 2 is fixed to the housing 8. A part 8 a of the housing 8 is formed integrally with the cylinder 2. The casings 8 and 8a are formed in a liquid-tight manner, and contain hydraulic oil therein so that the plunger 1 is completely below the oil level.

The plunger 1 has a crank arm 71, a pin 7
It reciprocates by a combination of 2a and 72b, flywheel 73, gear 74, and worm gear 75.

However, in the variable flow rate diaphragm pump shown in FIG. 4, unlike the variable flow rate type diaphragm pump shown in FIG. 1, a push for pushing the opening closing member is provided in front of the plunger 1. A step 13 as a member is provided. A flange 5A is formed at the front end of the opening closing member 5. And the flange 5A
A coil spring 51 is inserted between the back of the plunger and the plunger guide member 52 as an opening closing member urging means.
The opening closing member 5 is pushed forward by the coil spring 51.

A flange-shaped sleeve receiving member 61 extending toward the center of the cylinder is formed at the front end of the outer sleeve 6 provided outside the opening closing member 5.
The opening closing member 5 is prevented from advancing by the sleeve receiving member. The sleeve receiving member 61 has an inner diameter larger than the diameter of the step 13 in the plunger 1.

In this embodiment, the cylinder 2
The space formed by the front end face of the diaphragm and the diaphragm 3 and into which the working oil can flow in corresponds to the first fluid storage chamber for storing the fluid in the present invention, and the space in the housing 8 where the working oil is stored. That is, the oil storage tank corresponds to the second fluid storage chamber that stores the fluid in the present invention. The cylinder 2 separates the first fluid storage chamber and the second fluid storage chamber, and the cylinder 2
Since the inner cylindrical space of the cylinder 2 is a through hole, this cylinder 2
Corresponds to the fluid isolation member in the present invention. Also,
The crank arm 71, pins 72a and 72b, flywheel 7
3, the combination of the gear 74 and the worm gear 75
It corresponds to the driving means for driving the plunger in the present invention. In this embodiment, the cavity 11 having the opening 12 is the communicating hole having the opening in the present invention. The opening closing member 5 is the opening closing member in the present invention. The outer sleeve 6 and the sleeve receiving member 6
1, a combination of the guide rail 62, the rack 6a, the pinion 6b, and the knob 6c corresponds to a sliding range setting unit in the present invention. The step 13 provided in front of the plunger 1 corresponds to a pushing member for pushing the opening closing member in the present invention. The diaphragm 3 and the end plate 42
The pump chamber 4 formed by (1) and (2) corresponds to the pump chamber provided along with the first fluid storage chamber in the present invention.

FIG. 5 shows how the discharge amount is changed in the metering pump shown in FIG.

In FIG. 5, (a) shows the state when the discharge amount is 0% of the total discharge amount, and (b) shows the state when the discharge amount is 50% of the total discharge amount.
And (c) shows the state when the discharge amount is equal to the total discharge amount (100%).

Here, L indicates the stroke length of the plunger 1, d indicates the length of the opening closing member 5, and α indicates the opening 1
2 shows the minimum seal length required to close 2. Note that d
Is L / 2. The minimum seal length α is twice the diameter of the opening 12.

As shown in FIG. 5A, when the outer sleeve 6 is fixed at the most retracted position,
The opening closing member 5 attempts to move forward by the coil spring 51, that is, the urging force acts on the opening closing member 5 in the rightward direction in FIG. 5, but the plunger 1 is at the most retracted position, that is, at the bottom dead center. In some cases, the outer sleeve 6 is held by the flange-shaped sleeve receiving member 61 so that the opening 12 is located at the open position.

Accordingly, since the opening 12 is always open, the cavity 11 inside the plunger 1
In communication with the outside of the Therefore, even if the plunger 1 reciprocates, the hydraulic pressure does not stand inside the cavity 11,
The diaphragm is not deformed, so that the discharge amount is zero.

Next, as shown in FIG. 5B, the outer sleeve 6 is advanced from the aforementioned position by a length L / 2.

At this time, when the plunger 1 is advanced from the bottom dead center, the opening closing member 5 moves forward together with the plunger 1 in a state of contact with the step 13 of the plunger 1 until the plunger 1 advances by the length L / 2. I do. Therefore, since the opening 12 is closed, the cavity inside the plunger 1 is in a state of being isolated from the outside of the plunger 1. Therefore, a hydraulic pressure rises inside the cavity 11, and the diaphragm is deformed. In this manner, when the plunger 1 reaches the position where the plunger 1 has advanced the length L / 2 from the bottom dead center toward the top dead center, the cavity 11
The hydraulic pressure of the sentence corresponding to the length L / 2 stands inside. Since the amount of deformation of the diaphragm is proportional to the magnitude of the hydraulic pressure standing inside the cavity 11, in this case, it is の of the amount of deformation when the flow rate is 100%.

When the plunger 1 advances from the bottom dead center toward the top dead center by a length L / 2, the flange 5A of the opening closing member 5 comes into contact with the sleeve receiving member 61 of the outer sleeve 6. Even if the plunger 1 is still advanced, the opening closing member 5 does not advance any further. Therefore,
The opening 12 is opened and the cavity 11 inside the plunger 1 is opened.
Are in communication with the outside of the plunger 1. Therefore, the hydraulic pressure standing inside the cavity 11 is released, and no hydraulic pressure is applied to the diaphragm. On the other hand, the diaphragm is the urging means 31
As a result, the diaphragm returns to the state before the deformation. Since the discharge amount of the diaphragm pump is proportional to the deformation amount of the diaphragm, the discharge amount of the metering pump at this time is 50% of the total discharge amount.

As shown in FIG. 3C, when the outer sleeve 6 is advanced from the most advanced position, that is, the position of the outer sleeve 6 when the discharge amount is 0%, to the position advanced by the stroke length L. The opening closing member 5 is advanced by the urging force of the coil spring 51 until it contacts the step 13 of the plunger 1.

In this state, the plunger 1 reciprocates with the communication hole 12 completely closed by the opening closing member 5. Here, the minimum seal length α can be ignored in relation to the stroke length L of the plunger 1.

Therefore, the amount of deformation of the diaphragm becomes almost equal to the amount of deformation of the diaphragm at the entire discharge amount of the variable flow rate type diaphragm pump. Therefore, the discharge amount of the variable flow rate type diaphragm pump is almost equal to 100% of the total discharge amount. Become.

FIG. 6 is a longitudinal sectional view showing an example of an embodiment in which a ring is used as an outer sleeve in the metering pump of the present invention. In FIG. 6, the right side shows the front, and the left side shows the rear.

FIG. 7 is a perspective view showing the plunger, the opening closing member, and the outer sleeve of the metering pump shown in FIG.

In the metering pump shown in FIG. 6, as in the metering pump shown in FIG. 1 and FIG.
Has a cavity 11 opened forward. The rear end of the cavity 11 is formed in a substantially planar shape, and an opening 12 communicating with the cavity 11 is provided near the rear end of the plunger 1.
Two are established. The arrangement of each opening 12 is also
This is the same as the arrangement of the openings 12 in the metering pump shown in FIG.

The plunger 1 is fitted to the cylinder 2 so that the open end of the cavity 11 faces forward and can reciprocate.

The point that the diaphragm is used as the pressure receiving member 3 is also the same as described in the metering pump shown in FIGS.

Further, the mechanism for reciprocating the plunger 1 is as described in the metering pump shown in FIGS.

However, in this metering pump, a ring is used as the outer sleeve 6.

As shown in FIGS. 6 and 7, the outer sleeve 6, which is a ring, has a certain thickness. The inner diameter of the ring is smaller than the outer diameter of the opening closing member 5 and the step 13 provided on the plunger 1
Is larger than the diameter of the part. Therefore, plunger 1
Can dive under the outer sleeve 6, but the opening closing member is prevented from retreating by the outer sleeve 6.

A hole 63 is formed in the outer sleeve 6, and a rod-shaped guide rail 62 passes through the hole 63. The outer sleeve 6 can slide on the guide rail 62. The outer sleeve 6 is a rack 6
a, the pinion 6b, and the knob 6c can change the front-back position.

FIG. 8 is a sectional view cut in the front-rear direction showing an example of an embodiment in which a rubber tube is used as a pressure receiving member in the metering pump of the present invention. In FIG. 8, the right side indicates the front, and the left side indicates the rear.

In the metering pump shown in FIG. 8, as in the metering pump shown in FIG. 1 and FIG.
Has a cavity 11 opened forward. The rear end of the cavity 11 is formed in a substantially planar shape, and 12 openings 12 are opened near the rear end of the cavity 11. The arrangement of the openings 12 is the same as the arrangement of the openings 12 in the metering pump shown in FIG.

The plunger 1 is fitted to the cylinder 2 so that the open end of the cavity 11 faces forward and can reciprocate.

The construction and operation of the opening closing member 5 and the outer sleeve 6 are also as described in the metering pump shown in FIG.

Further, the mechanism for reciprocating the plunger 1 is the same as that described in the metering pump shown in FIGS.

However, in the metering pump shown in FIG. 8, unlike the metering pump shown in FIGS. 1 and 2, a rubber tube 3 is attached instead of the diaphragm 3 as a pressure receiving member. The rubber tube 3 is attached to an end plate 42, and the end plate 42 is fixed to the front end of the cylinder 2. A suction valve 41 is provided at the inlet and the outlet of the rubber tube 3 respectively.
a and a discharge valve 41 b are provided, and the inside of the rubber tube 3 is a pump chamber 4.

In the metering pump shown in FIG. 8, when the plunger 1 retreats, the space formed by the cylinder 2 and the end plate 42 is reduced in pressure. Therefore, the rubber tube 3 expands, and the fluid to be conveyed is sucked into the rubber tube 3 through the suction valve 41a. On the other hand, when the plunger 1 moves forward, the space formed by the cylinder 2 and the end plate 42 is pressurized, and the rubber tube 3 contracts. Therefore, the fluid to be conveyed is discharged from the rubber tube 3 through the discharge valve 41b.

[0134]

According to the metering pump of the present invention, the sum of the length d of the opening closing member and the minimum seal length α is smaller than that of the plunger in the metering pump without the lost motion mechanism or the lost motion device. Length d + α
Only the plunger should be long. The length d of the opening closing member is shorter than the stroke length L of the plunger. Therefore, since the plunger can be shortened as compared with the conventional variable flow rate metering pump, the entire metering pump can be reduced in size.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a metering pump according to the present invention.

FIG. 2 shows a plunger of the pump shown in FIG. 1;
It is a perspective view which shows an opening part closing member and a sleeve.

FIG. 3 is a schematic explanatory view illustrating the principle of changing the discharge amount in the metering pump shown in FIGS. 1 and 2.

FIG. 4 is a longitudinal sectional view showing an example of a constant flow pump which is a variable flow rate type diaphragm pump in a mode in which a step which is a pushing member is provided in front of a plunger.

FIG. 5 is a schematic explanatory view illustrating a principle of changing a discharge amount in the metering pump shown in FIG.

FIG. 6 is a cross-sectional view cut in the front-rear direction showing an example of an embodiment using a ring as an outer sleeve in the metering pump of the present invention.

FIG. 7 is a perspective view showing a plunger, an opening closing member, and an outer sleeve in the metering pump shown in FIG. 6;

FIG. 8 is a cross-sectional view cut in the front-rear direction showing an example of an embodiment in which a rubber tube is used as a pressure receiving member in the metering pump of the present invention.

FIG. 9 is a sectional view showing a longitudinal section of an example of a conventional variable flow rate diaphragm pump.

FIG. 10 is a schematic view showing how a lost motion mechanism in the variable flow rate diaphragm pump shown in FIG. 9 operates.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Plunger 1, 11 ... Cavity, 12 ... Opening, 12a ... Groove, 12b ... Hole, 5 ... Opening closing member, 51 ... Coil spring, 13 ... ·Step,
6 ... external sleeve, 61 ... sleeve receiving member,
62: guide rails 62, 6a: rack, 6b
... Pinion, 6c ... Knob, 3 ... Pressure receiving member, 42 ... End plate, 2 ... Cylinder, 21 ... Packing, 31 ... Biasing means, 4 ... Pump Room, 41
a ... suction valve, 41b ... discharge valve, 8 ... housing,
8a: a part of the housing 8, 71: crank arm, 7
2a, 72b: pin, 73: flywheel, 74 ...
・ Gear, 75 ... worm gear

Claims (3)

(57) [Claims] 1. A plunger which reciprocates in a liquid-tight manner in a through hole provided in a fluid isolation member which is isolated from a first fluid storage chamber for storing a fluid and a second fluid storage chamber for storing the fluid, and the plunger. A driving means for driving the plunger such that a tip end surface of the plunger reciprocates in the first fluid storage chamber, and an opening provided on a peripheral side surface of the plunger on the side of the second fluid storage chamber. A communication hole provided in the plunger so as to communicate with the opening, an opening closing member slidably formed on a peripheral side surface of the plunger so as to close the opening, and sliding of the opening closing member. A sliding range setting means capable of arbitrarily determining a moving range; a pushing member for pushing the opening closing member as the plunger advances or retreats toward the first fluid storage chamber; and the opening. Closed
An opening closing member for urging a member toward the pushing member
Lost motion device, characterized by comprising a biasing means. 2. The opening according to claim 1, wherein the opening has a circumferential groove surrounding the peripheral side surface of the plunger.
A lost motion device according to item 1. 3. A pump provided with the lost motion device according to claim 1 or 2, wherein the first fluid storage chamber according to claim 1 is pumped by a fluid pressed by the plunger according to claim 1. 2. The metering pump according to claim 1, wherein a pump chamber that exhibits a function is provided, and the second fluid storage chamber according to claim 1 is an oil storage tank that stores oil as a fluid.