阅读说明：本技术 具有用于转子轴向位移的凸轮机构的微型泵 (Micropump having a cam mechanism for axial displacement of the rotor ) 是由 德里克·勃兰特 托马斯·怀斯 瑞加纳·马博特 阿德里安·布希 亚历山大·佩里尔 于 2018-12-03 设计创作，主要内容包括：一种微型泵,其包括：定子(4)；转子(6),其至少部分能够滑动且能够旋转地安装在该定子中；第一阀门(V1),其由第一阀门密封件(18)结合转子上的第一通道(42)而形成,第一阀门密封件围绕第一轴向延伸部安装在定子上；第二阀门(V2),其由第二阀门密封件(20)结合转子中的第二通道(44)而形成,第二阀门密封件围绕第二轴向延伸部安装在定子上；泵室(8),其形成于转子和定子之间以及第一阀门密封件和第二阀门密封件之间,以及凸轮系统,其包括位于转子或定子中的一个上的凸轮轨道(22,22’)和位于转子或定子中的另一个上的凸轮从动件(36,36’)。(A micropump, comprising: a stator (4); a rotor (6) at least partially slidably and rotatably mounted in the stator; a first valve (V1) formed by a first valve seal (18) mounted on the stator about the first axial extension in conjunction with a first passage (42) on the rotor; a second valve (V2) formed by a second valve seal (20) in combination with a second passage (44) in the rotor, the second valve seal being mounted on the stator about the second axial extension; a pump chamber (8) formed between the rotor and the stator and between the first and second valve seals, and a cam system comprising a cam track (22, 22 ') on one of the rotor or the stator and a cam follower (36, 36') on the other of the rotor or the stator.)

1. A micropump, comprising:

-a stator (4),

-a rotor (6) at least partially slidably and rotatably mounted in the stator, the rotor comprising a first axial extension (24) having a first diameter (D1) and a second axial extension (26) having a second diameter (D2), the second diameter being larger than the first diameter,

-a first valve (V1) formed by a first valve seal (18) mounted on the stator about the first axial extension in combination with a first passage (42) on the rotor configured to allow fluid communication past the first valve seal when the first valve is in an open position,

-a second valve (V2) formed by a second valve seal (20) mounted on the stator about the second axial extension in combination with a second channel (44) in the rotor configured to allow fluid communication past the second valve seal when the second valve is in an open position,

-a pump chamber (8) formed between the rotor and the stator and between the first valve seal and the second valve seal, and

-a cam system comprising a cam track (22, 22 ') on one of the rotor or the stator and a cam follower (36, 36') on the other of the rotor or the stator for axially displacing the rotor relative to the stator in dependence on rotation of the rotor, the cam track comprising a valve-closing full chamber area (28), a valve-closing chamber area (30), an intake area (32) and an exhaust area (34),

characterized in that the cam system comprises at least two cam tracks (22, 22 ') and associated cam followers (36, 36'), including a radially outward cam track (22) and associated radially outward cam follower (36), and a radially inward cam track (22 ') and associated radially inward cam follower (36'), the radially outward cam track and the radially inward cam track defining the same cam profile that expands over 360 degrees.

2. The micropump of claim 1 wherein said cam system includes two cam tracks, said radially outward cam track and said radially inward cam track being diametrically opposed to each other.

3. Micropump according to claim 1 or 2, wherein said discharge zone comprises a discharge holding position (34b) defining an intermediate axial position between the valve-closing full chamber zone and the valve-closing chamber zone to partially deliver the pumping cycle volume during the discharge phase.

4. A micropump according to claim 3, wherein said discharge retention position (34b) comprises a platform substantially perpendicular to the rotation axis (a) of said rotor (6).

5. The micropump of claim 4, wherein the platform of said discharge holding location (34b) extends over an angular arc of at least 15 degrees.

6. The micropump of claim 5, wherein the platform of said discharge holding location (34b) extends over an angular arc of at least 20 degrees.

7. The micropump of claim 1, wherein said cam follower comprises a chamfered nose corner (38a, 38 b).

8. The micropump of claim 1, wherein said exhaust region includes an exhaust ramp portion (34a), said exhaust ramp portion (34a) being inclined at an angle (β) of less than 45 degrees with respect to said valve-closing full chamber region (28) and said valve-closing chamber region (30).

9. The micropump of claim 1, wherein said discharge zone comprises one or two discharge holding locations (34b) at an axial position, said discharge holding locations (34b) being configured to divide said discharge zone into subunits substantially equal to the total axial displacement between a full pump chamber position and an empty pump chamber position.

10. The micropump of claim 1, wherein the pump module is coupled with a rotary drive comprising a stepper motor having a step position allowing the rotor to be stopped and held at a discharge holding position intermediate the valve-closed full chamber region (28) and the valve-closed cavity chamber region (30), the discharge holding position corresponding to an integer multiple of the step position.

11. Micropump according to claim 1, wherein said cam track is mounted on a head (10) of said rotor and said cam follower is mounted on said stator.

Technical Field

The present invention relates to a micropump. The micropump may be used for dispensing small quantities of fluid, in particular for medical applications, for example in drug delivery devices. The micropump in connection with the present invention may also be used in non-medical applications requiring high precision in the delivery of small amounts of fluids.

Background

In EP1803934 and EP1677859, a micropump for delivering small quantities of fluid is described, which micropump can be used in particular in medical and non-medical applications. The micropump described in the aforementioned document comprises a rotor having first and second axial extensions of different diameters, which engage with first and second seals of the stator to form first and second valves that open and close fluid communication across the respective seals as a function of the angular and axial displacements of the rotor. A pump chamber is formed between the first and second seals of the stator, whereby the volume of fluid pumped per revolution of the rotor is a function of the difference in diameter between the first and second rotor axial extensions and the axial displacement of the rotor, which is achieved by the cam system as a function of the angular position of the rotor relative to the stator. The ability to control the pumped volume per cycle as a function of the rotational and axial displacements of the rotor and the diameter difference between the rotational extensions enables very small amounts of fluid to be pumped per revolution of the rotor with high accuracy. The minimum volume delivered by the above-mentioned micropump corresponds to the maximum filling volume of the pumping chamber.

Although very small quantities can be pumped accurately with the known pumps described above, in certain applications the ability to dispense even smaller quantities of fluid in a well controlled manner would be beneficial.

The configuration of the cam system of the aforementioned known pumps may cause a slight inclination of the rotor, which may affect the wear and precision of the pump and cause undesired vibrations.

Disclosure of Invention

In view of the foregoing, it is an object of the present invention to provide a micro-pump that is capable of dispensing very small amounts of fluid in an accurate, reliable and safe manner.

Advantageously, a micropump is provided which is robust and very stable during operation.

Advantageously, a micropump is provided that is economical to manufacture.

Advantageously, a very compact micro-pump is provided.

It would be advantageous to provide a micro-pump that may have low cost disposable components and reusable components that are easy to couple and use.

Disclosed herein is a micropump comprising:

-a stator,

a rotor at least partially slidably and rotatably mounted in the stator, the rotor comprising a first axial extension having a first diameter and a second axial extension having a second diameter, the second diameter being larger than the first diameter,

a first valve formed by a first valve seal mounted on the stator about the first axial extension in combination with a first channel in the rotor configured to allow fluid communication past the first valve seal when the first valve is in an open position,

-a second valve formed by a second valve seal (20) mounted on the stator about the second axial extension in combination with a second channel in the rotor configured to allow fluid communication past the second valve seal when the second valve is in the open position,

-pump chambers formed between the rotor and the stator and between the first valve seal and the second valve seal, and

a cam system comprising a cam track on one of the rotor or stator and a cam follower on the other of the rotor or stator for axially displacing the rotor relative to the stator in accordance with rotation of the rotor. The cam track includes a valve-closed full chamber area, a valve-closed chamber area, an intake area, and a discharge area.

According to a first aspect of the invention, the discharge zone comprises a discharge holding position defining an intermediate axial position between the valve-closing full chamber zone and the valve-closing chamber zone to partially deliver the pumping cycle volume during the discharge phase.

According to a second aspect of the invention, the cam system comprises a radially outer cam track and an associated radially outer cam follower, and a radially inner cam track and an associated radially inner cam follower, the radially outer cam track and the radially inner cam follower being diametrically opposed to each other and defining the same cam profile that develops over 360 degrees. Advantageously, diametrically opposed cam tracks reduce the tilting moment on the rotor.

In an advantageous embodiment, the ejection holding position comprises a platform (plateau) substantially perpendicular to the rotation axis of the rotor.

In an advantageous embodiment, the platform of the ejection holding position extends over an angular arc of at least 15 degrees, preferably over an angular arc of at least 20 degrees.

In an advantageous embodiment, the cam follower comprises a chamfered nose corner.

In an advantageous embodiment, the discharge portion comprises a discharge ramp portion which is inclined at an angle (β) of less than 45 degrees with respect to the valve closure full chamber region and the chamber region.

In an advantageous embodiment, the discharge zone comprises one or two discharge holding positions at axial positions configured to divide the discharge zone into sub-units substantially equal to the total axial displacement between the full pump chamber position and the empty pump chamber position.

In an embodiment, the pump module is coupled to a rotary drive comprising a stepper motor having a step position that allows the rotor to be stopped and held at a discharge holding position intermediate the valve-closed full chamber region and the valve-closed cavity chamber region, the discharge holding position corresponding to an integer multiple of the step position.

In an advantageous embodiment, the cam track is mounted on the head of the rotor and the cam follower is mounted on the stator.

Other objects and advantageous features of the invention will become apparent from the claims, the detailed description and the accompanying drawings, in which:

drawings

FIG. 1 is a cross-sectional view of a pump module (shown without a motor drive and without a fluid source and fluid outlet fitting) according to an embodiment of the present invention;

fig. 2a and 2b are side views from opposite sides of the pump module of fig. 1 in the full pump chamber position.

FIGS. 3a and 3b are side views from opposite sides of the pump module of FIG. 1 in an intermediate fluid discharge position;

FIG. 4a is a perspective view of the pump module of FIG. 1 showing the rotor disassembled from the stator;

FIG. 4b is a perspective view of the rotor of the pump module of FIG. 4 a;

FIG. 4c is a perspective view of the stator of the pump module of FIG. 4 a;

FIG. 5 is a schematic illustration of a deployed cam track of a cam system for axially displacing a rotor relative to a stator of a micro-pump in accordance with an embodiment of the present invention;

FIGS. 6a and 6b are schematic illustrations of a deployed cam track profile of a cam system for axially displacing a rotor relative to a stator of a micro-pump according to another embodiment of the present invention;

FIG. 7 is a schematic illustration of a deployed cam track profile of a cam system for axially displacing a rotor relative to a stator of a micro-pump according to yet another embodiment of the present invention;

fig. 8 is a view illustrating a micro pump according to an embodiment of the present invention.

Detailed Description

With reference to the figures, the micropump 1 comprises a pump module 2, the pump module 2 comprising a stator 4 and a rotor 6, the rotor 6 being driven by a rotary drive 3, the rotary drive 3 comprising an electric motor 5, the electric motor 5 imparting a rotary motion on the rotor about an axis of rotation a. The rotor 6 is axially biased, for example by a spring 9, such that the cam system (which includes a cam track 46 on the rotor, the cam track 46 engaging a complementary cam follower 48 on the stator) imparts an axial displacement Ax to the rotor relative to the stator in dependence on a change in its angular position as the rotor rotates. Axial and rotational displacement of the rotor relative to the stator causes the first and second valves V1 and V2 (described in more detail below) to open and close to effect a pumping action. This general functional principle is known per se and is described, for example, in EP 1803934.

In an embodiment, the rotary drive 3 may be in the form of a reusable component for coupling to the pump module 2, and the pump module 2 may be in the form of a single-use disposable component. For example, in drug delivery applications, the pump module may be integrated into a single-use disposable component containing the fluid drug and the fluid output port (e.g., a needle or catheter tube), and the rotary drive may be integrated into a reusable component containing the power source, control electronics, and user interface, so that the reusable component may be coupled to the disposable component and then removed and re-coupled to a new disposable component after use of the disposable component.

In an embodiment, the pump inlet 14 may be formed at the shaft end of the rotor, while the outlet 16 may be disposed towards the end of the rotor comprising the cam. The outlet 16 may extend radially through the stator. The inlet and outlet ports may be reversed depending on the direction of rotation of the rotor relative to the stator and the valve seal configuration. Furthermore, in some embodiments, the pump may also be configured to be bi-directional, whereby the direction of fluid flow is dependent on the direction of rotation of the rotor. The inlet or outlet formed at the shaft end of the rotor may also be directed radially through the stator, rather than axially from the end of the stator. The skilled person will appreciate that various fluid passages for the inlet and outlet may be configured as required for connection to the fluid source and the fluid delivery location without departing from the scope of the invention.

The rotor 6 has a first extension 24 with a first diameter D1 and a second extension 26 with a second diameter D2, the first and second diameters having different values. In the illustrated embodiment, diameter D2 of second extension 26 is greater than diameter D1 of first extension 24. The difference between the first and second diameters associated with the axial displacement Ax of the rotor defines the pumping volume per rotor revolution.

The micro-pump includes a first valve V1 formed between the first extension of the rotor and the stator and a second valve V2 formed between the second extension of the rotor and the stator. The first valve V1 and the second valve V2 control the opening and closing of the respective inlet 14 or outlet 16.

The first valve V1 is formed by a first valve seal 18 mounted on the stator and a first channel 42 mounted on the rotor, the first channel 42 being configured to allow fluid communication past the first valve seal when the first valve seal is in an open position and not allow fluid communication past the first valve seal when the first valve V2 is in a closed position. The second valve V2 is formed by a second valve seal 20 on the stator 4 and a second passage 44 formed on the rotor 6, the second passage 44 allowing fluid communication across the second valve seal when the second valve V2 is in the open position and not allowing fluid communication across the second valve seal when the second valve V2 is in the closed position. Between the rotor 6 and the stator 4 and between the first valve seal 18 and the second valve seal 20, a pump chamber 8 is formed.

The pump chamber seal 21 circumferentially defines (circumscript) a second extension 26 and separates the pump chamber 8 from the pump external environment.

In the illustrated embodiment, the fluid passages 42, 44 are shown as axially extending grooves in their respective first and second rotor extensions 24, 26. However, in variations, other fluid passage configurations may be implemented, for example, the passages may not be grooves but rather buried within the rotor and have apertures on the rotor surface that allow communication across the respective seals. It may also be noted that first valve seal 18 may have a different angular orientation than second valve seal 20, such that the position of rotor passages 44, 42 will change accordingly.

The stator may be an injection type component, such as an injection type polymer, into which the seal is injected, for example in a two-step injection process. The seal may be injected into the elastomeric material, as is known per se in the art. The rotor 6 can also be injected with polymer, the stator and rotor thus forming a low cost disposable part.

The volume of fluid pumped by a full 360 degree rotation of the rotor 6 relative to the stator 4 is defined by the axial stroke of the rotor shaft 12 and the difference between the first and second diameters D1 and D2. By providing the rotor shaft with a smaller difference in the first and second diameters, a small amount of fluid can be pumped in the pumping cycle. However, the axial stroke of the rotor should have a sufficiently large amplitude to minimize the impact of manufacturing tolerances on the accuracy of the axial displacement. In certain applications, such as for the administration of concentrated drugs or the slow administration of drugs, although a micro-pump according to embodiments of the present invention may be provided to accurately pump amounts as small as two microliters per cycle, there may be an advantage of even less incremental amounts of fluid delivered than managed by a full rotation of the rotor shaft.

The axial displacement of the rotor 6 is a function of the angular displacement of the rotor, which is exerted by an axial displacement system comprising a biasing mechanism 9 and a cam system. The cam system includes a cam track 22, 22 'and a cam follower 36, 36' biased against the cam track by a biasing mechanism. In the illustrated embodiment, the cam tracks 22, 22 'are provided on the rotor head 10, while the cam projections 36, 36' are provided on the stator 4. However, it will be appreciated that the function of the cam track and cam projection could be reversed such that the cam projection is on the rotor and the cam track is on the stator without departing from the scope of the invention.

The cam tracks 22, 22' define the axial position of the rotor relative to the stator as a function of the angular position of the rotor relative to the stator. The axial displacement of the rotor is therefore a function of the rotational displacement of the rotor, which is defined by the profile of the cam track. Fig. 5 illustrates an example of a 360 degree deployment profile of the cam tracks 22, 22' according to an embodiment of the invention.

As best shown in fig. 4b, the cam system may include a pair of cam tracks and a corresponding pair of cam followers 36, 36'. There is a radially outward cam track 22 having a radius of curvature R1 and a radially inward cam track 22' having a radius of curvature R2, where R2 is less than R1. The first cam follower 36 is positioned to engage the radially outward cam track 22 and the second cam follower 36 'is positioned to engage the radially inward cam track 22'. The radially outward cam track and the radially inward cam track may define substantially the same axial displacement profile with a corresponding pair of cam followers 36, 36' depending on the angular displacement of the rotor. The concentric radial positions of the radially inward cam tracks and the radially outward cam tracks ensure that the radially outward cam projections 36 only engage with the radially outward cam tracks 22, while the radially inward cam projections 36 'only engage with the radially inward cam tracks 22'.

In a preferred embodiment, the radially inward cam track is diametrically opposed to the radially outward cam track, whereby the pair of cam tracks engaging the respective pair of cam followers increases the stability of the rotor 6. In particular, the biasing force F exerted on the rotor by the biasing mechanism 9 generates a resultant force aligned with the rotor axis a and which is thus counteracted by the reaction force of the cam follower on the corresponding cam track. The moment created by this biasing force will tend to tilt the rotor, resulting in increased friction and possibly undesirable vibrations. The pair of cam tracks 22, 22 'and corresponding cam followers 36, 36' provide a pair of diametrically opposed cam contact points that significantly reduce the tilting moment on the rotor, thereby improving stability and reducing potential vibration and wear problems.

It may be noted, however, that within the scope of the invention the cam system may comprise more than two cam tracks, for example three or four cam tracks and respectively three, four associated cam followers, each cam track and cam follower defining a substantially identical profile developed over 360 °, with the aim of providing a plurality of rotor support points to reduce the inclination of the rotor. The various cam tracks may have different radii such that each cam follower engages only one associated cam track. The cam tracks and cam followers may be evenly spaced at an angle about the rotor axis (e.g., one every 120 ° for three cam tracks).

With particular reference to fig. 5, the cam track 22, 22' profile includes an intake area 32 in the form of a ramp that extends from the valve-closing cavity chamber area 30 to the valve-closing full chamber area 28. Engagement of the intake zone 32 with the cam follower thus causes axial displacement of the rotor, with the intake valve V1 open and the exhaust valve V2 closed to fill the pump chamber 8. Once the pump chamber 8 is full, the inlet valve V1 is closed and the outlet valve V2 remains closed within a certain angular range prior to the discharge phase of the pumping cycle. Thus, both the inlet valve and the outlet valve are closed within a defined angular range to ensure that the inlet valve and the outlet valve are never opened simultaneously, thereby preventing a situation where fluid passes through the pump when the pump rotor is stationary. At the beginning of the discharge phase, the outlet valve V2 is opened while the inlet valve V1 remains closed and the discharge region 34 of the cam track engages the cam follower. The exhaust area 34 includes an exhaust ramp portion 34a, which exhaust ramp portion 34a causes axial displacement of the rotor from the valve-closing full chamber area 28 to the valve-closing chamber area 30.

According to an aspect of the invention, the discharge area 34 is provided with at least one discharge holding location 34 b. The discharge holding position 34b is located at an intermediate angular and axial position between the valve-closed full chamber area 28 and the valve-closed chamber area 30, and allows the rotor 6 to be stopped and stably held at the intermediate position.

Thus, in the embodiment shown in fig. 5, the delivery of fluid may be divided into two partial delivery phases, so as to manage the full volume of the pumping cycle in two partial delivery increments.

In a variation, two or more discharge hold positions may be provided to manage the full volume of the pumping cycle in three or more partial delivery increments. As shown in the example of fig. 6a and 6b, the discharge region of the cam track is provided with two discharge hold locations 34b separated by a discharge ramp portion 34a, thereby defining three partial delivery increments of the total discharge volume of the pumping cycle.

Advantageously, the discharge zone 34 is provided with one or more discharge hold locations 34b to accurately and reliably deliver portions of a full pumping cycle volume in multiple stages, allowing very small fluid doses to be delivered in time increments. It may be particularly useful to operate the micropump during a portion of the delivery phase of a complete pumping cycle to control the rate of administration of the fluid drug over a period of time. This allows, for example, a controlled slow quasi-continuous delivery (e.g., delivery basal rate) of the simulated drug. Such partial delivery of the pumping cycle volume may also be useful for very precise delivery of precise amounts of fluid, e.g. corresponding to a plurality of pumping cycles plus a portion of a pumping cycle. For example, if a full pumping cycle delivers a volume of 2 μ l and the cam track has a discharge holding position 34b axially intermediate between the valve-closed full chamber region 28 and the valve-closed chamber region 30, as shown in fig. 5 (i.e., two partial delivery phases), volumes corresponding to odd integers may be delivered. For example, to deliver 7 μ Ι, the pump can be operated to deliver 3.5 pumped circulation volumes by: the rotor is rotated three times and then stopped when the cam follower is engaged to the discharge holding position 34b during the fourth rotation.

In an advantageous embodiment, the drain holding location 34b may comprise a platform defining a surface substantially perpendicular to the axis of rotation a. The angular arc length of the discharge retention portion 34b may advantageously extend at least 15 degrees in order to provide a precise intermediate axial position (defining the discharge volume) with a certain tolerance for the angular stop position of the rotor with respect to the stator.

In a modification, the discharge ramp portion 34a may be configured to have a slope that allows reverse rotation of the rotor relative to the stator (reverse rotation being opposite to forward rotation corresponding to normal pumping operation). The reverse rotation of the rotor may be used for special operations of the pump including bidirectional flow for reconstitution of the drug, reverse rotor movement for actuating retraction of a needle of the drug delivery device, or other special operations. The slope of discharge ramp portion 34a preferably has an angle beta of about 45 degrees or less with respect to either valve-closed full chamber area 28 or valve-closed cavity area 30. However, in variations that do not provide for counter-rotation of the rotor, the discharge ramp portion 34a may have an angle between 45 and 90 degrees with respect to the full chamber area 28 and the chamber area 30.

The cam followers 36, 36' may advantageously be provided with a chamfered forward nose angle 38a and, for variants allowing reverse rotation, a chamfered reverse nose angle 38b to ensure a smooth transition of the cam followers 36, 36' on the associated cam tracks 22, 22' when travelling from the platform defined by the valve-closed full chamber area 28 and the chamber area 30 with the drain hold position 34b to the subsequent ramp portion.

When deployed at 360 degrees of rotation, adjusted for radii of curvature R1, R2, the diametrically opposed cam followers 36, 36 'and associated diametrically opposed cam tracks 22, 22' may have the same engagement profile.

In an embodiment of the invention, the motor 5 of the rotary drive 3 may advantageously be in the form of a stepper motor comprising steps angularly spaced apart by increments smaller than the angular extent of the discharge region 34 of the cam track 22. The rotor 6 engaged by the stepper motor may stop at a selected step of the stepper motor to stop and hold the rotor as the cam follower engages along the discharge region of the cam track. Thus, for example, as shown in fig. 7, one or more intermediate discharge holding locations 34b may be defined by a step of the motor to deliver a portion of the full volume of the pumping cycle. It may be noted that the stepper motor and any reduction gear system between the stepper motor and the rotor 6 may include multiple positions between the defined discharge holding positions 34 b. The rotary drive may comprise a stroke sensor (not shown) for measuring the axial displacement of the rotor 6 relative to the stator. The travel sensor may comprise an optical or magnetic position sensor, or other known position sensors known per se in the art of position sensing. The stroke sensor may be connected to the control electronics of the rotary drive to control the stepper motor, in particular to stop at a selected ejection holding position. The stroke sensor may also be used to detect erroneous operation of the micro-pump.

In a variant, the micro-pump may comprise a combination of the discharge holding position 34b (which comprises the platform) and the control of the stepper motor in the rotary drive of the micro-pump to define a further intermediate discharge holding position.

List of illustrated features

Micropump 1

Pump module 2 (Disposable parts)

Stator 4

Inlet 14

An outlet 16

First valve V1

First valve seal 18

Second valve V2

Second valve seal 20

Pump chamber seal 21

Cam system

Cam followers 36, 36'

Rotor 6

Rotor head 10

Transmission input coupler

Cam system

Cam rails 22, 22'

Radially outward cam track 22

Radius of curvature R1

Radially inward cam track 22'

Radius of curvature R2

(R2<R1)

Rotor shaft 12

First extension (having first diameter D1)24

First passage 42

Second extension (having second diameter D2)26

Second passage 44

Pump chamber 8

Axial displacement system

Biasing mechanism 9

Cam rails 22, 22'

Valve closes off the full chamber area 28

Valve-closing cavity chamber area 30

Air intake zone 32

Discharge region 34

Discharge ramp portion 34a

The discharge holding portion 34b

Cam followers 36, 36'

Front corners 38a, 38b

Rotary driver 3 (reusable parts)

Motor 5

Stepping motor

Coupling 7

Biasing mechanism 9

Stroke sensor