WO2020161130A1

WO2020161130A1 - Suction pump

Info

Publication number: WO2020161130A1
Application number: PCT/EP2020/052742
Authority: WO
Inventors: Etienne Furrer; Cornel Bächler; Armin Felber; Stefan Hofstetter; Regina MARBET; Andreas Walter
Original assignee: Medela Holding Ag
Priority date: 2019-02-07
Filing date: 2020-02-04
Publication date: 2020-08-13
Also published as: EP3693037A1

Abstract

The present invention refers to a motor-driven medical suction pump, in particular a breast pump, with a pump unit (6) for generating a negative pressure, which is accommodated in a pump housing (2, 4). In order to create a medical suction pump which is inexpensive, nevertheless efficient but also improved in terms of noise generation and vibration and of compact design, the present invention proposes to provide at least two pumping entities (50) for generating the negative pressure as a component of the pump unit (6). According to an alternative aspect of the present invention, a passive pressure compensation chamber (45) is provided in the pump housing (2, 4), which communicates with a suction side of the pump unit (6).

Description

Suction pump

The present invention refers to a motor-driven medical suction pump, in particular a breast pump, with a pump unit for generating a negative pressure, which is accommodated in a pump housing.

Such a suction pump is known for example from US 8,876,760 B2.

The suction pump according to the invention as well as the known suction pump, is used in particular for sucking breast milk from the female breast. However, the suction pump according to the invention can also be used for other medical purposes, for example for suctioning wound secretions from the wound area.

In the aforementioned state of the art, a buffer chamber with variable volume is located between the motor that generates the negative pressure and a diaphragm that separates the working medium of the motor from the fluid to be sucked in. For this purpose, the buffer chamber has a piston provided by a motor, through which the volume of the buffer can be changed in order to vary the negative pressure of the working medium applied to the diaphragm.

The present invention is based on the problem of providing a motor-driven medical suction pump that can be manufactured cost-effectively, can be operated with as little vibration and noise as possible and has a compact design.

To solve this problem, this invention proposes a motor-driven medical pumping entities of the type mentioned above, in which the pump unit has at least two individual drives like motors to generate the negative pressure. The pumping entities of the invention are each individual units or entities, which entities each comprise an individual drive for generating a negative pressure. Such drive may be an electric motor which cyclically or continuously rotates. The drive may likewise be formed of a piezo motor. Those drives cooperates with means for producing a negative pressure. Each of the pumping entities may comprise a different drive. Accordingly, one of the units may comprise an electric motor, while the other may comprise a piezo motor. The motors of the pump unit according to the invention are each drives or motors for generating the negative pressure. The motors each have directly assigned pump chambers, whose volumes can be changed by the operation of the motors to achieve a suction power. The pump chamber is usually formed by a movable diaphragm forming means for producing a negative pressure, which means are activated by the drive. The movable diaphragm is cyclically reciprocated by an eccentrically or cyclically moving drive element directly connected to the output side of the drive, which on a regular basis is the motor axis. A motor-driven valve is directly assigned to each pump chamber in order to introduce ambient air into the variable pump chamber. The two pumping entities are usually of identical design. In other words, the individual components of the pumping entities, including the pump chambers, are identical, which favors the economical manufacture of the suction pump according to the invention. The pump chamber, the inlet valve and the drive are usually connected to each other to form the pumping entity. The suction opening of each individual pump chamber associated with the drives or motors is usually connected to a uniform adapter element which has hose connections for hoses leading to a suction opening on the outside of the pump housing.

While the solution according to the invention has at least two motors for generating the negative pressure, the aforementioned solution according to US 8,876,760 B2 has only one such motor with an assigned pump chamber. The working medium is introduced from this pump chamber into the buffer, the volume of which is variable. Here only the level of the initially generated negative pressure is changed, without the motor itself having a function generating the negative pressure of the working medium.

The arrangement of two smaller motors instead of one large motor offers advantages when designing the suction pump. It can be operated with less vibration as the moving masses of two motors are not necessarily moved synchronously. The suction pump according to the invention can also be manufactured more cost-effectively if the two motors and the pump chambers assigned to them are manufactured using the same components.

According to a secondary aspect of the present invention, the suction side of the pump unit communicates with a passive pressure compensation chamber which is accommodated in the pump housing. Such a passive pressure compensation chamber increases the volume of the working medium provided in the suction pump, so that it can react better to varying influences, such as those introduced by the fluid to be sucked in. System-related variations in the volume formed on the side of the fluid to be sucked in, or spontaneous changes in the pressure conditions acting there, can be better compensated for by the suction pump according to the invention due to the passive pressure compensation chamber. The pressure compensation chamber is located between the pump unit and a diaphragm which separates the working medium from the medium to be sucked in. The pump housing preferably has a suction opening, which makes the suction power of the suction pump available on the outside of the pump housing without interposition of a diaphragm.

The passive pressure compensation chamber according to the invention has a fixed volume. In contrast to the aforementioned state of the art according to US 8,876,760 B2, there is no active actuator for changing the position of a diaphragm. The volume of the pressure compensation chamber is fixed. The walls of the pressure compensation chamber are not motor-driven. Subject to any deformation of the walls defining the pressure compensation chamber due to changing pressure conditions, the chamber walls are to be regarded as rigid. The volume of the pressure compensation chamber cannot be actively changed.

In view of a lower vibration of the suction pump during operation, it is proposed, in accordance with a preferred further development of the present invention, to arrange the motors relative to each other in such a way that the free mass forces of the motors or the pump unit are at least partially balanced during operation of the motors. Such a balance can be achieved, for example, by rotating the two motors in opposite directions. This prevents the free mass forces of the individual motors from increasing in any case. This positive effect is particularly evident when the suction pump is started up. A design in which the mass forces are fully or partially balanced can also be achieved by arranging the pump chambers on opposite sides of the individual motors with respect to the longitudinal axis of the motors. The pistons of the pump chambers are preferably arranged essentially axially parallel to each other, but are arranged on opposite sides in relation to the longitudinal axis of the motors and/or operated in opposite directions to each other in such a way that the vibrations or free mass forces of the pistons are balanced. The motors can be controlled in such a way that they are actuated phase-shifted. This also results in at least partial compensation of free mass forces. In this context, stepper motors are to be preferred, which can be precisely controlled to this extent. However, even with simpler electric motors, there is a reduced oscillation triggered by the drives if they are operated at least in opposite directions.

With this in mind, too, it is proposed that the drive shafts should run at least approximately parallel to each other, in accordance with the preferred further development of the present invention. The drive shafts are usually the drive rotary axes of the drive motors. The drive shafts are arranged side-by-side. The drive or motor shafts are not arranged coaxially. This design leads to effective vibration suppression, especially with counter-rotating motors.

In order to achieve the best possible damping of noise and vibrations, the motors are accommodated in a pump unit housing in accordance with the preferred further development of the present invention. The pump unit housing encapsulates the motors and usually also the pump chambers assigned to them in a sound-absorbing manner. For this purpose, the motors are usually completely surrounded by the pump unit housing. Noise from the motors cannot penetrate directly to the outside. Rather, it is trapped inside the pump unit housing.

The vibration of the motor and the damping of structure- borne noise associated with the operation of the motors can be particularly dampened in accordance with the preferred further development of the present invention by the fact that the pump unit housing accommodating the motors is suspended elastically in the pump housing. The suspension of the pump unit housing is usually carried out via only two bearing points. The suspension is usually designed in such a way that the pump unit housing can perform translational and rotational compensatory movements in the pump housing without colliding with the walls of the pump housing. Contact is made solely via bearing points, which are usually damping or elastic.

To realize the suspension, the pump unit housing preferably has bearing pins protruding from the outer surface, which are each accommodated in assigned support elements. The support elements are usually made of an elastic material such as TPE or silicone. The support elements are fixed with respect to the pump housing. However, the support elements usually have no direct contact with the outer walls of the pump housing. The bearing pins are usually located at the level of the center of mass of the pump unit housing together with the components accommodated therein. Bearing pins are usually provided on opposite outer surfaces of the pump unit housing.

The straight line connecting the bearing pins preferably extends obliquely to a straight line intersecting the drive shafts. This concrete design follows the general guideline according to which the motor axes of the motors run at least approximately parallel to each other and a first straight line intersecting the motor drive runs at an angle to a second straight line which connects two support points at each of which a support element acts on the outside of the pump unit housing. The angle enclosed by both straight lines is preferably between 15° and 90°, especially between 30° and 60°.

The support elements are usually held in a sliding guide. This sliding guide is formed partly by a lower housing part and partly by an upper housing part, each of which is usually in the form of a hood or shell and is designed as injection-molded plastic elements. The sliding guide is accordingly formed by a lower sliding guide and an upper sliding guide, which are assigned to the lower and upper housing parts respectively. After joining the upper and lower parts of the housing, the support elements are fitted into the housing via the sliding guide without play. The support element can, for example, be pre-assembled in the upper sliding guide, whereby the lower sliding guide provided on the lower part of the housing slides over the support element when the upper part of the housing and the lower part of the housing are joined and fixes the support element in the direction of sliding basically without play after the housing has been assembled.

The passive pressure compensation chamber is usually located above the pump unit in the height direction. Accordingly, the pressure compensation chamber is assigned to an upper end of the upper part of the housing. The suction opening of the suction pump is usually located in the upper part of the suction pump standing on the bottom formed by the lower housing part. The pressure compensation chamber is directly assigned to this suction opening.

The upper part of the housing forms the pressure compensation chamber at least partially. In other words, at least part of the pressure compensation chamber is formed by the injection- molded upper part of the housing. Thus, the upper part of the housing can form a pressure compensation chamber shell which is closed by an essentially planar pressure compensation chamber cover provided with a connection piece. This pressure compensation chamber cover is usually gas-tightly connected to the pressure compensation chamber shell by ultrasonic welding or laser welding, thus completing the passive pressure compensation chamber.

The pressure compensation chamber is usually formed by several, preferably two, components which are spatially fixed. The aforementioned connection piece is preferably accommodated in a housing cover and protrudes into it. The housing cover is preferably made of an elastic material, so that an outlet duct surrounding the connection piece and leading to the suction opening is sealed against the connection piece. The outlet duct is preferably formed by the housing cover alone, which directly covers the pressure compensation chamber.

The elastic material of the housing cover allows the forming of one, usually several, key elements to control the pump unit on the housing cover. For this purpose, an assembled printed circuit board (PCB) is usually provided between the pressure compensation chamber and the housing cover, which is equipped with switches opposite the key elements of the housing cover, so that touching the key elements leads to an electrical control signal. The housing cover is usually essentially flat and even on the outside, also with regard to hygienic requirements. On the opposite inner side, the housing cover usually has webs which act as elastic support webs against the printed circuit board and fix it in the direction of the upper part of the housing. On the side of the printed circuit board opposite the support webs of the housing cover, there are bearing segments of a PCB support frame which holds and fixes the printed circuit board. This PCB support frame regularly has an upstanding or even interrupted circumferential edge which is surrounded by a retaining edge of the housing cover so that the electronic components are not only enclosed from above but also laterally by the housing cover. The printed circuit board usually has plug contacts for the electrical connection of cables leading to the individual motors.

The mechanical fixing of the PCB and the housing cover is usually done by latching the PCB support frame to the upper part of the housing. The PCB support frame usually lies directly above the pressure compensation chamber, preferably against the pressure compensation chamber at the top. The latching between the housing cover and the PCB support frame is usually secured in the assembled state by a projecting edge of the upper part of the housing, which also preferably forms a latching connection with the outer circumferential surface of the retaining edge of the housing cover. This creates a kind of labyrinth seal between the upper housing element, the housing cover and the PCB support frame, which reliably prevents moisture and dirt from entering the pump and in particular the electronic components of the suction pump.

The printed circuit board covered by the housing cover can have at least one LED, which is usually connected to the printed circuit board using SMD technology. Such an LED can be used to give optical hints or commands to the user of the pump. The LED is usually controlled by a logic unit mounted on the PCB.

Further details and advantages of the present invention can be found in the following description of an embodiment in connection with the drawing:

Figure 1 shows a perspective exploded view with all components of the embodiment;

Figure 2 shows a longitudinal view of the embodiment;

Figure 3 shows a further longitudinal view of the embodiment further outside with respect to Figure 2; Figure 4 shows a cross-sectional view of the embodiment through the pump unit;

Figure 5 shows a further cross-sectional view of the embodiment through the pump unit, which is further lower with respect to Figure 4; and

Figure 6 shows a perspective side view of the embodiment with the lower housing part removed.

Figure 1 shows an upper housing part 2 and a lower housing part 4 of the housing, which enclose a pump unit 6 between them, which is supported against the upper housing part 2 and the lower housing part 4 by support elements 8. The pump unit 6 has a pump unit housing which is formed from two latched pump unit housing parts 9, 11 , marked with reference numeral 10 in the following Figures and which has bearing pins 12 for this purpose, which are recessed in pin receptacles 14 of the associated support element 8 (see Figure 3). The pump unit housing 10 is made of plastic material.

When assembled, a textile retaining strap 16 projects from the outer circumferential surface of the upper housing part 2, over which the suction pump can be carried. Reference numeral 18 indicates a housing cover which accommodates further components shown in Figure 1 which are connected to the housing cover 18 by latching. The housing cover 18 and the support elements 8 are made of silicone, the remaining housing parts 2, 4, 6 are made of a common technical plastic material, for example PC, PP or PA.

The other components accommodated in the housing cover 18 are an assembled printed circuit board (PCB) 20 and a PCB support frame 22, which is provided on the side of the PCB 20 opposite the housing cover 18. Below the PCB support frame 22, Figure 1 shows a pressure compensation chamber cover 24 which is ultrasonically welded to the upper housing part 2. The upper housing part 2 has a pressure compensation chamber shell 26. This pressure compensation chamber shell 26 is an integral part of the one-piece injection- molded upper housing part 2. The PCB support frame 22 has latching lugs projecting in the direction of the upper housing part 2, which are latched into latching openings formed on the upper housing part 2. As Figure 2 in particular shows, the housing cover 18 has a circumferential retaining edge 28 which is locked with a support edge 30 which is formed by the PCB support frame 22. Figure 2 shows the housing cover 18 encircled by a step of the PCB support frame 22. The PCB support frame 22 has a grid pattern and supports the PCB 20 in discrete locations. The PCB support frame 22 has an inner support ring 32 which is provided on the lower side of the PCB 20 and serves as an abutment segment 33 for support webs which are formed in one piece by the housing cover 18 and are marked with the reference numeral 34 in Figure 2. This design, however, holds and supports the PCB 20 elastically in the upper portion of the upper housing part 2 with a certain pretension.

The upper housing part 2 has an upper circumferential edge 36, which surrounds the retaining edge 28 of the housing cover 18 circumferentially and thus provides a higher tightness against environmental influences, so that neither dirt nor moisture can reach the PCB 20. As shown in Figure 2, the housing cover 18 has a circumferential edge on its retaining edge 28 which engages a corresponding circumferential groove in the upper circumferential edge 36. This increases the tightness and mechanically locks the two parts.

Reference numeral 41 indicates a rechargeable power source (battery).

The sectional view according to Figure 2 shows that the upper housing part 2 forms a mounting socket 38 projecting from the bottom of the pressure compensation chamber shell 26, which ends opposite a mounting socket 40 of the lower housing part 4 and is provided with a threaded bore 42. On the side opposite the threaded bore 42, the mounting socket 38 surrounds a conical chamber volume 44 which communicates with the chamber volume enclosed between the bottom of the pressure compensation chamber shell 26 and the pressure compensation chamber cover 24 welded thereto.

These two volumes together form a passive pressure compensation chamber 45 within the pump housing 2, 4 of the suction pump, the compensation volume of which is predetermined and fixed.

From the lower side of the bottom of the pressure compensation chamber shell 26 protrude connection sockets which are integrally formed on the upper housing part 2 and serve for the connection of two hoses 46. The exact connection of the hoses 46 is shown in particular in Figure 6. The hoses 46 extend from the bottom of the pump unit housing 10 to the bottom of the pressure compensation chamber shell 26. Thus, each of the hoses 46 communicates with the pressure compensation chamber 45. The access of the hoses 46 to the pressure compensation chamber 45 is marked in Figure 4 with the reference numeral 48. The suction side of the pump unit 6 communicates with the pressure compensation chamber 45 via the hoses 46. As Figures 4 and 5 in particular show, the pump unit has two identical electric motors 50. Motor shafts marked with reference numeral 52 run parallel to each other and in the height direction of the embodiment of the suction pump. The shafts 52 projecting beyond the housing of the motors 50 are each provided with an eccentric disc, which is surrounded circumferentially by an elastomer ring, which is integrally formed on a diaphragm, which closes a chamber of a pump module as a movable piston. The outer edge of the piston is fixed to the housing, so that only the middle area of the piston is cyclically moved back and forth due to the rotation of the eccentric disc. In the sectional view shown in Figures 4 and 5, the pump module marked 54 in Figure 2 is substantially to the right of the lower motor 50 and to the left of the upper motor 50. The pump module 54 has an electromagnetic valve 56 for inlet of ambient air depending on the pump cycle of the pump module 54.

An adapter element marked with a reference numeral 58 in Figure 2 accommodates the suction openings of the two pump modules 54. The adapter element 58 is made of an elastic material (silicone) and supports the motors 50 in a damping manner against the pump unit housing 10. The adapter element 58 communicates sealingly on the one hand with the suction opening of each of the pump modules 54 and on the other hand with hose connections for connecting the hoses 46, which are arranged outside on the pump unit housing part at its bottom. Figures 4 and 5 show that the pump modules 54 and the motors 50 are identical. The arrows marked with a reference numeral D indicate the direction of rotation of the motors 50 during operation. The lower motor 40 runs counterclockwise; the upper motor 50 clockwise. The arrangement of the pump modules 54 on opposite sides of the motors 50 compensates the free mass forces of the pump unit. By rotating the motors 50 in the opposite direction, the free mass forces of the motors 50 are balanced. Thus, the free mass forces of the pump unit are at least partially balanced when the motors 50 are operated.

Figures 3 and 5 further illustrate the accommodation of the support elements 8 in sliding guides 60; sliding guides 60 for each support element 8 consist of a lower sliding guide associated with the lower housing part 4 and marked with a reference numeral 62 and an upper sliding guide 64 associated with the upper housing part 2; the lower and upper sliding guides 62 and 64 are each integrally formed on the upper housing part 2 and lower housing part 4. The upper and lower sliding guides 62, 64 each have two opposite U-shaped receptacles which taper towards their free ends. The middle part of the support element 8 in the direction of height lies between the free ends of the upper and lower sliding guides 62, 64. As shown in Figure 6, the support element 8 can first be inserted into the upper housing part 2 assembly, so that the support element 8 is accommodated in the lower sliding guide 64 in each case. Previously, the support element 8 was pushed onto the opposite bearing pins 12 of the pump unit housing 10 so that the pump unit 6 is suspended elastically inside the housing parts 2, 4 via the pins 14. As Figure 3 shows in particular, this suspension of the pump unit housing 10 is carried out in such a way that it is provided completely with sufficient distance from the surfaces of the upper housing part 2 or the lower housing part 4. Thus, the pump unit housing 10 can carry out compensatory movements within limits, translatory or rotatory, to compensate for internal vibrations without colliding with the pump housing 2, 4.

Figure 3 shows details of the support element 8. This consists of a frame with legs extending orthogonally to each other, in which diagonal webs 66 lead to the pin receptacle 14 and surround it circumferentially. Cross webs 68 also extend from the longitudinal legs of the frame, which extend in the direction of the height, and also connect to the pivot receptacle 14. The elastic material and this concrete design of the support element 8 results in good mobility and damping of the pump unit housing 10 for compensating vibrations during operation of the motors 50. The support element 8 is clamped and thus fixed in height direction between the upper housing part 2 and the lower housing part 4.

The housing cover 18 has various functions. As Figure 1 shows, the elastic housing cover 18 forms several key elements 70. The mobility of the key elements 70 results from the elastic material properties of the silicone of the housing cover 18 on the one hand and the thin- walled structure of the outer surface of the housing cover 18 on the other hand. Below the key elements 70 there are push-buttons, which can be seen in Figure 2 and are marked with the reference numeral 72. This allows a suction pump user to press on the top of the housing cover 18 at circumferentially spaced points on the outer surface of the housing cover 18, marked by symbols, to enter specific control commands for the control of the pump unit 6.

The housing cover 18 also forms a suction opening for connection to a suction hose, marked by reference numeral 74 in Figures 1 and 3. This suction hose may have a luer cannula which can be inserted into an outlet duct marked by reference numeral 76. The elastic properties of the housing cover 18 result directly in a seal. These elastic properties also ensure a fluid-tight connection between the housing cover 18 and the pressure compensation chamber cover 24, which forms a one-piece connection socket marked by reference numeral 78 in Figure 2, which is fitted sealingly into the housing cover 18 by engaging one end of the outlet duct 76. Figure 4 illustrates the relationship between a first straight line G1 connecting the two motor shafts 52 and a second straight line G2 connecting two support points formed by the bearing pins 12. Such an inclined support has proved to be advantageous for further damping of the pump unit 6 compared to the pump housing 4, 6. The angle a enclosed by the two straight lines G1 , G2 is about 35°. It should be at least 15°, but not more than 90°. Ideally, the angle should be between 20° and 70°, preferably between 30° and 60°.

List of reference numerals upper housing part

lower housing part

pump unit

supporting element

pump unit housing part

pump unit housing

pump unit housing part

bearing pin

pin receptacle

textile retaining strap

housing cover

PCB PCB support frame

pressure compensation chamber cover

pressure compensation chamber shell

retaining edge

support edge of the PCB support frame 22 support ring

abutment segment

support web

upper circumferential edge of upper housing part 2 mounting socket of the upper housing part 2 mounting socket of the lower housing part 4 threaded bore

battery

chamber volume

pressure compensation chamber

hose

access

motor

motor shaft

pump module

valve

adapter element

sliding guide

lower sliding guide

upper sliding guide

web

cross web

key element

key switch

suction opening

outlet duct

connection pipe

Claims

Patent claims

1. Motor-driven medical suction pump, in particular a breast pump, having a pump unit (6) for generating a negative pressure, said pump unit being accommodated in a pump housing (2, 4),

characterized in that

the pump unit (6) has at least two pumping entities (50) for generating the negative pressure.

2. Motor-driven medical suction pump according to claim 1 , characterized in that the pumping entities (50) are arranged relative to one another in such a way that, during operation of the pumping entities (50), the free mass forces of the pump unit (6) are at least partially balanced.

3. Motor-driven medical suction pump according to claim 1 or 2, characterized in that the drive shafts (52) of the pumping entities (50) run at least approximately parallel to one another.

4. Motor-driven medical suction pump according to one of the preceding claims, characterized by a pump unit housing (10) which accommodates the motors (50) and is suspended elastically in the pump housing (2, 4).

5. Motor-driven medical suction pump according to one of the preceding claims, characterized in that the pumping entities (50) are encapsulated in the pump unit housing (10).

6. Motor-driven medical suction pump according to one of the preceding claims, characterized in that the drive shafts (52) of the pumping entities (50) run at least approximately parallel to one another and a first straight line (G1) intersecting the drive shaft (52) runs at an angle (a) to a second straight line (G2) which connects two support points (12) at each of which a support element (8) engages externally on the pump unit housing (10) and that the angle (a) is between 15° and 90°.

7. Motor-driven medical suction pump according to one of the preceding claims, characterized in that bearing pins (12) project from the outer surface of the pump unit housing (10) and engage in each case in pin receptacles (14) recessed on the associated supporting element (8).

8. Motor-driven medical suction pump according to one of the preceding claims, characterized in that the support element (8) is arranged between an inner surface of the housing (2, 4) and an outer surface of the pump unit housing (10) at a distance from the inner surface of the housing (2, 4).

9. Motor-driven medical suction pump according to one of the preceding claims, characterized by a sliding guide (60) for holding the supporting element (8).

10. Motor-driven medical suction pump according to claim 9, characterized in that the sliding guide (60) is formed partly on the lower housing part (4) and partly on the upper housing part (2).

11. Motor-driven medical suction pump, in particular a breast pump, having a pump unit (6) for generating a negative pressure, which is accommodated in a pump housing (2, 4), in particular according to one of claims 1 to 10,

characterized by

a passive pressure compensation chamber (45) received in the pump housing (2, 4) and communicating with a suction side of the pump unit (6).

12. Motor-driven medical suction pump according to claim 11 , characterized in that the pump housing (2, 4) has a lower housing part (4) forming a standing surface of the housing and an upper housing part (2) closing the pump housing on the upper side, which upper and lower housing part (2, 4) enclose the pump unit (6) between them, the pressure compensation chamber (45) being assigned to an upper end of the upper housing part (2) and being provided above the pump unit (6).

13. Motor-driven medical suction pump according to claim 12, characterized in that the pressure compensation chamber (45) is at least partially formed by the upper housing part (2).

14. Motor-driven medical suction pump according to claim 13, characterized by a housing cover (18) made of an elastic plastic material which forms at least one key element (70) for controlling the pump unit (6).