Device for gravity-driven control of the filling pressure of a catheter balloon

Abstract

Device for gravity-driven, particularly continuous, control of the filling pressure in a balloon catheter (3), comprising: a balloon reservoir that is statically loaded with a vertically guided weight guide or stamp (9) that weighs vertically on the balloon reservoir, wherein said weight guide or stamp is designed to carry vertically arranged and therewith plumb-vertically acting weight elements (8), and wherein the balloon reservoir is guided in a cylindrical shell (6).

Claims

1. A device for gravity-driven control of a filling pressure in a balloon catheter, comprising: a balloon reservoir that is statically loaded with a vertically guided weight guide that weighs vertically on the balloon reservoir, wherein said weight guide is configured to carry vertically arranged and therewith plumb-vertically acting weight elements, wherein the balloon reservoir is guided in a cylindrical shell, wherein the balloon reservoir is housed in two cup-like half-shells, and wherein said half-shells guide the balloon reservoir in the cylindrical shell.

2. The device as claimed in claim 1, wherein the balloon reservoir is housed in a lower cup-like half shell and an upper cup-like half shell.

3. The device as claimed in claim 2, wherein the two cup-like half-shells each comprise an inner surface, wherein the balloon reservoir is designed to deploy in a filled state of the balloon reservoir into the inner surfaces, and to push the two half-shells apart, so as to generate a gap between the half-shells, said gap serves as an indicator for the filling pressure in the balloon reservoir adjusted by a user.

4. The device as claimed in claim 2, wherein in a deflated state of the balloon reservoir or when a preset filling pressure is undercut, the two cuplike half-shells butt against each other, via a collapsed envelope of the balloon reservoir, in the cylindrical shell guiding the cup-like half-shells.

5. The device according to claim 2, wherein the balloon reservoir is formed in an elongated or cylindrical shape and is adapted to inner surfaces of the cup-like half shells.

6. The device according to claim 2, wherein the balloon reservoir comprises a cylindrical length that allows for generating a gap between the cup-like half-shells in the range from 1 cm to 5 cm in a filled but unstretched state of an envelope of the balloon reservoir.

7. The device as claimed in claim 2, further comprising the upper cup-like half-shell is connected to a fall cross being designed to plumb-vertically guide said weight elements, wherein the upper cup-like half-shell comprises a central bore hole into which a plug-like connection member is inserted, which connects the upper cup-like half-shell to said fall cross.

8. The device as claimed in claim 7, wherein the fall cross comprises four legs or recesses, each leg or recess comprising at least one roll-like element, which guides the fall cross on an inner side of the cylindrical shell, wherein the fall cross is connected to said weight guide, wherein the fall cross comprises a through-borehole; a lower side of the fall cross connects to the upper cup-like half-shell and an upper side of the fall cross receives said weight guide; said weight guide is configured to receive said weight elements in the form of weight rings, and wherein said weight guide is connected to the fall cross, substantially without play, so that said weight guide can be released from the fall cross and removed upwards from the cylindrical shell for providing said weight guide with the respectively required weight elements.

9. The device according to claim 2, wherein an outer visible surface of the cup-like half-shells comprises a signal colour.

10. The device according to claim 2, wherein the cylindrical shell comprises a closure element for closing an upper opening delimited by an upper face side of the cylindrical shell, wherein the closure element comprises a central through-opening for receiving a free end of the weight guide, wherein the free end of the weight guide protrudes out of the cylindrical shell through said through-opening when a gap is present between the two cup-like half-shells.

11. The device according to claim 2, wherein the cylindrical shell comprises at least one of a first marking indicating a minimum gap height of a gap between the two cup-like half-shells, particularly allowing for easy visual recognition of the gap and corresponding to a sufficient volume reserve, or a second marking indicating a maximal gap height of a gap between the two cup-like half-shells, selected such that the balloon reservoir is not fully deployed along its longitudinal axis when the maximal gap height is reached, so as to avoid stretching of an envelope of the balloon reservoir.

12. The device according to claim 1, further comprising the balloon reservoir is at its lower end bonded in a firm and sealing manner with a plug-like member, which comprises a continuous bore hole for connecting to a filling hose, wherein said hose connection is bonded into a lower end of the plug-like member.

13. The device as claimed in claim 1, wherein the weight guide comprises a vertically guided stamp that weighs vertically on the balloon reservoir, wherein said stamp is designed to carry vertically arranged and therewith vertically acting weight elements.

14. The device as claimed in claim 1, wherein the weight guide comprises a guide cup for receiving weight elements.

15. The device as claimed in claim 14, wherein the guide cup is connected to an upper cup-like half-shell, wherein the guide cup is connected on a lower side by a pin to the upper cup-like half-shell.

16. The device as claimed in claim 14, wherein the guide cup is connected to an upper end of the balloon reservoir, wherein the upper end of the balloon reservoir is connected to a bottom of the guide cup by means of a plug-like member, and wherein the balloon reservoir is vertically guided in the cylindrical shell by the guide cup.

17. The device according to claim 1, wherein the balloon reservoir comprises an envelope having a thickness in the range of 5 μm to 20 μm.

18. The device according to claim 1, wherein the cylindrical shell is made out of a transparent material.

19. The device according to claim 1, characterized in that the balloon reservoir consists of a thin-walled foil material having a Shore hardness in the range of 55D to 60D so as to restrict the radial stretchability of the balloon reservoir for filling pressures up to 100 mbar, such that the balloon reservoir does not contact an inner side of the cylindrical shell when being in a filled state with a filling pressure of up to 100 mbar.

20. The device according to claim 1, wherein the balloon reservoir is made out of a transparent material.

21. The device according to claim 1, characterized in that the weight elements are designed to be vertically arranged on top of each other on the weight guide so that a visible gap exists between adjacent weight elements, allowing for easy counting of the weight elements, wherein the weight elements comprise a weight used in clinical practice.

22. A system comprising: a device for gravity-driven control of the filling pressure in a balloon catheter, wherein the device comprises a balloon reservoir that is statically loaded with a vertically guided weight guide that weighs vertically on the balloon reservoir, wherein said weight guide is configured to carry vertically arranged and therewith plumb-vertically acting weight elements, wherein the balloon reservoir is guided in a cylindrical shell, wherein the balloon reservoir is housed in two cup-like half-shells, and wherein said half-shells guide the balloon reservoir in the cylindrical shell; a filling hose; and a three-way valve, wherein the filling hose connects the three-way valve to the balloon reservoir.

23. The system according to claim 22, further comprising a filling device, in the form of a syringe, for filling the balloon reservoir with a medium, and a balloon catheter, wherein said three-way valve is designed to connect the balloon catheter, the filling device and the control device, so as to form a communicating system, and wherein a syringe volume for receiving said medium is selected such that is allows for adjusting a gap between the cup-like half-shells in the range of 1 cm to 5 cm when injecting the medium into the balloon reservoir by means of the syringe via the three-way valve.

24. The system according to claim 22, characterized in that the balloon reservoir is permanently connected to the filling hose in a sealing manner, and in that the filling hose is permanently connected to the three-way valve in a sealing manner, so that the balloon reservoir, the filling hose and the three-way valve form a permanently connected unit that is designed to be replaced as a whole.

Description

(1) FIG. 1 shows an overview of the system, in which the controller unit is connected as an example with a low-pressure balloon catheter (ventilation tube) and a filling device (injection syringe);

(2) FIG. 2 shows the housing according to the invention of the reservoir balloon in a lower and upper cup guide and describes the configuration of the balloon with respect to the other controller components;

(3) FIGS. 2a and 2b show the structural interaction of the reservoir balloon and the cup guides in the filled and emptied balloon state;

(4) FIG. 3 describes in a special embodiment of the invention a vertical guide of the weights by means of a fall cross as well as a stacked reception of the weights by means of a stamp element, which can be placed on top of the fall cross;

(5) FIG. 3a shows a specific embodiment of a friction-reduced gliding wheel-supported fall cross;

(6) FIGS. 4a and 4b show as an alternative to the embodiment comprising a fall cross a simple cup guide for receiving ball weights;

(7) FIG. 5 describes preferred volume markings on the cylinder body (i.e. cylindrical shell);

(8) FIG. 6 shows an embodiment of the pressure or volume receiving system built as a continuous unit; and

(9) FIG. 7 shows exemplary ring weights.

(10) FIG. 1 shows an overview of the system, wherein a device according to the invention (also denoted as controller or controller unit) 1 is connected via the filling device 2 (syringe element) with a balloon catheter 3 (tracheal tube). The filling by means of a separate filling device 2 is preferably carried out by means of a three-way valve 4. The valve 4 connects all system components, thus the controller 1, the catheter 3 connected to the controller 1 and the filling device 2 to a (particularly pressure-) communicating system. On the lateral leg of the valve 4 preferably a customary syringe 2 can be plugged on as a filling device 2, alternatively a pump balloon or a hand-operated pump manometer can be connected as well. The syringe volume is preferably chosen such that it facilitates a gap between the cup guides (i.e. cup-like half-shells 11a, 11b) of the balloon body (also denoted as balloon, reservoir balloon, or balloon reservoir) 10 of at least one centimeter, but as far as possible not more than 5 centimeters.

(11) The foot unit or the foot plate 5 (e.g. having a diameter of 130 mm) of the controller 1 preferably consists of anodized aluminum and is configured such that it ensures the safe and vertical stand of the device 1. As a preferred embodiment the foot unit 5 is furthermore furnished with an integrated holding claw 5a for fastening to a usual clinic equipment rail.

(12) The tube cylinder (i.e. cylindrical shell) 6 is vertically plugged into the foot unit 5 and (in the connection region) held free of clearance by means of an optional O-ring. On the bottom side the plate or foot unit 5 is preferably furnished with one or more millings and/or bores, which facilitate a (particularly strain-relieved) exiting of the filling hose 14 connected to the balloon reservoir 10 out of the device 1. The cylinder or cylinder tube 6 preferably consists of particularly transparent acrylic glass (e.g. Plexiglass) and is particularly chosen such with respect to its height and its inner diameter that all embodiments of the controller unit 1 can be implemented. Furthermore, in the embodiment shown here, the cylinder 6 comprises an upper cap segment 6a, which is plugged onto the lower cylinder segment 6b and closed upwards by means of a lid (i.e. closure element) 7. The length of the so segmented cylinder 6 is preferably chosen such that the surface of the lid element 7 in the non-impinged resting state of the system is flush with the upper free end of the stamp or stamp element 9 receiving the weights or weight elements 8.

(13) FIG. 2 shows in a preferred embodiment of the invention, how the particularly cylindrical shaped balloon body 10 is housed in the cup-like guides or half-shells 11a (lower cup) and 11b (upper cup).

(14) The balloon body or balloon reservoir 10 preferably consists of a thin-walled, particularly little volume-stretchable polyurethane (PUR) having wall thicknesses ranging preferably from 5 micrometer to 20 micrometer. The balloon body 10 is preferably made from a material or PUR of Shore hardness SOA to 95A and less preferred of Shore hardness 55D to 60D, which advantageously restricts its particularly radial volume stretchability in case of a filling using typically applied or prevailing pressures of up to ca. 100 mbar and secures the conservation and self-supporting keeping of its cylindrical shape even in the gap region 12 between the cup halves (i.e. cup-like half-shells) 11a, 11b. The balloon 10 is firmly sealingly bonded (i.e. glued) with its lower end 10a to a plug-like element 15 (also referred to as lower cone 15). The plug 15 comprises a continuous bore 15a for connection of a filling hose 14. The filling hose connection or the filling hose 14 of the filling pipe is particularly bonded into the lower end of the plug 15 (or end of the bore of the plug).

(15) On its upper end 10b the balloon 10 is also firmly sealingly bonded to a plug-like element 13 (also referred to as upper cone 13). The binding plug 13 bonded into the upper end 10b particularly comes with a particularly conical shaped end, which is plugged into a corresponding bore 13a in the bottom of the upper cup 11b from the inside, and thus firmly connects-though manually detachable—the reservoir balloon 10 by means of a compression. Besides a compression of the plug 13 in the upper cup 11b the leading conical part of the plug 13 can reach through the cup 11b and can be plugged into a corresponding central bore 21a in the bottom of the fall cross or fall body 21 and thus support the connection between the fall cross 21 and the upper cup 11b.

(16) The lower balloon end 10a also comprises a particularly conical shaped plug 15, which has a central bore 15a (see above), through which the balloon 10 is filled. The conical portion of the plug 15 is inserted from the outside into a corresponding conical bore 17 of the bottom surface of the lower cup 11a with slight compression and thus connects the reservoir balloon 10 with the lower cup 11a. The largest diameter of the upper plug 13 is selected such that it can be passed through the smallest diameter of the bore 17. By means of the cones it is thus possible to lead the reservoir balloon 10 through the bottom of the lower cup 11a into the upper cup 11b, to anchor the reservoir balloon there, and subsequently, by insertion of the lower cone into the bottom of the lower cup and in case of applied pressure force, to secure the reservoir balloon 10 in its position between the two cup elements 11a, 11b. The cones allow the easy replacement of the reservoir balloon 10. In a preferred manner, the entire air or pressure-leading system of the controller consists of an integrated unit out of sealingly and fixedly interconnected elements and will also be replaced as such.

(17) To avoid a too rapid volume flow or exchange between the communicating reservoir balloon 10 and the catheter balloon 3, the fill hose 14 can also be equipped with a correspondingly small inner lumen, which acts throttling on the flow of the filling medium. A throttling effect can also be achieved by a correspondingly reduced diameter of bore 15a. Preferably, the throttling segment has an inner diameter ranging from 0.5 mm to 1.0 mm and has a length ranging from 5 mm to 10 mm.

(18) Generally, to avoid an undesirably rapid volume flow or exchange between the compartments communicating with each other, the air leading hose portions of the controller can be provided at any point with a throttling element or a lumen reduction, which limits the volume flow.

(19) FIGS. 2a and 2b show exemplary the spatial accommodation of the reservoir balloon 10 in the balloon-guiding cup elements (i.e. cup-like half-shells) 11a and 11b in more detail, wherein the reservoir balloon 10 is shown in FIG. 2a completely filled and developed in its entire cylindrical length within the cup guides 11a, 11b. The cup gap 12 thus has its maximum extent. Upon further filling beyond the balloon volume corresponding to a free, stress-free deployment of the balloon 10, the balloon wall crosses over to a gradual expansion, and the balloon wall breaks out radially (i.e. in the radial direction) in the gap region.

(20) FIG. 2b shows the balloon 10 in the state of rest, wherein the two cup halves 11a, 11b butt against each other substantially gap-free 12.

(21) The upper and lower cones 13 and 15 are here directly pressed into the respective cup halves 11a, 11b.

(22) For better visual readability of the respective outer cup contour (closed gap-free or opened with gap), the lower cup half 11a is preferably separated by a stamp-like extension 11c from the bottom of the foot unit 5, and is thus represented inside the cylinder nearly contour-closed, in a most free presentation.

(23) The indicator function of the gap 12 occurring between the reservoir balloon-guiding cup halves 11a, 11b can be supported by a particular form of the balloon-holding cup. It has been found that the gap-based readability of the pressure action in the system is facilitated by a, for example, spherical or ovoid contour of the overall cup 11a, 11b. The respective sphere or egg shape breaking open upon forming of the gap 12 is intuitively recognized and registered as deviating from the normal state by the observing eye. The recognition of the shape deviation can be supported by an appropriately aggressive choice of color for the, for example, egg-shaped cup body.

(24) Advantageously, the cup body 11a, 11b may be designed in a signal orange or yellow.

(25) The indicator function of the gap 12 is advantageously supported by a clear transparent balloon body.

(26) FIG. 3 describes, in a notably particular embodiment of the invention, how the action of weight (e.g. the weight elements 8) can be transferred in a plumb-vertical manner to the (upper) cup guide 11b and, in particular, to the reservoir balloon 10 fixed in the latter. Here, the upper cup guide 11b optionally comprises a central bore 13a into which a plug-like connection member 13 is inserted, which makes the connection of the cup member 11b to a fall cross or fall body 21 facilitating the precise plumb-vertical guiding of the force-effective weights 8.

(27) The roll guiding of the fall cross serves the precisely guided, vertical, largely frictionless guiding of the force-effective elements.

(28) The fall cross 21 preferably has an outer roll guiding facing towards the cylinder inside by means of several low-friction supported ball or wheel elements 22 (see FIG. 3a). Preferably, the cross 21 comprises four legs or recesses 22a that are particularly arranged at right angles with respect to each other as shown in FIG. 3a, wherein each leg or recess 22a comprises two roll-like elements 22, which guide the cross 21 on the inner wall (e.g. on the inside) of the cylinder 6. The fall cross 21 comprises an optional central bore hole 18, which receives a handle element 9 (also denoted as stamp or stamp element) upwardly, which serves for receiving the weight rings 8. The handle member 9 is connected to the fall cross without play, but can be well released from each other. It can be removed at any time from the cylinder upwards, and can be provided with the respectively required weights.

(29) Generally, the fall cross or body 21 may have a cylindrical shape as shown in FIG. 3a with four recesses 22a receiving the ball or wheel elements 22, wherein the regions comprising the recesses 22a may also form protrusions (e.g. legs at right angles) such that the fall cross 21 actually comprises a cross-like cross section.

(30) Alternatively, the fall cross 21 comprises an optional central through-bore hole, which, on the lower side, connects to the upper cup member 11b, and receives said handle element 9 (also denoted as stamp or stamp element) upwardly, which serves for receiving the weight rings 8.

(31) The upper cup guide 11b is thus connected to the stamp (also denoted as stamp element or handle element) 9 receiving the weights via a special element, here a so-called fall cross 21, which allows for the plumb-vertical guiding of the elements acting force-effectively on the balloon 10.

(32) In the non-loaded, gap-free state of the device 1, the tip of the stamp-like handle element 9 is flush with the surface of the lid element (or closure element) 7 closing the cylinder upwards. In case the cup halves 11a, 11b separate from each other and a gap develops between them, a corresponding exit of the tip of the shaft of the stamp 9 through the through-opening in the lid element 7 occurs, which represents a further optional function indicating the pressure effect set in the system.

(33) FIG. 4a shows as (structurally less complex) alternative to the fall cross or body 21 a simple cup-like device 23 or cup guide 23 for receiving one or a plurality of ball weights 24. The cup guide or cup-like device is optionally connected by a connecting element, for example a pin, on the lower surface to the upper balloon guiding cup. For a better or friction-reduced guiding of the ball-receiving cup 23, the latter can be alternatively applied on a fall cross as described in FIG. 3.

(34) However, in a less preferred embodiment, as shown in FIG. 4b, one may completely dispense with a cup-like guide 11a, 11b of the reservoir balloon 10. Here, the balloon 10 can be fastened through the plug 13 directly in the bottom of the ball-receiving cup 23. In order to avoid that in case of a missing cup guiding of the balloon wall portions of the balloon 10 get caught in the slit 25 between the cylinder inner wall and the ball cup outer wall thus blocking the free run of the cup 23 inside the cylinder 6, the slit 25 should be designed correspondingly wide and should amount to 1 mm for example. In the absence of a guiding of the balloon 10 by means of appropriate cup elements 11a, 11n, the readability of the pressure-indicating gap 12 can be ensured as well in this simplest embodiment, by designing the bottom of the cup 25 such that it is flush with the surface 26 of the foot unit 5 in a non-impinged state. In case the filling pressure in the balloon 10 overcomes the applied weight pressure, a readable gap 12 develops in case of increasing filling volume.

(35) FIG. 5 shows annular markings 27 and 28 of the cylinder 6, which on one hand (27) represent an optimal volume reserve in the communicating system, which is to be set, and on the other hand (28) marks a volume, which should not be exceeded, in order to avoid an upward development of the balloon 10 in the range of a complete longitudinal extent as far as possible. The ring 27 should be placed approximately 1 cm to 2 cm above the upper edge of the lower cup 11a, the ring 28, however, should be preferably spaced apart from the other ring 27 by about 3 cm to 4 cm. The remaining distance up to the complete deployment height of the balloon 10 should amount to, starting from the ring marking 28, about 2 cm to 3 cm.

(36) In FIG. 6, the entire air-guiding system of the controller 1 is shown as an exemplary unit. The balloon 10 is connected to the two cones 13 and 15 in a sealing manner, the filling line 14 is sealingly inserted into the cone 15, and is in turn connected permanently and sealingly to the valve 4. The entire illustrated unit thus allows, if necessary, the rapid change of the air-conducting system.

(37) FIG. 7 shows a particular embodiment of annular weights 8, as they may be used in combination with a stamp-shaped receiving element 9. The ring 8 has a central bore hole 31 for receiving the shaft of the stamp. Preferably, the ring comprises reduced diameters 29 (recesses) on the upper and lower side deviating from the central, largest diameter. During stacking on the stamp, this results in a slit between the respective weight rings separating the units that facilitate the countability of the units for the user. The ring may also comprise circumferential millings 30 that are filled with color, so as to allow for an easy to read color coding of the respective weight of the units.

(38) Preferably, all elements resting on the reservoir balloon in the described embodiments, with the exception of the variable weight elements, are preferably made of aluminum or PEEK, and are preferably calculated such concerning their mass that preferably a pressure-effective weight results, which when resting on the balloon body, generates a pressure of particularly 15 mbar in the latter. The weights (weight rings and balls) are preferably made of high quality or stainless steel. Each individual weight element 8, 24 is in turn preferably dimensioned such that when it is applied, a respective pressure increase of 15 mbar is established.

Example 1

(39) In the following, for the described embodiment of the fall cross base, some examples of weight and pressure calculations are shown.

(40) The aim is setting a pressure in the reservoir balloon 10 of 15 mbar in the state, in which the balloon 10 is not loaded with weights 8. Assuming a force-receiving cross-sectional area of the balloon of 907.9 mm.sup.2 (0.000908 m.sup.2), which corresponds to a cylindrical balloon diameter of 34 mm, a weight of approximately 1.41 N is required for this, which corresponds to a mass of 144 g (0.144 kg).

(41) Depending on the respective material used for the stamp 9, the fall cross 21 and the upper cup guide 11b, the mass of the components must yield 144 g in total.

(42) The ring weights 8 applied to the stamp 9 consist for example of high quality or stainless steel of grade 1.4301, with a density of 7.9 kg/m.sup.3. For causing a system pressure rise of 15 mbar in the system, a discoid weight element as shown in FIG. 7 with a diameter of 40 mm has a height of about 17 mm (taking into account a central bore hole in the stamp of 8 mm).

FURTHER EXAMPLES

(43) In another example the ring weights consist of high quality or stainless steel of grade 1.4301, with a density of 7.9 kg/m.sup.3

(44) All other parts acting on the balloon are made out of PEEK and have a density of 1.32 g/cm.sup.3.

(45) Calculation of the force action in the non-loaded state of rest (without applied weights):

(46) TABLE-US-00001 Name Density g/cm.sup.3 Volume cm.sup.3 Masse g Upper balloon guide (11b) 1.32 13.222 17.45 Upper plug (13) 1.32 3.796 5.01 Fall cross (21) 1.32 16.838 22.22 Roll (22) 1.32 0.531 5.61 Pin (connection roll/cross) 1.32 0.1414 1.49 handle (9) 1.32 9.332 12.32 Sum 43.8615 64.10

(47) The weight required to generate a pressure of 5 mbar is calculated as follows:

(48) $\begin{array}{c}{F}_g\left(5\mathrm{mbar}\right)=P\times A\\ =500\frac{N}{m^2}\times 0.00125664m^2\\ =0.628N\\ =0.628\frac{\mathrm{kgm}}{s^2}\end{array}$

(49) Mass in kg:

(50) $m=\frac{F_g}{g}=\frac{0.628N}{9.81\frac{m}{s^2}}=0.0640489\mathrm{kg}=64.04g$

(51) The upper cup-like balloon guide (11b) of Ø40 mm rests on the balloon with a force-effective circular area of 1256.64 mm.sup.2. The calculation is as follows:

(52) Balloon Guide Pressure Area:
A=π×202.sup.2 mm.sup.2=1256.64 mm.sup.2

(53) Pressure g/cm.sup.2:

(54) $p=\frac{m}{A}=\frac{64.03g}{12.5664{\mathrm{cm}}^2}=5.09\frac{g}{{\mathrm{cm}}^2}$

(55) The pressure sum generated by the PEEK-elements (without load provided by the weights) thus amounts to 5 mbar: 5.002 mbar.

(56) Calculation of the force action of the ring weights out of V2A

(57) TABLE-US-00002 Name Density g/cm.sup.3 Volume cm.sup.3 Mass g Weight ring 7.9 16.16 127.69

(58) For a weight element out of high quality or stainless steel generating 10 mbar the following required mass is calculated:

(59) $m=\left(\frac{D^2\times \pi }{4}-\frac{d^2\times \pi }{4}\right)\times h\times \rho$$\begin{array}{c}m=\left(\frac{{3.85}^2{\mathrm{cm}}^2\times \pi }{4}-\frac{{1.05}^2{\mathrm{cm}}^2\times \pi }{4}\right)\times 1.5\mathrm{cm}\times 7.9\frac{g}{{\mathrm{cm}}^2}\\ =127.69g\end{array}$$\mathrm{Pressure}g\text{/}{\mathrm{cm}}^2\text{:}p=\frac{m}{A}=\frac{127.69g}{12.5664{\mathrm{cm}}^2}=10.16\frac{g}{{\mathrm{cm}}^2}$

(60) Another example for the cup variant having ball weights

(61) By means of respectively one ball weight (22) the filling pressure in the system can be increased, respectively, by 10 mbar.

(62) Force Action in the non-loaded state of rest (without weights)

(63) TABLE-US-00003 Name Density g/cm.sup.3 Volume cm.sup.3 Mass g Cup guide (23) 1.32 35.29 46.58 Upper balloon guides 1.32 13.22 17.40 Sum 48.51 64.03

(64) Pressure g/cm.sup.2:

(65) $p=\frac{m}{A}=\frac{64.03g}{12.5664{\mathrm{cm}}^2}=5.09\frac{g}{{\mathrm{cm}}^2}$

(66) The ball weights are made out of high quality or stainless steel and shall generate a balloon or system pressure of 10 mbar by means of their weight.

(67) TABLE-US-00004 Name Density g/cm.sup.3 Volume cm.sup.3 Mass g Ball weight (24) 7.9 16.21 128.06

(68) Ball volume:

(69) $V=\frac{D^3\times \pi }{6}\mathrm{in}{\mathrm{mm}}^3$

(70) Diameter of a ball out of V2A for 10 mbar:

(71) $D=\sqrt[3]{\frac{m\times 6}{\rho \times \pi }}=\sqrt[3]{\frac{0.12806g\times 6}{7.9\frac{\mathrm{kg}}{{\mathrm{dm}}^3}\times \pi }}=0.34\mathrm{dm}=31.4\mathrm{mm}$

(72) Diameter is 31.4 mm

(73) As an alternative to the standard embodiment of the device having a foot, the controller can also be equipped with a C-shaped holding mechanism for mounting it to usual device holders in the operating room (mounting rail).