CN101966364A - Negative pressure wound treatment system capable of detecting air leakage rate - Google Patents

Abstract

The invention discloses a negative pressure wound treatment system capable of detecting an air leakage rate, which comprises a liquid-collecting bottle, negative pressure wound treatment equipment, a wound kit and an exudate volume detection unit, wherein the liquid-collecting bottle collects wound exudates; the negative pressure wound treatment equipment consists of a negative pressure source and a controller; the wound kit fills and seals a wound and is communicated with the liquid-collecting bottle through a connecting conduit; the exudate volume detection unit detects the volume of the wound exudates in the liquid-collecting bottle; and the controller calculates the air leakage rate according to the volume of the wound exudates, environmental temperature and a negative pressure variable quantity of the negative pressure source. The negative pressure wound treatment system capable of detecting the air leakage rate can measure the current air leakage rate so that a medical worker or a user can intuitively know the air leakage degree, therefore, related connecting parts are checked and the air leakage degree is reduced.

Description

Can detect the negative pressure wound treating system of leak rate

Technical field

The present invention relates to the negative pressure wound therapy equipment technical field, relate in particular to a kind of negative pressure wound treating system that detects leak rate.

Background technology

Negative pressure wound therapy equipment, the U.S. is called Negative_Pressure_Wound_Therapy_Devices, abbreviates NPWT as, and its principle promotes the healing of wound for by the wound being applied negative pressure.According to clinical show of the U.S. over nearly 10 years, this equipment has good healing effect to the treatment of wounds of various acute and chronics.

Usually, the negative pressure wound treating system container (being called this container here is liquid-collecting bottle) that comprises negative pressure wound therapy equipment, wound external member and be used for collecting the wound transudate.Wherein, the wound external member is used for wound closure, makes negative pressure space.Negative pressure wound therapy equipment is used to create needed wound negative pressure, and negative pressure wound therapy equipment by a negative pressure source, is formed with a controller.Referring to Fig. 1, shown in the figure a kind of common negative pressure wound treating system.In the frame of broken lines is negative pressurewound therapy equipment 8; 1 is human body wound circumference skin histology;Wound implant 2 covers the human body wound;Wound closure 3 is set abovewound implant 2, wound is sealed,wound implant 2 is connected on the liquid-collectingbottle 5 by connection tube 4, thereby will be directed to from the transudate of wound in the liquid-collectingbottle 5, collect from the transudate of wound by liquid-collectingbottle 5, the other end of liquid-collectingbottle 5 is connected withnegative pressure source 6, provides negative pressure bynegative pressure source 6, provides power for wound fluid flow to liquid-collectingbottle 5;Negative pressure source 6 connects acontroller 7, realizes control by 7 pairs of negative pressure sources ofcontroller 6.

Because negative pressure treatment equipment, liquid-collecting bottle, wound are connected by gas circuit, the slit of junction and the gas leakage that causes thus are unavoidable.When gas leakage when serious, equipment even can not be evacuated to the negative pressure value of setting just needs the equipment alarm prompting this moment, makes negative pressure wound treating system user or medical personnel can in time check failure cause, and gets rid of fault.When but the still very high equipment of leak rate still can be evacuated to the setting negative pressure value, the startup of equipment air pump this moment blanking time can be very short, air pump starts frequent, power consumption is big for system, air pump reduces service life, can make also that thus negative pressure treatment equipment noise is bigger, influences patient's normal rest, nursing.

Summary of the invention

The objective of the invention is to, a kind of negative pressure wound treating system that detects leak rate is provided, can detect leak rate, make user or medical personnel can understand the gas leakage degree intuitively.

For solving the problems of the technologies described above, a kind of negative pressure wound treating system that detects leak rate of the present invention comprises:

Liquid-collecting bottle is collected wound fluid;

Negative pressure wound therapy equipment is made up of negative pressure source and controller;

The wound external member is filled wound and wound closure, is communicated with liquid-collecting bottle by connection tube;

Also comprise:

Transudate volume detecting unit, the volume of wound fluid in the detection liquid-collecting bottle;

Described controller calculates leak rate according to the negative pressure variation amount of wound fluid volume, ambient temperature and negative pressure source.

Preferably, described controller also comprises display interface, shows the numerical value of described leak rate or the figure of sign leak rate size.

Preferably, described display interface is LED interface or LCD interface.

Preferably, also comprise alarm device, described controller is compared the leak rate that computing draws with preset threshold value, judge whether to send alarm signal, when alarm device receives alarm signal, reports to the police.

Preferably, the leak rate that computing draws is during greater than preset threshold value, and controller sends alarm signal, and alarm device is reported to the police.

Preferably, described alarm device is sounded and/or light when reporting to the police.

Preferably, also comprise temperature sensor, obtain ambient temperature.

Preferably, described wound fluid volume detection module comprises:

Transmitter unit is to liquid-collecting bottle launching electromagnetic wave or acoustic signals;

Receiving element receives through liquid-collecting bottle reflection or refractive electromagnetic wave or acoustic signals;

Detect control unit, whether receive electromagnetic wave or acoustic signals according to receiving element and judge that the detection module position locates whether to have wound fluid.

Preferably, described wound fluid volume detection module is a plurality of, and the distance identical along the longitudinal separation of described liquid-collecting bottle is provided with.

Preferably, described wound fluid volume detection module is arranged on the drive mechanism, and described drive mechanism connects a driving mechanism.

The negative pressure wound treating system that detects leak rate of the present invention because wound fluid volume detecting unit is set, detects the volume of wound fluid in the liquid-collecting bottle; Described controller calculates leak rate according to transudate volume and ambient temperature, and therefore, the present invention can directly detect the leak rate of system, makes things convenient for medical personnel or other user to understand the gas leakage degree intuitively.

Further, also be provided with display unit, show the numerical value of leak rate or the figure of sign leak rate size, use convenient, directly perceived.

Further, also be provided with alarm device, in leak rate during greater than default preset threshold value, alarm device is reported to the police, so that in time remind medical personnel, medical personnel are in time checked relevant connection portion, reducing leak rate, and then avoid energy waste, improve air pump service life, avoid influencing patient because of gas leakage produces noise.

Description of drawings

Fig. 1 is the structural representation of existing negative pressure wound treating system;

Fig. 2 is the sketch map of interior gas volume of liquid-collecting bottle and wound fluid volume;

Fig. 3 is the structural representation that the present invention can detect the negative pressure wound treating system embodiment one of leak rate;

Fig. 4 is the pictorial display sketch map of leak rate;

Fig. 5 is the light path sketch map of A part among Fig. 1;

Fig. 6 is the light path principle figure when the liquid-collecting bottle somewhere does not have transudate among the embodiment one;

Fig. 7 is the light path principle figure when there is transparent transudate in the liquid-collecting bottle somewhere among the embodiment one;

Fig. 8 is the sketch map that cooperates that the present invention can detect the long-pending detection module of wound liquid body exudate and drive mechanism, driving mechanism among the negative pressure wound treating system embodiment two of leak rate.

Among the figure, relevant Reference numeral is as follows:

The 1-wound, 2-wound implant, 3-wound closure, the 4-connection tube, 5-liquid-collecting bottle, 6-negative pressure source, the 7-controller, 8-negative pressure wound therapy equipment, 9-wound fluid volume detection module, the 91-transmitter unit, 92-receiving element, 10-screw mandrel, the 11-motor, the 12-display interface, 13-alarm device, 14-transudate.

The specific embodiment

The principle that the application utilizes is as follows:

The gas flow (molal quantity is made as n) that sealed container is interior, pressure P, volume V, the pass between temperature (Kelvin) T is: PV=nRT, wherein, R is a constant.

This formula is very stable near room temperature, and the normal working temperature scope of negative pressure wound therapy equipment is usually between 0-40 degree centigrade, and promptly 273 Kelvins are between 313 Kelvins.That is to say that in this temperature range, this formula is very stable.Simultaneously, when working in this temperature range, gas temperature and the residing ambient temperature of negative pressure treatment equipment in the enclosed space can be thought unanimity.Wherein, ambient temperature can record immediately, during certain, under the certain environment, also can be set at a constant.

Gas volume by the negative pressure treatment system is controlled is respectively:

Gas volume V in the liquid-collecting bottle₁

The gas volume V of gas volume and wound in the trachea of liquid-collecting bottle and wound₂

Reach the gas volume V between negative pressure treatment equipment and liquid-collecting bottle connection tube in the negative pressure treatment equipment₃,

Then the cumulative volume V in the negative pressure treatment system is:

V＝V₁+V₂+V₃

Wherein, V₂With V₃Very stable comparatively speaking, this is because after a negative pressure wound therapy equipment is finalized, V₂With V₃All be customized specification, itself and can be definite value.Therefore, has only V₁Volume can change along with the wound fluid amount in the liquid-collecting bottle.

The volume of setting liquid-collecting bottle is V₅, the volume of transudate is V in the liquid-collecting bottle₄, then gas volume is in the liquid-collecting bottle: V₁=V₅-V₄, referring to Fig. 2;

Wherein, for the liquid-collecting bottle of customization, its volume V₅Be definite value, so V₁With V₄Increase and reduce.

A certain spatial leak rate is weighed with the minimizing of the number of moles of gas of this space in certain time slot.

Suppose that in the t of time slot, the negative pressure of negative pressure wound treating system is from P₁(corresponding molal quantity n₁, P₁Be absolute value) drop to P₂(corresponding molal quantity n₂, P₂Be absolute value), represent that the gas content in this system lock space has reduced N:

N＝n₁-n₂；

Because:

$n=\frac{\mathrm{PV}}{\mathrm{RT}};$

${\mathrm{<figure-callout\; label="n"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">n</figure-callout>}}_1=\frac{P_1(V_5-V_4+{\mathrm{<figure-callout\; label="V"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+V_3)}{\mathrm{RT}};$

${\mathrm{<figure-callout\; label="n"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">n</figure-callout>}}_2=\frac{P_2(V_5-V_4+{\mathrm{<figure-callout\; label="V"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+V_3)}{\mathrm{RT}};$

$N=\frac{(P_1-P_2)(V_5-V_4+{\mathrm{<figure-callout\; label="V"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+V_3)}{\mathrm{RT}};$

The note leak rate is L, and by above-mentioned publicity, then L is:

L＝N/t

$L=\frac{(P_1-P_2)(V_5-V_4+{\mathrm{<figure-callout\; label="V"\; filenames="HSA00000259292600011.png"\; state="\{\{state\}\}">V</figure-callout>}}_2+V_3)}{\mathrm{RTt}}.$

Therefore, leak rate L can be quantized fully, and from then on formula as long as measure the volume of wound fluid in the liquid-collecting bottle, can record leak rate as can be seen.

Based on the aforementioned calculation formula, below in conjunction with accompanying drawing, the present invention is described in detail by specific embodiment:

Embodiment one

The leak rate threshold value of acquiescence can be set according to the situation of reality, and when the leak rate that calculates was higher than this threshold value, whether prompting user or medical personnel's check system have connected the problem that may relate to gas leakage such as insufficient.

Referring to Fig. 3, the negative pressure wound treating system of the detected leak rate in the present embodiment comprises:

Liquid-collectingbottle 5 is used to collect wound fluid;

Negative pressure woundtherapy equipment 8 comprisesnegative pressure source 6 andcontroller 7;

The wound external member is used to fill wound and wound closure, comprises woundimplant 2, woundclosure 3, and woundimplant 2 is communicated with liquid-collectingbottle 5 by connection tube 4;

On the sidewall of liquid-collectingbottle 5, also be provided with four wound fluidvolume detection modules 9;

The pick off (not shown) is obtained ambient temperature;

Thiscontroller 7 calculates corresponding leak rate according to the negative pressure variation amount of transudate volume, ambient temperature and negative pressure source.

Controller 7 connects adisplay interface 12, thisdisplay interface 12 can directly show the numerical value of leak rate, as shown in Figure 4, also can show the figure of expression leak rate size, wherein B represents the size of leak rate threshold value, and C represents the size of leak rate instantly, therefore, can can know whether greater than the residing position of B how many leak rates is approximately from C present position instantly, whether surpass threshold value.

Wherein, display interface is the LED display interface.Certainly, also can select other display interfaces for use, as the LCD interface.

Wherein,controller 7 also connects analarm device 13, controller compares leak rate value and the preset threshold value that computing draws, when greater than threshold value, send alarm signal,alarm device 13 is sounded and is warned light, with timely prompting medical personnel or user, impel it to check relevant connection portion, reduce leak rate.

Wherein, each wound fluidvolume detection module 9 comprises:

Transmitter unit 91 to liquid-collectingbottle 5 launching electromagnetic waves or ultrasonic signal, is arranged on a side of liquid-collectingbottle 5;

Receivingelement 92, receive through liquid-collectingbottle 5 refractive electromagnetic wave or ultrasonic signals, relatively be arranged on the opposite side of liquid-collectingbottle 5 withtransmitter unit 91, make it when the position does not have wound fluid, just to receive herein through penetrating refractive electromagnetic wave or ultrasonic signal at liquid-collectingbottle 5.

Detect control unit, whether receive electromagnetic wave or ultrasonic signal is judged, if not, judge that then there is wound fluid at place, wound fluid volume detection module position according to receiving element.

Wherein, the electromagnetic wave that adopts in the present embodiment is an infrared ray, as other embodiment, also can adopt visible light, ultraviolet, laser or other electromagnetic signals, can adopt ultrasound wave, infrasonic wave or other acoustic signals.

Wherein, four gears that characterize the wound fluid liquid level are set in the liquid-collectingbottle 5, and make each gear corresponding to a transudatevolume detection module 9, whether receivingelement 92 according to this transudatevolume detection module 9 receives infrared signal, whether judge has transudate herein, can judge wound fluid liquid level in the liquid-collectingbottle 5 by receivingelement 92 quantity that can receive infrared signal then, in conjunction with the floor space of liquid-collecting bottle, can calculate the transudate volume in the liquid-collecting bottle again.

Below the operation principle of the long-pendingdetection module 9 of wound liquid body exudate among the present invention is described.

Referring to Fig. 5,transmitter unit 91 sends infrared ray S1,sidewall 51 1 sides of process liquid-collectingbottle 5 penetrate refraction and enter liquid-collectingbottle 5interior zones 52, and then penetrate fromsidewall 51 opposite sides of liquid-collectingbottle 5, receivingelement 92 receives and penetrates the infrared ray S1 that refraction is come, and another part Infrared is through being reflected into reflection ray S2.

Referring to Fig. 6, the light path sketch map when Fig. 6 does not have wound fluid for relevant position in the liquid-collecting bottle, the infrared ray light path during below to the no wound fluid in 5 these places of the liquid-collecting bottle betweentransmitter unit 91, the receivingelement 92 is further analyzed:

Infrared ray is mapped to liquid-collectingbottle 5 outer surface of outer cover, injects liquid-collectingbottle 5 shells, is mapped to liquid-collectingbottle 5 inner surface of outer cover if α, beta, gamma, θ are respectively, infrared ray and normal angle when injecting liquid-collectingbottle 5 inner chambers.Inject the point of liquid-collectingbottle 5 outer surface of outer cover and penetrate point respectively and the angle that forms between the liquid-collectingbottle 5 section central point lines if δ is an infrared ray from inner surface.If liquid-collectingbottle 5 radiuses are R, wall thickness is h.

If liquid-collectingbottle 5 shell refractive indexs are n1, refractive index is about 1 in the air, by the law of refraction:

Sin α=n1sin β ≈ n1sin γ=sin θ, then α ≈ θ.In like manner can get θ '=α '.θ and θ ' are isosceles triangle two base angles, so θ=θ ', then α=θ=θ '=α '.

Thus, angle ε is mainly determined by the deflection of infrared ray at 2 circular arc normals of ejaculation point of injecting a little and penetrating from inner surface of liquid-collectingbottle 5 outer surface of outer cover between the infrared ray S13 that then injects the infrared ray S11 of liquid-collectingbottle 5 outer surface of outer cover and penetrate from inner surface, can be similar to writing:

ε＝δ≈h?tanβ/R＝h/R?tan[arcsinα/n1]

The angle of injecting the infrared ray S12 of liquid-collectingbottle 5 inner surfacies and penetrating between the infrared ray S13 of liquid-collectingbottle 5 outer surface of outer cover also is δ.Angle should be 2 ε=2 δ ≈ 2h/Rtan (arcsin α/n1) between infrared ray S11 and infrared ray S13.

When h＜＜R, δ can ignore, the infrared ray S11 that injects liquid-collectingbottle 5 outer surface of outer cover is substantially parallel with the infrared ray S13 that penetrates liquid-collectingbottle 5 outer surface of outer cover.

Therefore, as shown in Figure 6, receivingelement 92 is arranged on the same horizontal line withtransmitter unit 91, and receiving element can receive through refractive infrared ray, therefore, judges and does not have wound fluid herein.

In like manner, the infrared ray light path in the time of can transparent wound fluid being arranged to 5 these places of the liquid-collecting bottle betweentransmitter unit 91, the receivingelement 92 is further analyzed, referring to Fig. 7, and the index path when Fig. 7 is equipped with wound fluid for corresponding positions in the liquid-collecting bottle:

If the transudate refractive index is n2, then by the law of refraction:

sinα＝n2sinθ＝n2sinθ’＝sinα’。

Angle ε between the infrared ray S12 that injects the infrared ray S11 of liquid-collectingbottle 5 outer surface of outer cover and penetrate from inner surface:

ε＝(α-θ)+δ＝[α-arcsin(sinα/n2)]+δ≈[α-arcsin(sinα/n2)]+h/Rtan(arcsinα/n1)；

When h＜＜R, δ can ignore, angle ε: ε ≈ α-arcsin (sin α/n2);

Angle should be between infrared ray S11 and infrared ray S13: and 2 ε ≈ 2[α-arcsin (sin α/n2)];

Example: when α=30 ° are π/6 radians, and hypothesis transudate refractive index and water are near, are n2=1.33.Then angle should be between infrared ray S11 and infrared ray S13: 2 ε ≈, 0.276 radian, promptly 15.8 °.

Be that angle can produce about 15.8 ° variation between incident, emergent ray when transudate being arranged herein in the liquid-collecting bottle 5.Therefore, referring to Fig. 7, receivingelement 92 does not receive Infrared, and therefore, can judge has wound fluid herein in the liquid-collectingbottle 5.

Utilize this characteristic, position by receivingelement 92 is provided with, make it under liquid-collectingbottle 5 no transudate situations, to receive emergent ray just, can't receive this emergent ray and have at liquid-collectingbottle 5 under the situation of wound fluid, can judge liquid position in the liquid-collectingbottle 5, and then calculate liquid volume in the liquid-collectingbottle 5.

Embodiment two

The difference of present embodiment and embodiment one is:

1, a wound fluidvolume detection module 9 only is set, transmitter unit and receiving element collection are located at together, referring to Fig. 8, wound fluidvolume detection module 9 is enclosed within on thevertical screw mandrel 10 that extends of a centrage, and screwmandrel 10 centrages are parallel with liquid-collectingbottle 5 above-below directions; Preferably, wound fluidvolume detection module 9 is suffered restraints onscrew mandrel 10 centrage circumferential direction, only can on screwmandrel 10 centerline directions, move; One end ofscrew mandrel 10 is connected withmotor 11, and under the driving ofmotor 11,screw mandrel 10 moves up and down alongscrew mandrel 10 centrages thereby drive woundfluid volume module 9 around its centrage rotation, whether liquid-collectingbottle 5 relevant positions is had wound fluid detect.

Wherein,screw mandrel 10 also can be substituted as in: gear train, belt, the skin wheel any by other drive mechanisms; As long as wound fluidvolume detection module 9 can be moved in vertical direction with respect to liquid-collectingbottle 5, just can realize detecting the purpose of liquid-collectingbottle 5 relevant position amount of liquid.

Whenmotor 11 work, drive wound fluidvolume detection module 9 byscrew mandrel 10 and move up and down.Receiving element is in the time and can not detecting between infrared signal redirect, then can determine that the present position is corresponding to liquid level at this moment by wound fluidvolume detection module 9, and then, determine the liquid level of liquid-collectingbottle 5, thereby calculate the amount of wound fluids in the liquid-collectingbottle 5 according to the stroke of motor.

2, in the present embodiment temperature sensor is set not, directly gets the average ambient temperature value in the certain hour.

In the various embodiments described above, in liquid-collecting bottle 5, during the position no liquid at wound fluid volume detection module 9 places, make receiving element 92 can receive electromagnetic wave signal or acoustic signals, when there is liquid the position at wound fluid volume detection module 9 places, make receiving element 92 can not receive electromagnetic wave signal or acoustic signals; And then when receiving element 92 did not receive electromagnetic wave signal or acoustic signals, the position of judging wound fluid volume detection module 9 places was to stagnate liquid is arranged.According to foregoing description, also can determine that the position at wound fluid volume detection module 9 places is to stagnate liquid is arranged with opposite mode.Such as, when electromagnetic wave signal or acoustic signals can pass liquid-collecting bottle 5 and liquid, in the time of can liquid being arranged in the position at wound fluid volume detection module 9 places, make receiving element 92 can receive electromagnetic wave signal or acoustic signals, when the no liquid of the position at wound fluid volume detection module 9 places, make receiving element 92 can not receive electromagnetic wave signal or acoustic signals, whether receive electromagnetic wave signal or acoustic signals according to receiving element 92 again, the position of judging wound fluid volume detection module 9 places is to stagnate liquid is arranged, thereby realizes detecting the purpose of amount of liquid in the liquid-collecting bottle 5.In addition, difference that can also be strong and weak according to the signal of electromagnetic wave signal that receives or acoustic signals, the position of judging wound fluid volume detection module 9 places is to stagnate liquid is arranged, or the like.

Only be preferred implementation of the present invention below, should be pointed out that above-mentioned preferred implementation should not be considered as limitation of the present invention, protection scope of the present invention should be as the criterion with the determined scope of claim.For those skilled in the art, without departing from the spirit and scope of the present invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (10)

1. negative pressure wound treating system that can detect leak rate comprises:

Liquid-collecting bottle is collected wound fluid;

Negative pressure wound therapy equipment is made up of negative pressure source and controller;

The wound external member is filled wound and wound closure, is communicated with liquid-collecting bottle by connection tube;

It is characterized in that, also comprise:

Wound fluid volume detecting unit, the volume of wound fluid in the detection liquid-collecting bottle;

Described controller calculates leak rate according to the negative pressure variation amount of wound fluid volume, ambient temperature and negative pressure source.

2. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that described controller also comprises display interface, shows the numerical value of described leak rate or the figure of sign leak rate size.

3. the negative pressure wound treating system that detects leak rate as claimed in claim 2 is characterized in that, described display interface is LED interface or LCD interface.

4. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that, also comprises alarm device, described controller is compared the leak rate that computing draws with preset threshold value, judge whether to send alarm signal, when alarm device receives alarm signal, report to the police.

5. the negative pressure wound treating system that detects leak rate as claimed in claim 4 is characterized in that, the leak rate that computing draws is during greater than preset threshold value, and controller sends alarm signal, and alarm device is reported to the police.

6. the negative pressure wound treating system that detects leak rate as claimed in claim 4 is characterized in that, described alarm device is sounded and/or light when reporting to the police.

7. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that, also comprises temperature sensor, obtains ambient temperature.

8. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that, described wound fluid volume detection module comprises:

Transmitter unit is to liquid-collecting bottle launching electromagnetic wave or acoustic signals;

Receiving element receives through liquid-collecting bottle reflection or refractive electromagnetic wave or acoustic signals;

Detect control unit, whether receive electromagnetic wave or acoustic signals according to receiving element and judge that the detection module position locates whether to have wound fluid.

9. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that, described wound fluid volume detection module is a plurality of, and the distance identical along the longitudinal separation of described liquid-collecting bottle is provided with.

10. the negative pressure wound treating system that detects leak rate as claimed in claim 1 is characterized in that, described wound fluid volume detection module is arranged on the drive mechanism, and described drive mechanism connects a driving mechanism.

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