MX2009005290A - Flow controller. - Google Patents

Abstract

A device for controlling the rate of flow of a liquid in a flexible tube comprising two opposed surfaces between which the tube is received in use wherein the surfaces are elongated in the direction of flow of the liquid in the tube and are either parallel to one another or arranged so that in use the included angle does not exceed 40° DEG, and means for varying the distance between the surfaces so as to compress the tube between them by the desired amount.

Description

FLOW CONTROL COOLER The invention relates to a device for controlling the flow velocity of a liquid in a flexible tube. More specifically, this invention relates to a device for controlling the flow rate of an enteral nutritional liquid composition through the tube that is used to deliver the composition to the patient.

Due to a variety of diseases, injuries and complications, patients may not be able to obtain the necessary nutrition by ingesting food through the mouth, p. ex. , eating the food. Therefore, it is known to provide clinical nutrition both enterally and parenterally. A conventional means of providing that nutrition enterally is through the use of a feeding tube connected at one end with a supply or a liquid nutrition source and with the other end with a nasogastric feeding tube or a percutaneous endoscopic gastrostomy tube. of the patient.

It will be understood that it is necessary to control the flow velocity of the enteral composition through the tube and therefore towards the patient. In the extreme case of the free flow, the patient can literally literally drown in the fluid and in the extreme case of too low a flow velocity, the patient can be severely malnourished. Between these two extremes, it is usually desired to administer the composition at a particular flow rate taking into account the properties of the composition being administered and the needs of the patient. Typical flow rates are between 100 and 300 ml / hr although occasionally flow rates as low as 50 ml / hr may be required.

The nutritional composition can be administered with the help of a pump or under the action of gravity. When a pump is used, the flow rate can be adjusted precisely and medical care personnel can rely on the fact that once the desired flow rate has been established, it will remain until all the feeding to the patient has been delivered. However, the use of a pump adds considerably to costs and therefore pumps are only used when absolutely necessary, for example, with viscous compositions that would otherwise not achieve acceptable flow rates, or when clinically necessary precision.

However, even for feeds that can be administered under the action of gravity, it is usually necessary to control the flow rate. To accomplish this in the absence of a pump, a roller clamp is usually provided with the feed tube. Many different designs of roller clamps are known, for example from US Patent Nos. 3984081, 4,919,389 and German Patent Application No. 19621910A1. Essentially, these devices comprise an elongated frame that receives the feeding tube and a circular cross-section member mounted on the frame so that it can move up and down the length of the frame whereby the curved surface of the member with cross section Circular transverse compresses the tube to the desired degree. This reduces the cross-sectional area of the tube available for flow and therefore reduces the flow velocity.

The tubes for feeding are generally made of soft plastic materials, such as PVC. In uncompressed state, the tubes generally have a circular cross section with an internal diameter typically of the order of 3 to 4.5 mm. When compressed by a roller clamp, the lumen of the tube is strangulated and generally assumes a cross section in the form of a kidney. The cross-sectional area of the tube available for flow is reduced as desired but, over time, the plastic materials from which the tube is made begin to compress and deform by creep in the areas under stress. In other words, the tube material "deforms" around the point where it is compressed by the roller clamp and the tube generally assumes a U-shaped cross section at the compression point. Over time, this reduces the cross-sectional area available for flow and therefore reduces the flow rate even when the adjustment of the roller clamp has not changed. In addition, some dimensions of the lumen approach the approximate value of 0.5 mm, which is of the same order of magnitude of components such as dietary fibers that are often found in nutritional compositions. It will be appreciated that this carries the risk of nucleation of these particles and finally to the total blockage of the tube at the point of compression.

In practice, with foods that contain fibers and other large particles, blockage can occur approximately once every hour. Each time the tube is blocked, the nurse must open the roller clamp to release the obstruction and then readjust the clamp of roller, which results in a considerable loss of time as well as discomfort for both the patient and the nurse.

Therefore, there is a need to provide an alternative construction for a flow controller that does not have these disadvantages.

BRIEF DESCRIPTION OF THE INVENTION The present inventors have discovered, surprisingly, that if the feeding tube is compressed by generally parallel opposite surfaces, each of which is elongated in the direction of flow, the tube can be compressed in such a way that the problems of deformation by creep are minimized, and a flow rate that is stable for several hours can be achieved, and flow rates as low as 50 ml / hr can be achieved with minimal risk of blockages.

Accordingly, the present invention provides a device for controlling the flow velocity of a liquid in a flexible tube, comprising two opposing surfaces between which the tube is received on the use, where the surfaces are elongated in the direction of liquid flow in the tube and either are parallel to each other, or are arranged so that, in use, the included angle does not exceed 40 °, and means for varying the distance between the surfaces so that the tube is compressed between them by the desired amount.

The invention also extends to an enteral feeding device comprising a flexible tube and a device for controlling the flow rate of a liquid in the tube, where the device comprises two opposite surfaces between which the tube is received, surfaces that are elongated in the direction of liquid flow in the tube and either are parallel to each other, or are arranged so that, in use, the included angle does not exceed 40 °, and means for varying the distance between the surfaces, so that the tube is compressed between them by the desired amount.

Without wishing to be tied to the theory, the inventors believe that by using a device according to the invention, the geometry that is presented to the liquid, as it approaches and passes through the part of the tube compressed by the device, is such that the liquid finds a cross-section reduced in shape smooth, which therefore allows the friction to slow down the liquid. In other words, contrary to what happens with the conventional roller clamp described above, the liquid does not find any sharp corners that could act as nucleation sites for the particles or fibers as they approach and pass through the part of the tube compressed by the device.

Preferably, the length of the surfaces in contact with the tube in use is at least five times greater than the internal diameter of the tube.

Preferably, the tube includes a portion made of a highly elastic material with a low viscoelastic response such as silicone or a synthetic silicone replacement material, and that portion of the feeding tube is received within the flow controller in use.

If the opposite surfaces are not parallel, the included angle preferably does not exceed 35 °, more preferably 26 °, when the device is in use.

The opposite surfaces are generally flat.

FIGURES Figures 1 and 2 show respectively, in perspective view and in cross-sectional view, a first representation of the flow controller according to the invention; Figures 3 and 4 show respectively, in perspective view and in cross-sectional view, a second representation of the flow controller according to the invention.

DETAILED DESCRIPTION OF THE INVENTION In the present specification, the following words give a definition that must be taken into account when the description, examples and claims are read and interpreted.

"Elongate in the direction of liquid flow in the tube": the dimension of the surface extending in the direction of the flow of liquid in the tube is larger than the dimension extending transverse to the direction of liquid flow. "generally planar" means that those portions of the opposing surfaces which contact the tube in use are flat, but does not exclude the presence of minor imperfections or the presence of, for example, a channel with a radius of curvature of the same order of magnitude as the radius of the tube to be used as a guide for the tube.

"Included angle" means the angle between the opposing surfaces when the device is in use in the event that the opposite surfaces are not parallel.

As mentioned above, preferably the length of the opposing surfaces in contact with the tube in use is at least five times greater than the internal diameter of the tube. Tubes that are used for enteral feeding typically have an internal diameter of between 3 and 4.5 mm, therefore the length of the opposing flat surfaces in contact with the tube when the device is in use is preferably at least 15 mm, more preferably at least 25 mm and most preferably, between 40 and 45 mm.

To further reduce the risk of blockage of the tube in use, this preferably includes at least a portion made of an elastic material such as silicone or a silicone replacement synthetic material such as the DEHP-free DINCH, supplied by Action Technology. In use, this portion is received within the flow controller.

In one embodiment, the opposing surfaces are hinged along a long edge and the means for varying the distance therebetween comprises a threaded bolt for screwing attached to the opposite long edge of a surface and adapted to pass through an opening in the opposite long edge of the other surface, and a nut that can be screwed into the bolt to reduce the distance between the surfaces.

Alternatively, each of the opposing surfaces may be provided with an opening on the long edge opposite the joint and the means for varying the distance therebetween may comprise a threaded bolt for double-ended screwing which is provided with a fixed nut between the threads of screw so that the threaded ends to screw the bolt can be received in the openings and the bolt can be rotated using the fixed nut to vary the distance between the surfaces.

In another embodiment, the device comprises a cylindrical frame with a cavity running along its entire length, of rectangular cross section, cross section that increases linearly from one end to the other, and an insert of rectangular cross section that similarly, and with triangular longitudinal section, it increases linearly from one end to the other. The insert is adapted to be received in the cavity whereby the opposite surfaces are constituted by a surface of the cavity and a parallel surface of the insert. The means for varying the distance between the opposing surfaces comprises a collar with which the insert is mounted so that it can be inserted into the cavity and moved along the length of the cavity by the movement of the collar.

Preferably, in this case the end of the frame from which the insert is inserted into the cavity is provided with a screw thread, the collar is provided with a reciprocating screw thread and the insert is mounted on the collar so that it can rotate in relation to it, whereby the insert can be moved along the length of the cavity by the coupling of the screw threads and the rotation of the collar with respect to the frame.

The invention will now be illustrated with reference to the drawings.

Figures 1 and 2 show respectively, in a perspective view and a cross-sectional view, a representation of a flow controller (10) according to the invention. The flow controller comprises two generally planar opposing surfaces (11 and 12) arranged with a variable angle included therebetween. The surfaces (11 and 12) are joined along an edge by a joint (13) and connected at their opposite edges by a threaded rod (14) with double end that is provided with the adjustment means (15). The screw (14) is received in the threaded openings in each of the surfaces (11 and 12) so that the adjustment means (15) can be rotated to vary the angle included between the surfaces when moving the surfaces (11 and 12). 12) approaching them or moving them away from each other. The surfaces (11 and 12) are provided with the guides (16) that receive the feed tube (17). The flow controller also includes at one end an ergonomically designed fastening portion (18) to assist the nurse or other caregiver in efficiently managing the controller. flow.

In use, the flow controller is supplied preassembled around the tube. The nurse or other caregiver will connect the tube to the food to be administered and check the flow rate by counting the number of drops that pass through the tube drip tube at a given time, and adjust the flow rate to the desired value by turning the adjustment means (15) to increase or decrease the degree of compression of the tube accordingly. In the position shown in Figure 2, the adjustment means has been rotated so that the surfaces (11 and 12) hold the tube (17) without compressing it and the angle a is 26 ° for a tube with a diameter 3 mm internal It will be appreciated that the flow controller may be closed to a point where there is no flow through the tube, which may be convenient, for example, when the caregiver is changing the supply of the food to be administered. In this case, the angle a would be 9 or for a tube with an internal diameter of 3 mm.

In a variation of this representation (I do not know shows), the means for varying the angle included between the opposing flat surfaces may comprise a single-ended threaded rod on the free long edge of a surface and adapted to pass through an opening in the long edge of the opposite surface and a nut that will be screwed up and down the free end of the threaded rod to vary the distance between the surfaces.

Figures 3 and 4 show respectively, in perspective and in cross-sectional view, a second representation of a flow controller (20) according to the invention, having a generally cylindrical frame (21) provided at one end ( 22) with a screw thread (23). A cavity (24) of variable rectangular cross section runs along the length of the frame. The cross section of this cavity increases at a constant angle along its length, the distance between the roof and the base being the maximum at the end (22) and the minimum at the other end (25). A longitudinally extending guide channel (not shown) is provided in the frame (21) and connects the cavity (24) with the outside.

An insert (30) with a cross section Rectangular which similarly varies linearly from one end to the other is slidably received in the cavity (24) of the cylindrical frame (21). The insert comprises two opposite surfaces arranged so that the included angle between them is the same as the included angle between the ceiling and the base of the cavity (24). The insert is provided at its major cross-section end with a neck projecting through the guide channel and ending in a spigot (27). Stoppers (not shown) are provided at each end of the cavity (24), so that the insert (30) is captured within the cylindrical frame (21). It can be seen that the roof of the cavity (24) and the upper surface of the insert form opposite parallel surfaces, the distance between which can be increased or decreased by moving the insert into and out of the cavity.

As in the representation of Figures 1 and 2, in use the flow controller is already provided assembled around the tube (26) (Figure 3), with the insert (30) captured inside the cylindrical frame (21) and the tang (27) located in a threaded collar (31), so that the rotation of the collar (31) around the screw thread (23) slides the insert (30) in and out of the cavity (24) to compress he feeding tube by the desired amount between the upper surface of the insert and the ceiling of the cavity. As with the representation of Figures 1 and 2, the nurse or other caregiver will connect the tube to the feeding to be administered, check the flow rate by counting the number of drops that pass through the drip channel, and adjust the flow velocity to the desired value, in this case by turning the collar (31) to move the insert (30) in or out of the cavity (24) to respectively increase or decrease the degree of compression of the tube accordingly .

Furthermore, as in the representation of Figures 1 and 2, the flow controller of Figures 3 and 4 also includes at one end ergonomic fasteners (32) for the fingers.

In addition, as in the representation shown in Figures 1 and 2, the insert can be slid into the cavity so that the tube is compressed to the extent that the flow is completely interrupted.

Claims (13)

1. CLAIMS 1. Device for controlling the flow velocity of a liquid in a flexible tube, comprising two opposite surfaces between which the tube is received in use, where the surfaces are elongated in the direction of flow of the liquid in the tube and, or are parallel to each other, or arranged so that, in use, the included angle does not exceed 40 °, and means for varying the distance between the surfaces so that they compress the tube therebetween by the desired amount. Device according to claim 1, characterized in that the included angle does not exceed 35 °. Device according to claim 1 or 2, characterized in that the included angle does not exceed 26 °. Device according to any one of the preceding claims, characterized in that the length of the opposing surfaces in contact with the tube in use is at least five times greater than the internal diameter of the tube. Device according to any one of the preceding claims, characterized in that the opposite surfaces are articulated along a long edge and the means for reducing the distance between them comprises a single-ended threaded rod. mounted on the free long edge of a surface and adapted to pass through an opening in the long free edge of the other surface and a nut that can be screwed up and down the free end of the threaded rod to vary the distance between the surfaces. Device according to any one of claims 1 to 4, characterized in that the opposite surfaces are articulated along a long edge and each is provided with a threaded opening in the long free edge and the means for reducing the distance between them comprises a double-ended threaded rod which is provided with adjustment means such that the ends of the threaded rod can be received in the openings and the adjustment means can be rotated to vary the distance between the surfaces. Device according to any one of claims 1 to 4, characterized in that the opposite surfaces are parallel to each other. Device according to claim 7, characterized in that it comprises a cylindrical frame with a cavity running along its length, of rectangular cross section, cross section that increases linearly from one end to the other, and an insert rectangular cross section that similarly, and with triangular longitudinal section, it increases in a linear manner from one end to the other, the insert adapted to be received in the cavity whereby the opposite surfaces are constituted by a surface of the cavity and a parallel surface of the insert, and the means for varying the distance between the opposing surfaces comprises a collar with which the insert is mounted so that it can be inserted into the cavity and moved along the length of the cavity by the movement of the collar. Device according to claim 8, characterized in that the end of the frame from which the insert is inserted into the cavity is provided with a screw thread, the collar is provided with a reciprocating screw thread and the insert is mounted in the collar so that the insert can be moved along the length of the cavity by the engagement of the screw threads and the rotation of the collar relative to the frame. Device according to any one of the preceding claims, characterized in that the opposing surfaces are generally planar. 11. Equipment for enteral feeding, comprising a flexible tube and a device according to any of the preceding claims. 12. Equipment according to claim 11, characterized in that the flexible tube includes a portion made of an elastic material such as silicone or a silicone replacement synthetic material. 13. Equipment according to claim 11 or 12, characterized in that it is supplied ready assembled with the tube placed inside the device.