Multi stage type flow rate switching device

Abstract: A multi stage type flow rate switching device is provided which simplifies switching of flow paths and which rarely causes erroneous operation. The multi-stage type flow rate switching device includes a liquid medicine flow inlet port 1 having branch paths 11, 12 and 13 on a downstream side, a liquid medicine flow outlet port 2 having branch paths 21, 22 and 23 on an upstream side and constant flow rate paths 31, 32 and 33 for connecting respectively of the branch paths, and they are arranged in a housing 4 comprising a lid 41 and a housing main body 42. In the housing 4, there is provided clamping means 5 capable of selectively blocking the constant flow rate paths 31, 32 and 33.

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention: The present invention relates to a multi stage type flow rate switching device. More particularly, the present invention relates to a multi stage type flow rate switching device suitable for controlling variably a small flow rate by being connected to a ballooned liquid medicine continuous injector (an injector where liquid medicine is filled in a balloon made of an elastic rubber material and liquid medicine is continuously injected over a period of many hours into a human body by utilizing the force produced by contraction of the balloon) that is used as a means for continuously administering a liquid analgetic, anesthetic, antibiotic, or carcinostatic agent into blood vessels, hypodermic portions, epidural portions or the like in a small amount. 2. Description of Related Art: With respect to a variable small flow rate control device used in a ballooned liquid medicine continuous injector, a device comprising flow rate control tubes connected to a multi-way stopcock has already been proposed (Japanese Unexamined Patent Publication No. JP-A-5-84310). The device is constituted by a main body having a cylindrical valve chamber where one flow inlet port and at least three flow outlet ports are formed. A plug having a cylindrical valve portion is rotatably inserted into the valve chamber of the main body. A slit opened in a fan-like shape and slender holes in a straight tube shape extending opposedly in a radial direction from the base of the slit, are formed at the valve portion and, even if the slender holes of the valve portion are connected to any of the flow outlet ports, the slit is connected to the flow inlet port. However, according to the above-described flow rate control device, one flow rate control tube is necessary for each flow outlet port and various sizes of the flow rate control tubes are necessary. It is troublesome in view of production control and assembly operation to fabricate various sizes of flow rate control tubes and integrate them simultaneously. Also, the use thereof involves a drawback where the switch angle of the lever is decreased for a large number of switchings and the display is complicated whereby erroneous operation is liable to occur. Furthermore, US 5,318,515 discloses a device for regulating fluid flow in an intravenous line comprising a housing and a flow part system in the housing for determining a plurality of separate flow paths having respective predetermining characteristic flow rates. The separate flow paths are clampable by plural flow path pressing means which are constituted by toggle switches operable from outside of the housing of the flow rate switching device. The flow rate switching to device according US 5,318,515 has especially the disadvantage that the flow rate can be changed from outside of the device and therefore there is the risk that the flow rate is changed by the patient accidentally. Furthermore, the toggle switches have to be mounted pivotably and therefore cause high manufacturing costs. The present invention has been achieved as a result of an intensive study in view of the above-described situation and it is an object of the present invention to provide a multi stage type flow rate switching device which simplifies production steps, which can be fabricated at a low cost and which simplifies switching of flow path and rarely causes erroneous operation and prevents accidentals changes of the flow rate. SUMMARY OF THE INVENTION According to the present invention, there is provided a multi stage type flow rate switching device including a liquid medicine flow inlet port having plural of branch paths on a downstream side, a liquid medicine flow outlet port having plural branch paths on an upstream side, constant flow rate paths for connecting the plural branch paths of the liquid medicine flow inlet port and the plural branch paths of the liquid medicine flow outlet port, and a housing comprising a lid and a main body and capable of accommodating and arranging the plural constant flow rate paths. In the housing, there is provided clamping means which is capable of selectively blocking the plural constant flow rate paths. The clamping means of the present invention comprises flow path pressing means whose number is equal to a number of the constant flow rate paths and the flow path pressing means are provided on the opposite side of the constant flow rate paths. The flow path pressing means are constituted by plural plate members provided foldably by hinges at the rear side of the lid of the housing, and each of the plate members is provided with a pressing portion for blocking each of the constant flow rate paths on one side thereof. When the plate member is folded, the pressing portion is brought into a state of blocking the constant flow rate path and when the plate member is unfolded, the pressing portion is brought into a state of not blocking the constant flow rate path. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an explanatory view showing an embodiment of a multi stage type flow rate switching device according to the present invention (showing a state where a lid of a housing is closed); Fig. 2 is a plane view of essential portions of the multi stage type flow rate switching device shown by Fig. 1 (showing a state where the lid of the housing is opened); Fig. 3 is a sectional view taken along a line III-III of the multi stage type flow rate switching device shown by Fig. 1; Fig. 4 is an explanatory view illustrating flow rate switching operation of the multi stage type flow rate switching device shown by Fig. 1; Figs. 5(a), 5(b), 5(c), 5(d), 5(e), 5(f), 5(g) and 5(h) are plane views showing combinations of clamps according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention is explained below with reference to the drawings. As shown by Fig. 2, a multi stage type flow rate switching device of the present invention includes a liquid medicine flow inlet port 1 having three branch paths 11, 12 and 13 on a downstream side, a liquid medicine flow outlet port 2 having three branch paths 21, 22 and 23 on an upstream side, and a flow rate control unit where constant flow rate paths 31, 32 and 33 for connecting respectively of the branch paths 11, 12 and 13 and the branch paths 21, 22 and 23, and they are accommodated and arranged in a housing 4 having an openable and closable lid 41. As shown by Fig. 1, tubes 81 and 82 are respectively attached to the liquid medicine flow inlet port 1 and the liquid medicine flow outlet port 2, and connectors 91 and 92 are respectively provided at another ends of the tubes 81 and 82. Here, the constant flow rate paths 31, 32 and 33 may be connected to the branch paths 11, 12 and 13 or the branch paths 21, 22 and 23 respectively through connection tubes 61, 62 and 63 which can be pressed and blocked by being pressed by a clamping means 5. Although according to the embodiment the constant flow rate paths 31, 32 and 33 are connected to the branch paths 21, 22 and 23 of the liquid medicine flow outlet port 2 through the connection tubes 61, 62 and 63, the connection tubes 61, 62 and 63 may integrally be formed with the branch paths 11, 12 and 13 of the liquid medicine flow inlet port 1 or the branch paths 21, 22 and 23 of the liquid medicine flow outlet port 2. Although the constant flow rate paths 31, 32 and 33 may be set to the same flow rate, it is preferable to set them to the different flow rates if combinations of switchings of flow rates are intended to increase in number. According to the embodiment, the flow rates are made to differ from each other by changing lengths of the constant flow rate paths 31, 32 and 33. A number of the constant flow rate paths in the present invention is not limited to three but the number may be increased or decreased as necessary. The housing 4 comprises the lid 41 and a housing main body 42, and the lid 41 and the housing main body 42 are openable and closable by mutual engaging means. Incidentally, a locking means may be provided to the housing 4 so that a patient cannot open or close it easily. It is preferable that grooves 431 and 432 or the like are provided to the housing 4 so that the liquid medicine flow inlet port 1, the liquid medicine flow outlet port 2 and the constant flow rate paths 31, 32 and 33 are fixed in the housing 4. Further, the clamping means 5 comprising plate members 51, 52 and 53 foldable by hinges 512, 522 and 532 are provided at the inside rear face of the lid 41. The projections 511, 521 and 531 are respectively provided at one side of the plate members 51, 52 and 53 as pressing portions capable of blocking the constant flow rate paths 31, 32 and 33. The plate members 51, 52 and 53 become foldable when the housing 4 is opened. The plate members 51, 52 and 53 are arranged such that when they are folded, the projections 511, 521 and 531 block the constant flow rate paths 31, 32 and 33. Here, the inside of the projections 511, 521 and 531 of the plate member 51, 52 and 53 may be engaged with the inside of the lid 41, when the plate members 51, 52 and 53 are folded. For example, It may be adopted a method that recesses (or projections) are provided at the lid 41 and the plate members 51, 52 and 53 and these are engaged with each other. Although the position of the clamping means 5 is not particularly limited so far as the constant flow rate paths 31, 32 and 33 (or connection tubes 61, 62 and 63) can be blocked at the position, in the case where the liquid medicine flow inlet port 1 arid the liquid medicine flow outlet port 2 are fixed to the housing 4 as in this embodiment, the clamping means 5 is preferably provided at a proximity of the liquid medicine flow inlet port 1 or the liquid medicine flow outlet port 2. In this case, the constant flow rate paths 31, 32 and 33 are preferably connected to the liquid medicine flow inlet port 1 or the liquid medicine flow outlet port 2 through the connection tubes 61, 62 and 63 where the clamping means 5 blocks the constant flow rate paths 31, 32 and 33 by pressing to close the connection tubes 61, 62 and 63. The constant flow rate paths 31, 32 and 33 or the connection tubes 61, 62 and 63 which are pressed to cblock by the clamping means 5, are preferably formed by elastic tubes so that portions which have been blocked are restored to original shapes when the flow rate is switched. It is preferably made of soft polyvinyl chloride, silicone rubber, thermoplastic elastomer or the like. Further, although a window 411 is provided at the lid 41 according to the embodiment, the window is not particularly necessary so far as the constant flow rate paths 31, 32 and 33 are not on danger of being pressed to block by the plate members 51, 52 and 53 when the constant flow rate paths 31, 32 and 33 are not in position to be pressed to block by the plate members 51, 52 and 53. Further, although the plate members 51, 52 and 53 of the embodiment are integrally formed with the housing 4 and are foldable by forming the hinges 512, 522 and 532 having a thin wall thickness, in this case, the material of forming the housing 4 is preferably made of a material capable of forming hinges 512, 522 and 532 such as polyethylene, polypropylene, polystyrene, hard polyvinyl chloride or the like is adopted. According to the present invention, the plate members 51, 52 and 53 may be separately formed and may be attached to the inside of the lid 41. Further, the clamping means 5 is not necessarily provided the projections so far as the constant flow rate paths 31, 32 and 33 can be blocked. For example, the thicknesses of the plate members 51, 52 and 53 may be increased to a degree capable of blocking the constant flow rate paths 31, 32 and 33. Further, a rise portion 422 or the like may be provided to the housing main body 42 to help blocking the constant flow rate paths 31, 32 and 33 by the projections 511, 521 and 531. Explaining in details with respect to the blocking mechanism of the present invention, as shown by Fig. 4, when the housing 4 is closed, the plate member 52 is brought into a state of not blocking the constant flow rate path 32. When the housing 4 is opened, the plate member 52 is brought into a state capable of being folded. When the plate member is folded by opening the housing 4 and then the housing 4 is closed, the constant flow rate path 32 is pressed and blocked. In order to set the flow rate of the flow rate switching device, there are eight ways shown by Figs. 5(a), 5(b), 5(c), 5(d), 5(e), 5(f), 5(g) and 5(h). For example, in these drawings, Fig. 5(a) shows a state of the blocking means 5 clamping the constant flow rate paths 31 and 32. Fig. 5(b) shows a state of the clamping means 5 blocking the constant flow rate paths 31 and 33. Fig. 5(c) shows a state of the clamping means 5 blocking the constant flow rate paths 32 and 33. Fig. 5(d) shows the state of the clamping means 5 blocking the constant flow path 31. Fig. 5(e) shows a state of the clamping means 5 blocking the constant flow rate path 32. Fig. 5(f) shows the state of the clamping means 5 blocking the constant flow rate path 33. Fig. 5(g) shows a state of the clamping means 5 blocking all of the constant flow rate paths 31, 32 and 33. Further, Fig. 5(h) shows a state of the clamping means 5 where all of the constant flow rate paths 31, 32 and 33 are not blocked. Incidentally, the housing 4 according to the present invention can be used at any numbers of times so far as the constant flow rate path blocking mechanism operates normally (so far as the hinges are not weakened to break). According to the multi stage type flow rate switching device of the present invention, the relationship between combinations of flow paths and the flow rate is as illustrated by Table 1 when the flow rates of the constant flow rate paths are set as follows. As is apparent from the above-described explanation, the multi stage type flow rate switching device of the present invention is provided with a simple structure where the constant flow rate paths are pressed to block by the clamping means. Therefore, the present invention has advantages where the fabrication is facilitated and the device can be fabricated at a low cost. Further, flow path switching operation is simple and accordingly, erroneous operation is rarely caused.

Claims: A multi stage type flow rate switching device comprising: a liquid medicine flow inlet port (1) having plural branch paths (11, 12, 13) on a downstream side; a liquid medicine flow outlet port (2) having plural branch paths (21, 22, 23) on an upstream side; constant flow rate paths (31, 32, 33) for connecting the plural branch paths (11, 12, 13) of the liquid medicine flow inlet port (1) and the plural branch paths (21, 22, 23) of the liquid medicine flow outlet port (2); a housing (4); and clamping means (5) provided in the housing (4), said clamping means (5) being capable of selectively blocking the plural constant flow rate paths (31, 32, 33); wherein the clamping means (5) is constituted by plural flow path pressing means having a number equal to a number of the plural constant flow rate paths (31, 32, 33) and the plural flow path pressing means are provided on the opposite side of the constant flow rate paths (31, 32, 33); characterized in that the housing (4) comprises, a lid (41) and a housing main body (42), said housing (4) being capable of accommodating and arranging the plurality of constant flow rate paths (31, 32, 33) said plural flow path pressing means comprising plural plate members (51, 52, 53) provided foldably by hinges (512, 522, 532) at an inside side of the lid (41) of the housing (4), and each of the plate members (51, 52, 53) is provided with a pressing portion (511, 521, 531) for blocking each of the constant flow rate paths (31, 32, 33), wherein when said plate member (51, 52, 53) is folded, said pressing portion (511, 521, 531) is brought into a state of blocking each of said constant flow rate paths (31, 32, 33), and when said plate member (51, 52, 53) is unfolded, said pressing portion (511, 521, 531) is brought into a state of not blocking each of said constant flow rate paths (31, 32, 33).

Inventors: HIEJIMA KATSUHIRO, HIEJIMA, KATSUHIRO, HIEJIMA, KATSUHIRO C/O NIPRO CORPORATION
Applicants: NIPRO CORP, NIPRO CORPORATION
Application year: 1997
Main classification: A61M5
IPC codes: A61M5