GB1590373A - Fluid flow control devices - Google Patents

Description

(54) IMPROVEMENTS RELATING TO FLUID FLOW CONTROL DEVICES (71) We, AUTO MEDICAL LIMITED, a British Company, of Old Station Road, Newent, Gloucestershire, do hereby declare the invent tion, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to apparatus for controlling a fluid flow through a flexible tube. The invention is particularly though not exclusively applicable to the control of fluids for medical purposes.

Broadly stated the invention consists in apparatus for controlling a fluid flow through a flexible tube, comprising a pair ofjaws, pivotally interconnected, for squeezing the tube, a remotely controlled solenoid actuator arranged to open the jaws, a lever linkage or transmission device connecting the actuator to one or both jaws and providing a mechanical advantage, and a spring and/or weight arranged to close the jaws, against the action of the actuator.

Preferably the apparatus includes means for adjusting the position of one of the jaws, which is relatively fixed and in a preferred construction a movable jaw is connected to a weight on an extended leverage arm. Conveniently one of the jaws provides a groove to receive the tube, and the other jaw is arranged to be moved into the groove to squeeze the tube.

The invention also consists in an apparatus for treating a fluid for medical purposes, incorporating flow control apparatus as defined arranged to squeeze a tube forming part of the apparatus.

The invention may be performed in various ways and one specific embodiment with some possible modifications will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 is a side elevation of the first embodiment in the form of a solenoid operated apparatus for squeezing a tube, Figure 2 is a plan view of the apparatus of Figure 1, Figures 3 and 4 are respectively side and end views of a modified form of device with an adjustable anvil, and Figure 5 is an end view of a complete fluid treatment machine for treating a patient for renal failure.

In these examples the device is intended primarily to be used in conjunction with a medical fluid treatment machine, for controlling the flow of the liquid effluent from a patient who is being treated for renal failure, or drug addiction, or for bladder irrigation, or in general for controlling the flow of fluid through any medical equipment.

The device illustrated in Figures 1 and 2 is designed for use in conjunction with a machine for use in treating renal failure, as illustrated for example in Figure 5. The treatment machine illustrated in Figure 5 includes a bank of liquid containers 50 acting as a reservoir for the liquid, and an electrically driven pump 51 supplying liquid from the containers to a pair of bags 52 carried by a stand 53. The flexible conduit 54 from the pump includes a teejunction 55 from which a branch 56 leads off through a heater 57 and an inflow valve 58 to an inflow line 59 leading to a patient. An outflow connection 60 acting as the return line from the patient leads through an outflow valve 61 to the metering dispenser unit 62 and then to a fluid connection 63 leading to sluice. The whole machine is mounted on a base 64 carried by small castor wheels and may include its own accumulator power supply or may have a flexible electrical connection to the mains.

The solenoid device illustrated in Figures 1 and 2 is designed for controlling the flow through a flexible plastic tube as indicated at 40 in Figure 3. The tube may be any one of the flexible tubes incorporated in the equipment of Figure 5, and in particular the valve may be used as valve 61 in the outflow tube 60. The tube is squeezed between a pair of jaws which in this example comprises a stationary anvil 41 and a movable jaw or plate 42.

The anvil is of channel shape providing a groove 43 in which the tube 40 is received, and there is a central cut-away portion or slot 44 across the anvil to allow for movement of the blade jaw 42. This jaw 42 is pivoted at 45 and forms part of a bell crank lever 46 whose other end is pivotally connected at the other end through a pin-and-slot joint to a push/pull rod or stem of an electromagnetic solenoid 48. The opposite end of this stem projects through the other end of the solenoid and is connected to a transverse plate 50 whose opposite ends are connected to a pair of springs 51 anchored at 52 to the stationary casing or support 53 which also carries the anvil 41, the solenoid 48 and the pivot point 45.

It will be seen that the action of the tension springs 51 is to pull the stem 47 to the right and hence to force the jaw blade 42 downwards to squeeze the liquid tube in its trough and hence close off the flow through the tube. When the solenoid 48 is actuated from a remote switch the stem 47 is moved against the action of the springs to raise the jaw blade and so open the valve. This provides an effective device for pinching a tube having appreciable rigidity and stiffness which could not be squeezed flat by a conventional solenoid of the same strength. It allows a solenoid valve to be fitted to the existing equipment without the need to replace the standard flexible tubing, or the need to insert soft silicone rubber inserts wherever a solenoid valve is to be fitted.

To ensure the blade closes onto the anvil in truly parallel attitude, so as to guarantee that the tube is fully closed, the anvil 41 may be mounted on an adjustable stem 65 as illustrated in Figures 3 and 4 and fixed in any position of adjustment by means of a locking screw 66.

In a possible modification of the solenoid mechanism illustrated in Figures 1 and 2 the springs 51 may be replaced or augmented by a gravity system in which the jaw 42 is pivoted as in the previous example and the bell crank lever 46 is rigidly connected also to an inclined extended leverage arm having a heavy weight at its remote end. This exerts a considerable leverage on the jaw 42 sufficient to close the tube 40, and may be used either to replace the action of the springs 51 or to augment the force of the springs if preferred.

WHAT WE CLAIM IS: 1. Apparatus for controlling a fluid flow through a flexible tube, comprising a pair of jaws, pivotally interconnected, for squeezing the tube, a remotely controlled solenoid actuator arranged to open the jaws, a lever, linkage or transmission device connecting the actuator to one or both jaws and providing a mechanical advantage, and a spring and/or weight arranged to close the jaws, against the action of the actuator.

2. Apparatus according to Claim 1, including means for adjusting the position of one of the jaws, which is relatively fixed.

3. Apparatus according to Claim 1 or Claim 2, in which a movable jaw is connected to a weight on an extended leverage arm.

4. Apparatus according to any of the preceding claims, in which one of the jaws provides a groove to receive the tube, and the other jaw is arranged to be moved into the groove to squeeze the tube.

5. A fluid control apparatus substantially as described with reference to Figures 1 and 2, or Figures 3 and 4 of the accompanying drawings.

6. Medical fluid supply and control apparatus incorporating a fluid control apparatus in accordance with any of the preceding claims.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. or stem of an electromagnetic solenoid 48. The opposite end of this stem projects through the other end of the solenoid and is connected to a transverse plate 50 whose opposite ends are connected to a pair of springs 51 anchored at 52 to the stationary casing or support 53 which also carries the anvil 41, the solenoid 48 and the pivot point 45. It will be seen that the action of the tension springs 51 is to pull the stem 47 to the right and hence to force the jaw blade 42 downwards to squeeze the liquid tube in its trough and hence close off the flow through the tube. When the solenoid 48 is actuated from a remote switch the stem 47 is moved against the action of the springs to raise the jaw blade and so open the valve. This provides an effective device for pinching a tube having appreciable rigidity and stiffness which could not be squeezed flat by a conventional solenoid of the same strength. It allows a solenoid valve to be fitted to the existing equipment without the need to replace the standard flexible tubing, or the need to insert soft silicone rubber inserts wherever a solenoid valve is to be fitted. To ensure the blade closes onto the anvil in truly parallel attitude, so as to guarantee that the tube is fully closed, the anvil 41 may be mounted on an adjustable stem 65 as illustrated in Figures 3 and 4 and fixed in any position of adjustment by means of a locking screw 66. In a possible modification of the solenoid mechanism illustrated in Figures 1 and 2 the springs 51 may be replaced or augmented by a gravity system in which the jaw 42 is pivoted as in the previous example and the bell crank lever 46 is rigidly connected also to an inclined extended leverage arm having a heavy weight at its remote end. This exerts a considerable leverage on the jaw 42 sufficient to close the tube 40, and may be used either to replace the action of the springs 51 or to augment the force of the springs if preferred. WHAT WE CLAIM IS:

1. Apparatus for controlling a fluid flow through a flexible tube, comprising a pair of jaws, pivotally interconnected, for squeezing the tube, a remotely controlled solenoid actuator arranged to open the jaws, a lever, linkage or transmission device connecting the actuator to one or both jaws and providing a mechanical advantage, and a spring and/or weight arranged to close the jaws, against the action of the actuator.

2. Apparatus according to Claim 1, including means for adjusting the position of one of the jaws, which is relatively fixed.

3. Apparatus according to Claim 1 or Claim 2, in which a movable jaw is connected to a weight on an extended leverage arm.

4. Apparatus according to any of the preceding claims, in which one of the jaws provides a groove to receive the tube, and the other jaw is arranged to be moved into the groove to squeeze the tube.

5. A fluid control apparatus substantially as described with reference to Figures 1 and 2, or Figures 3 and 4 of the accompanying drawings.

6. Medical fluid supply and control apparatus incorporating a fluid control apparatus in accordance with any of the preceding claims.