Surgery – Respiratory method or device – Means for mixing treating agent with respiratory gas
Reexamination Certificate
1998-08-19
2001-10-16
Weiss, John G. (Department: 3761)
Surgery
Respiratory method or device
Means for mixing treating agent with respiratory gas
C128S200190, C128S204140, C128S205240
Reexamination Certificate
active
06302104
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to an interlock arrangement for evaporators in an anesthesia apparatus, the anesthesia apparatus being of the type having at least two evaporators connectable to a gas distributor for setting a desired gas concentration as well as means for preventing more than one evaporator from being activated at a time.
2. Description of the Prior Art and Related Application
An anesthesia apparatus is disclosed in the Swedish Patent No. 507 899 having at least two evaporators for setting a desired gas concentration and a valve belonging to each evaporator, the valve controlling the gas flow through the respective evaporator, as well as means for enabling an opening and a closing of the valves that simultaneously prevent more than one evaporator from being activated. The evaporators and the valves are connectable to a gas distributor.
This anesthesia apparatus is provided with an evaporator carousel forming the gas distributor or the holder for the evaporators and valves and a gas supply unit, the gas distributor being rotatable relative to the gas supply unit. As a result, it is simple for a physician to change position relative to the patient and nonetheless have control over which evaporator is activated and what anesthesia concentration has been set at the active evaporator. As needed, the anesthesiologist can change the concentration of the anesthetic despite changing work positions, by rotating the gas distributor or holder, so that the activated evaporator is in a good position for the change in the concentration that has been set. In order to avoid having more than one evaporator activated at the same time, these applications state that an interlock arrangement is present, but details of such an interlock arrangement are not disclosed in detail in these applications.
U.S. Pat. No. 4,307,718 discloses an interlock arrangement for two evaporators arranged side-by-side in an anesthesia apparatus. Each evaporator has a cylindrical container with a rotary dial thereon as a cover, which is also used for setting the vapor concentration. Each adjustment dial has a recess at the cylindrical peripheral surface thereof. The interlock arrangement is formed by an arm which is pivotable around a shaft, the arm being provided with an outwardly directed pin arranged at each end, and the pins can be brought into engagement with the recesses. When the arm is pivoted into a position in which one pin is in engagement with the recess of one adjustment dial and closes this evaporator, the other evaporator can be set into a desired position, and vice versa. Such an interlock arrangement is exclusively limited to two evaporators.
SUMMARY OF THE INVENTION
An object of the present invention is to interlock arrangement of the type initially described, particularly for use in conjunction with an evaporator carousel with a plurality of evaporators, which assures that only one evaporator can be set at a time, in a way that is simple and dependable for the user.
The above object is achieved in accordance with the principles of the present invention in an anesthesia apparatus having at least two evaporators, with each evaporator being provided with a mechanical element which is actuated when that evaporator is activated, the respective mechanical elements of the evaporators crossing each other in a crossing region and interacting with each other in the crossing region so that when one of the mechanical elements is actuated upon activation of its associated evaporator, that mechanical element is placed in a position which locks the other mechanical elements and thereby prevents activation of any other evaporator.
The above object is also achieved in an anesthesia apparatus having a plurality of evaporators, with each evaporator having a valve associated therewith which is opened and closed to activate that evaporator, and wherein each evaporator has a mechanical element associated therewith which is actuated when the evaporator is activated by opening its valve. The respective mechanical elements of the evaporators cross each other in a crossing region and interact with each other in the crossing region so that when one mechanical element is actuated by opening the valve of the evaporator associated therewith, the actuated mechanical element forces the other mechanical elements into respective positions so that the respective valves of the other evaporators associated therewith are closed, and activation of any of the other evaporators is thereby prevented.
In an embodiment of the invention the evaporators with the appertaining valves are arranged exactly opposite one another. As a result, the shape of the mechanical elements can be comparatively simple and inexpensive to manufacture.
Preferably, each mechanical element is composed of at least one slide. To allow the interlock arrangement to be more easily assembled during production, it can be advantageous for each mechanical element to be composed of two slides that lie in axial alignment with one another. As used herein, therefore, the term “mechanical element” means a single part, or two parts acting together as a single part.
The slides can be shaped such that they can intermesh with one another in the crossing region. This allows the ends of the various slides to lie in approximately the same plane, which means that all evaporators and valves can be attached to the gas distributor at the same height.
In another embodiment of the invention at least three evaporators are arranged at the gas distributor and each of the slides has a trapezoidal shoulder that is disposed in a plane in the crossing region and which has an obtuse end directed toward an imaginary central point in the crossing region. When an evaporator is activated, the slide for this evaporator is displaced along its longitudinal direction, and thus the shoulder is displaced toward the central point into a position in which this shoulder locks or blocks the other shoulders and thus prevents the remaining slides from being capable of being displaced into an active evaporator position. As a result, an interlock arrangement is established that, in a way that is dependable for the user, assures that only one evaporator can be regulated at a time, even in conjunction with three or more evaporators.
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patent: 507 899 (1998-07-01), None
Schiff & Hardin & Waite
Siemens Elema AB
Srivastava V.
Weiss John G.
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