US 3708963 A
A tent like assembly, preferably in the form of a tubular duct of transparent, flexible plastic material, is suspended from a framework to define a dust-free patient isolation chamber which is large enough to accommodate attending personnel. Air, introduced into one end of the chamber via a dust filtering means, flows horizontally through the chamber and exits therefrom through the discharge opening in the other end of the chamber. This air flow, which is substantially non-turbulent and is directed generally throughout the entire height and width of the chamber, maintains the chamber substantially dust free. Attending personnel enter the chambers through a door, which normally closes a major portion of the discharge chamber and defines the discharge opening. The air flow is controlled to prevent dust in the surrounding atmosphere from entering the chamber while the door is open and tends to purge away any dust which might otherwise be introduced by entering personnel. Treatment apparatus and the like can be introduced into the chamber through closeable transfer openings in the side of the tent.
Claims available in
Description (OCR text may contain errors)
United States Patent Boonstra et al.
Jan. 9, 1973  ASSEMBLY FOR SEPARATING A ment" by S. M. Levenson et al. American Journal of SUBSTANTIALLY DUST-FREE PART FROM A SPACE Surgery, Vol. 104, December 1962 pages 891 to 899.
Primary Examiner--Arthur D. Kellogg Attorney-Bayard H. Michael  ABSTRACT A tent like assembly, preferably in the form of a tubu-  inventors: Willem Frederik Boonstra, Mozartlaan 6, Castricum; Tabe Ernst Meindersma, Merelhoven llO, Capelle aan de (ssel; Piet Van Galen, Vlietlaan 81, Assendelft, all of Netherlands lar duet of transparent, flexible plastic material, is
 Filed: Sept 8 1970 suspended from a framework to define a dust-free patient isolation chamber which is large enough to acl pp ,454 commodate attending personnel. Air, introduced into one end of the chamber via a dust filtering means,
flows horizontally through the chamber and exits  Foreign Application Priority Data Sept. I0, 1969 Netherlands........,..............
therefrom through the discharge opening in the other which is substanand is directed generally throughout the entire height and width of the 69l38l0 end of the chamber. This air flow 30 9 7m 7 we 3 am. 6M4 3B 4 1 o n n 3 m m y m .0 5 "M C S 5 W n n e n r. Hm w nmh E mm R 2 H "S L C rm Smk UIlF ll] l 2 00 6 555 5 The air flow is controlled to prevent dust in the surrounding atmosphere from entering the chamber while the door is open and tends to purge away any dust U NITED STATES PATENTS which might otherwise be introduced by entering personnel. Treatment apparatus and the like can be introduced into the chamber through closeable transfer openings in the side of the tent.
m o .H v u n .m E m 1 Wm Wa mrln WMM mm m; wo TR... r Hr Tm Oh o b .m t s m P 3,l48,956 9/1964 Hetherwick et al. 2,359,057 9/1944 Skinner 3,433,949 3/1969 ll Claims, 6 Drawing Figures PATENTEDJAH 9 ms n Y AA WW m BMW, E W, 6M WW W 5 Mm M f v ASSEMBLY FOR SEPARATING A SUBSTANTIALLY DUST-FREE PART FROM A SPACE BACKGROUND OF THE INVENTION So called dust-free cabinets are used when work is to be performed in an environment from which dust-laden air is to be excluded. These cabinets surround a work surface and are provided with an access opening. Means are provided for drawing air into the cabinet and the air, temperature and the humidity of which can be regulated if necessary, is passed through very fine air filters and then directed through the cabinet toward the access opening. These filters are constructed to provide a laminar air flow at relatively low velocity, thereby producing a continuous expulsion of air from the cabinet without substantial turbulence. Thus, dust is kept outside the cabinet space or is expelled therefrom. It is important to avoid turbulences, which can cause the dust to be circulated towards the interior of the cabinet and thereby disturb the expulsion effect.
It is also known to keep an entire work area dust free in a comparable manner. Air is introduced into the work space through a filter generally arranged in the upper wall thereof and is discharged through means generally located in or near the floor. Thus, a substantially vertical air flow is maintained through the work spaced area.
As mentioned above, the air flow in dust-free cabinets or work space areas should have the least amount of turbulence possible, since any turbulence may drag dust inwardly toward the area desired to be maintained dust free. The downward flow of air through work space areas urges dust introduced by personnel present in the work area towards the floor. However, movement of these personnel in the work space area unavoidably causes considerable turbulences which can cause the dust to be carried toward the work surface.
For some special cases in hospitals, e.g. after a transplantation, during some cancer treatment, severe burn cases and the like, it is necessary to nurse the patients in a germ-free environment. Since dust carries microorganisms and the like, the environment should be dust free. Special isolation spaces, into which clean air is continuously introduced in a manner similar to that described above for work space areas, have been used for this purpose.
Such isolation spaces have several disadvantages. All personnel and apparatus in the germ-free environment should be as dust free as possible. Consequently, in order to prevent the introduction of dust into the space, all entering personnel should put on dust free outer clothing, even if they are only to have superficial con tact with the patient. This causes inconvenient loss of time, especially for doctors or attendants who do not work exclusively in the isolation department. Moreover, it is generally impossible, or at least very troublesome, for visitors to be admitted into the germfree environment. This is detrimental for maintaining a proper mental condition for enhancing recovery of the patient.
Expensive apparatus to be used in the isolation department, such as X-ray apparatus, artificial organs and the like, must be kept separate or subjected to a timeconsuming dust removal operation. This can involve considerable additional expense and can cause unacceptable delays in emergency cases.
When vertical air flows are used, as mentioned above for work space areas, a dust-free condition is not sufficiently maintained. Attending personnel moving about within the work space area can cause the dust to whirl upwardly with the resultant danger of the air flow through the space carrying dust from these personnel directly to a patient being attended.
SUMMARY OF THE INVENTION This invention provides an assembly for separating and maintaining a portion of the space dust free so it is not necessary for the space itself or personnel and apparatus and other portions of the space to meet the very severe requirements of being dust free. The assembly is arranged so that a patient in the separated portion can be attended without disturbing its dust-free condition and, at most, only those personnel having direct bodily contact with a patient need satisfy stricter dust-free conditions. The assembly can be used for other applications where similar environmental conditions are required.
The dust-free assembly according to this invention comprises a chamber defined in part, by an upper wall and side wall supported by a framework, a dust filtering means defining one end of the chamber and an air supply means, which introduces air flow into the chamber via the dust filtering means and directs horizontal air flow of minimal turbulence over substantially the full width and height of the chamber towards the opposite end of the chamber. This opposite end of the chamber includes an opening which serves both as an air discharge opening and an access opening. At least the side walls of the chamber are formed from stretched or suspended sheet or plate material, preferably from a transparent plastic.
A bed and other absolutely necessary devices can be placed inside the chamber. Personnel directly contacting the patient can enter the chamber through the access opening against the horizontal air flow, without the risk of causing whirling of dust. Since all other devices and treatment apparatus not requiring a direct contact of the patient may be located outside the chamber, they do not have to submitted to special cleaning treatment. Persons who do not need to contact the patient directly, such as attending personnel, visitors, and for a considerable part also doctors, may be admitted without special precautions outside the dust-free chamber. They may have unimpeded contact with the patient since the plastic material transmits sound and light. The smooth plastic sheet or plate material may be easily disinfected, or may be discarded in view of its relatively low cost.
Another advantage is that the usual sluices for dustfree rooms may be omitted since the room in which the reduction in the air flow and the filters do not become soiled as rapidly. Moreover, the reduced air flow results in a lower level of ventilation fan noise which enhances patient comfort. Switch means can be provided for adjusting the air supply means so its output corresponds to the degree the closing means is closed. Preferably, the air flow in the chambers is maintained as non-turbulent as possible when the closing means is closed. In order to avoid local pressure rising inside the chamber, with resultant undesirable turbulence, it may be advisable to provide the closing means with leakage passages. Preferably the closing means is a movable front wall in the form of a closable door, which is pivotable about a horizontal axis located at the upper side of the frame. This door can be covered with a plastic sheet material forming part of the upper chamber wall.
Preferably, the top, bottom and side walls of the chamber are formed by a tubular plastic duct which is preferably suspended in a yieldable manner on the framework with one end of the duct being connected to the air supply means in an air tight manner. At least one of the side member chamber sides is preferably provided with elastically deformable portions to a allow the introduction of treatment apparatus and the like into the chamber without introducing dust. These deformable portions can be in the form of inwardly extending pockets in the side wall. Also, one or more closable transfer openings can be provided at least one of the side walls. A transfer box can be provided on the framework with a corresponding opening being provided on the chamber side wall which is clamped onto the box in an air tight manner.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of a dust-free chamber assembly according to this invention;
FIG. 2 is a longitudinal section of the assembly;
FIG. 3 is a longitudinal section of a modified form of the access door for the assembly;
FIG. 4 is a transverse section of the assembly shown in FIG. 1;
FIG. 5 is an enlarged fragmentary view of an upper corner of the assembly; and
FIG. 6 is an enlarged fragmentary view showing the connection between the chamber housing and the air supply means.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The assembly illustrated in the drawings comprises a transportable housing 1 which can be supported on the floor 2 of a room or other space and includes means (e.g., ventilation fans) for drawing air into the housing and means for regulating its temperature and humidity if necessary. Air filter elements 3 are provided at the vertical front side of housing 1. Filter elements 3, which are covered by apertured screen 4, can be removed and replaced when soiled.
Housing I is connected to a framework 5 comprising a number of horizontal and vertical frame members and is of sufficient size to accommodate a bed 6 and several nursing personnel. A tent, made of a thin, flexible and transparent plastic material 7, is suspended from framework 5. The tent in the embodiment shown comprises a tubular plastic duct extending longitudinally between screen 4 and the opposite wall of framework 5 and also covers floor 2. Framework 5 is dismountable or foldable, so that the whole assembly can be easily stored when not in use. Plastic material 7 can be easily cleaned and disinfected or can be discarded or destroyed after use.
Uniformly and substantially non-turbulent air flows 8 are discharged from screen 4 and are directed towards discharge opening 9 of the tent. Personnel entering the tent via opening 9 walk against the air flow so that any dust which may be whirled up by them is blown away behind them. Of course, such personnel should preferably wear non-fluffing clothes and can be subjected to a dust removing treatment if necessary.
Persons who need not touch the patient, such as visitors and doctors or assistants who do not directly participate in the examination, can observe the patient and speak to him from outside the tent.
Furthermore, devices such as X-ray apparatus, transfusion or infusion bottles, artificial organs and measuring and observation instruments, can be completely or partly disposed outside the tent with the side walls of the tent being provided with inlet openings for this purpose. When the wall of the tent is sufiiciently resilient and is resiliently suspended from framework 5, it is possible to push an X-ray apparatus or the like together, with the wall, inwardly up to the vicinity of the patient. It is also possible for the side walls to include deformable or extendable portions of pockets for allowing certain operations without entering the tent.
As shown in FIG. I, a transfer box or lock 10 is incorporated in the framework 5 to permit auxiliary personnel outside the tent to pass the required objects into the tent through transfer lock 10, thereby reducing the number of personnel required inside the tent. lf necessary, lock 10 can be provided with disinfection means, such as ultraviolet lamps. The tent is provided with a preformed opening to be aligned with lock 10, or is cut open next to the lock after mounting, and can be clamped in a flange of lock 10. Also the extendable portion or pockets mentioned above can be arranged in a similar lock which supports the wall around these parts.
The transfer inlets in the tent can be closed by means of a length of flexible tubular plastic ducting, both ends of which are kept open by means of a substantially rigid hoop with the intermediate part of this duct being pinched closed by relative rotation of the hoops.
When opening 9 is completely opened, the flow rate of the air required to maintain a dust-free condition is relatively high and will cause a rapid soiling of filter elements 3. A high air flow rate is, in fact, only required when personnel is entering the tent. Also, the ventilator fans and the high air flow itself cause a noise which may be annoying to the patient. Therefore, the major portion of opening 9 is preferably closed by a door 11 during the time that nobody is to enter the tent, a gap being left between the lower edge of the door and the floor of the tent. The output of the ventilator flange can be reduced (while maintaining a sufficient air flow) so that soiling of the filter elements 3 will be reduced accordingly and the comfort of the patient enhanced.
Door 11 comprises a frame 12 which is pivotable about a horizontal axis 13 mounted on the upper side of framework 5. Door 11 is pivotable between a substantially horizontal position in which the opening 9 is fully open and in the inclined position as illustrated. Frame 12 is covered with a stretched end portion of the upper side of plastic material 7, frame 12 being provided with suitable clamping means for this purpose. The end portion of plastic material 7 can be cut at the upper edge from the side wall and the latter then fixed to framework 5. [t is also possible to leave the upper portion integral with the side walls, in which case provision should be made for forming gussets in the side walls, e.g., by means of elastic tensioning strips or the like.
Door 11 is preferably provided with locking means 14 for retaining it in its closed position and a counter weight 15 or a spring that serves a similar purpose. 15
Moreover, flexible air guide plates 16 and 17 are arranged at the upper and lower edges respectively of door 11 in order to obtain an air flow which is non-turbulent as possible in the vicinity of door 11. A switch 25 can be connected to the frame 12 for regulating the output of the ventilator fans corresponding to the degree door 11 is opened. Preferably, movement of the door is controlled by a damper in order to prevent movement which is too rapid to permit corresponding adjustments of the ventilator fans.
Frame 12 of door 11 can be provided with a permanent cover formed by means other than plastic material 7. In order to. further reduce turbulence when door 11 is closed, it can be provided with leakage apertures 18 as shown in FIG. 3. These leakage apertures serve to prevent excessive build-up of pressure behind the door.
The tent can be provided with longitudinal pockets 19 (FIG. 5) near the upper horizontal members of framework 5 and, if necessary, also near the floor 2. A tensioning bar 20, a tension spring or ribbon may be inserted in each of these pockets to tension the tent. The tensioning bar or the like can be suspended from framework 5 by means of tension springs 21 with pocket 19 being provided with corresponding openings. Alternately, suspension straps can be fitted to the plastic material 7.
The end portion 22 of the tent adjacent housing 1 is provided with elongated pockets into which a tension string 23 or the like can be inserted. String 23 serves to clamp the end portion of thetent to a corresponding rim 24 on housing I in an air-tight manner. Such a connection may also be provided around the transfer lock. Clamping rims or other suitable connecting means can be used to make either of these connections.
it will be clear that the invention is not restricted to the embodiment described. For instance, a bottomless tent can be used, provided that the connection to the floor is sufficiently dust proof. Since such a connection is often difficult to provide, it is generally preferred that the tent be in the form of a tubular duct.
The upper surface of the chamber can be formed by a closed upper surface of the framework which is detachable from the remainder of the framework. In this case, the side walls can be formed from a material which can be wound up or a plate material. instead of using a pivotable door for the access opening, a flap secured by slide fasteners, a roller blind, or the pinch valve arrangement mentioned above can be used. However, the pivotable door has the advantage of providing a general transition for the air flows and also can be quickly and easily opened. The air supply means in housing 1 may be simplified to utilize the central air conditioning system if the system has a sufficient pressure and capacity; however, independent air supply means is generally safer. Furthermore, it will be clear that the described assembly can be used for applications other than in hospitals.
We claim: 1. An assembly for isolating a patient in a dust-free manner from the environment comprising, in combination a rectangular framework assembly to be positioned on the floor of a room; dust filtering means positioned adjacent one end of said framework assembly; a chamber supported by said framework assembly and having inside dimensions sufficiently large to accommodate a bed for the patient and provide nursing space adjacent the bed, said chamber including top and side walls attached to said framework assembly, at least one of said side walls being transparent and said top and side walls being joined together, as well as said side walls being joined to the floor, in a dust-free manner,
a rear wall which is formed substantially entirely by said dust filtering means, and
a closeable front wall opposite to said rear wall, said front wall being arranged so that, when in a closed position, an air discharge opening is provided near the floor and is further arranged so that, when in an open position, an access opening is provided permitting personnel to enter and leave said chamber; and
air supply means for introducing air into one end of said chamber through said dust filtering means and for directing substantially horizontal and non-tur bulent air flow substantially across the entire height and width of said chamber to be discharged therefrom through the opposite end, the flow rate of the filtered air being sufficient to prevent the entrance of dust through said discharge opening and said access opening, when said front wall is in a closed and open position, respectfully, and further sufficient to blow away dust introduced by personnel entering through said access opening.
2. A combination according to claim I wherein said dust filtering means is detachably connected to said framework assembly and said framework assembly is demountable.
3. The combination according to claim 1 wherein said front wall is a door means for closing said access opening which is hingeably mounted to the upper portion of said framework assembly, the lower edge of said door means being spaced vertically from the floor to provide said discharge opening when in the closed position.
4. The combination according to claim 3 wherein said air supply means is capable of providing air flow at two different operating levels, the air flow at a first level being sufficient to prevent dust from entering said chamber, when said door means is in the closed position, and the air flow at the second level being sufficient to blow away dust from personnel entering said chamber through said access opening, when said door is in an open position; and
switching means cooperating with said door means and said air supply means for switching said air supply means to and from said first and second operating levels depending upon the position of said door means.
5. The combination according to claim 1 wherein said side walls are sheets of plastic material which are mounted to said framework and said dust filtering means in a dust-proof manner.
6. The combination according to claim 1 wherein the side, top and bottom walls of said chamber are formed from a tubular, flexible, plastic duct which is suspended from said framework assembly with the bottom wall covering the floor inside said framework assembly, the opposite ends of said duct being attached to said dust filtering means and said front wall, respectively, in a dust-proof manner.
7. The combination according to claim 6 including longitudinal pockets provided in at least the upper portion of said duct for receiving an elongated suspension bar; and
means for resiliently suspending said suspension bars to said framework assembly.
8. The combination according to claim 1 wherein at least one of said side walls includes a closeable transfer opening.
9. The combination according to claim 7 wherein the end portion of said duct adjacent to said dust filtering means includes a pocket for receiving a tensioning string means; and
said dust filtering means includes a rim for receiving said tensioning string means.
10. The combination according to claim 1 including closure means providing an opening into said chamber, said closure means comprising a length of tubular flexible plastic material surrounding this opening, each of the opposite end portions of said tubular material being mounted on a substantially rigid hoop whereby an intermediate portion of said tubular material can be pinched to close said opening by relative rotation of said hoops.
ll. The assembly according to claim 1 wherein at least one of said side walls includes an elastically deformable portion.