Patent Application
20160096135
1. Field
The invention generally relates to an access door that includes a scanning mechanism for a containment system, a containment system having the same, and a method for leak testing a filter installed in the containment system.
2. Description of the Related Art
Containment systems are relied upon in lab testing the most toxic and virulent chemicals, agents, viruses, and organisms, each potential leak point represents a source for a potential catastrophic biohazard release that could expose technicians and/or the surrounding environment.
Isolation dampers 114 are located upstream and downstream of the housing 102, the upstream section 110, and downstream test section 112. The dampers 114 allow the containment system 100 to be sealed air-tight during system decontamination. Transitions 120 are disposed between the isolation dampers 114 and other components of the containment system 100 to improve airflow. The dampers 114 may be bolted or welded to the transitions 120. Additional ductwork 122 may be disposed between the dampers 114 and the transitions 120.
The upstream section 110 is utilized for the introduction of an aerosol challenge upstream of the filter 106 and for the measurement of upstream challenge concentration. Conventional upstream sections 110 typically include baffles to achieve adequate aerosol mixing such that testing may be performed to ANSI, IEST or other standard. The filter 106 disposed in the housing 102 may be an intermediate efficiency filter, a HEPA filter, HEGA filter and/or filter selected for a specific application. It is contemplated that the filter 106 may be a panel filter, v-bank filter or other type of filter configuration.
The downstream test section 112 is access the downstream side of the filter 106 for conduct scan testing and validation of the HEPA filter(s) to determine the location and size of any leaks in the filter(s). With the downstream test section access door 116 removed, a technician may access to the downstream side of the filter 106 for testing. For example, the technician may to manually scan the filter 106 with a probe 108 coupled to test equipment 130, such as a photometer, particle counter or other suitable filter leak or efficiency testing device, through the downstream test section 112 when the downstream test section access door 116 is removed.
A bio-isolation bag with integral gloves (not shown) is generally coupled to a bagging ring 132 extending outward from the housing 102. The test section access door 116 encloses the bagging ring 132 when sealing the downstream test section 112. The bio-isolation bag, manufactured from PVC or other suitable material, has an opening containing an elastic cord or o-ring that is capable of stretching sufficiently to slide over the outside circumference of the bagging ring 132. The cord fits securely against the bagging ring and keeps the bag attached to the containment system 100. The bag essentially forms a boundary between the contaminated interior of the containment system and technicians performing service work from the exterior of the housing 102. The bag may be utilized to position the probe 108 during testing of the filter 106 disposed in the containment system 100.
However, each time the downstream test section access door 116 is opened to test the filter 106, the risk for potential exposure of biohazards within the housing 102 increased. Additionally, installation of a new integrated automatic scanning mechanism is very costly. Moreover, upgrading from a manual bag with gloves to an automated integrated scanning probe 108 permanently disposed in the housing 102 may require replacement of the entire containment system 100.
Thus, there is a need for an improved method of scanning the filter of a containment system without risk of exposure to contaminants, and for an improved apparatus for scanning a filter in a containment system.
An access door that includes a scanning mechanism for a containment system, a containment system having the same, and a method for leak testing a filter installed in the containment system are described herein. In one embodiment, a containment system is disclosed that includes a housing having a downstream test section access port selectively sealed by a downstream test section access door. A displacement assembly is coupled to the downstream test section access door and is operable to move a plurality of probes disposed in the housing relative to the test section access door.
In another embodiment, a downstream test section access door is provided that includes a door assembly configured to selectively seal a containment system access port. A displacement assembly is coupled to the test section access door. The displacement assembly is operable to move a plurality of probes configured to obtain air samples relative to the test section access door.
In yet another embodiment, a method for testing a filter disposed in a containment system is provided that includes flowing air into the containment system and through a filter disposed in the containment system, and scanning the filter with a plurality of probes mounted to a door of the containment housing.
In still another embodiment, a containment system is provided that includes a housing configured to hold a filter in a position that separates an upstream section from a downstream test section. The housing includes a filter access port for replacing a filter disposed in the housing, and downstream test section access port communicating with the downstream test section. A downstream test section access door is provided that is configured to selectively seal the downstream test section access port. A displacement assembly is disposed in the housing. A plurality of probes are disposed in the downstream test section which are non-intrusively displaceable by the displacement assembly. A filter access door is provided that is configured to selectively seal the filter access port. A plurality of sample ports are formed through the downstream test section access door. The sample ports are coupled to the probes by tubing.
The accompanying drawings, which are incorporated in and constitute a part of the specification, schematically illustrate the present invention and, together with the general description given above and the detailed description given below, serve to explain the principles of the invention
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized in other embodiments without specific recitation.
The housing 280 includes an upstream section 216, a filter section 218, and a downstream test section 220. The upstream section 216 is separated from the downstream test section 220 by the filter section 218. The upstream section 216 is connected to upstream ductwork 202. The upstream ductwork 202 may include an air inlet duct 204, a transition 206, a damper 208, and optional ductwork 210 connecting the damper 208 to the transition 206. The downstream test section 220 is connected to downstream ductwork 212. The downstream ductwork 212 comprises an air outlet duct 214, a transition 206, a damper 208, and optional ductwork 210. Optional ductwork 210 may connect the damper 208 to the transition 206. The dampers 208, located in both the upstream ductwork 202 and the downstream ductwork 212 of the housing 280 allow the containment system 200 to be sealed air-tight at the air inlet duct 204 and the air outlet duct 214 of the containment system 200 during system decontamination. The dampers 208 may be welded or bolted to the transitions 206.
The upstream ductwork 202 is utilized during normal filtering operations to allow unfiltered air to enter the containment system 200. Once the air flows into the upstream ductwork 202, it passes through the upstream section 216 and into the filter section 218. The filter section 218 includes a filter holder 222 adjacent to a filter access port 226. The filter holder 222 is configured to hold and seal a filter 224 to the filter section 218 in a manner that causes air flowing through the housing 280 to flow through the filter 224.
The filter 224 may be accessed through the filter access port 226, which is selectively sealed by a filter access door 228 and a sealing member 229 disposed on a distal end of a lip extending from and circumscribing a plate of the door 228. The sealing member 229 may be a gasket, an o-ring, or other suitable seal. The filter access door 228 may be opened to replace the filter 224 disposed in the housing 280 to facilitate testing of the filter 224 in the containment system 200. The filter 224 may be a HEPA filter or any other suitable filter for use in a containment system 200. It is contemplated that the filter 224 may be a panel filter, v-bank filter, or other type of filter configuration.
After the air flows into the upstream section 216, the air moves through the filter 224, and into the downstream test section 220. The downstream test section 220 comprises a downstream test section access port 258. The downstream test section access port 258 may be selectively sealed by a downstream test section access door 203 of the door assembly 240. The downstream test section access door 203 of the door assembly 240 includes a plate 205 having a circumscribing lip 242. The circumscribing lip 242 is generally long enough to provide clearance for a bagging ring 132 extending from the downstream test section access port 258 of the downstream test section 220. A sealing member 229 is disposed on a distal end of the lip 242 to provide a seal between the door 203 and the downstream test section 220.
The door assembly 240 also includes a displacement assembly 246 and one or more sample ports 254. The displacement assembly 246 is coupled to a scanning mechanism 256. The displacement assembly 246 is operable to move one or more probes 248 of the scanning mechanism 256. Although only a single probe 248 is shown in
The probes 248 are generally configured to allow isokinetic sampling at a predefined filter test velocity. The number and size of the probes 248, along with the range of motion provided by the scanning mechanism 256, are selected to enable the probes 248 to scans the entire downstream face of the filter 224. Accordingly, the probes 248
The probes 248 are coupled to the sample ports 254 so that samples of the air passing through the filter 224 into the downstream test section 220 may be tested to determine if pinhole leaks are present in the filter 224. The probes 248, via the sample ports 254, may be connected to a photometer, particle counter, or other suitable filter testing device 130.
As discussed above, the downstream test section access door assembly 240 may be utilized as a retrofit door kit that will convert a housing 102 of a conventional containment system 100 into a containment system 200 having automatic or non-intrusive manual scanning capabilities. Alternatively, the containment system 200 may include the probe assess door assembly 240 as original equipment direct from a manufacturer or distributor.
As described above, the displacement assembly 246 may be a non-intrusive automatic device configured to displace the probes 248 in a predetermined and/or programmable motion. In another embodiment, the displacement assembly 246 may be a non-intrusive manual assembly configured to displace the probes 248 via manually operated mechanisms. Controls and/or utilities for the displacement assembly 246 may be routed through one or more of the sample ports 254 defined through the door assembly 240 to a control mechanism 260.
Referring now primarily to the sectional side view of
The automatic displacement assembly 302 is coupled to the door 203 of the door assembly 240 such with the door 203 and automatic displacement assembly 302 form an integral assembly that may be readily removed from the housing 280. For example, the door assembly 240 may be fastened to the door assembly 240 in a cantilevered or other manner, for example, using bolts 330. The automatic displacement assembly 302 alternatively may be coupled to an intermediary base member (not shown), with the base member then connected to the door assembly 240.
The automatic displacement assembly 302 comprises a motion mechanism 304. The motion mechanism 304 may comprise one or more of any suitable actuator, robot, X/Y actuator, linear actuator, a stepper or servo motor, a fluid power cylinder, a rod-less cylinder, a chain or belt drive, a rack and pinion gear arrangement, a ball screw, lead screw, acme screw, or other power screw, or other suitable motion generating and/or motion facilitating mechanism.
The motion mechanism 304 shown in
The position of the probes 248 is controlled by an automatic control mechanism 314. The automatic control mechanism 314 may be attached to an exterior 320 of the door assembly 240 or the housing 280. By controlling the motion of the carriage 308, the probes 248 may be selectively positioned to scan the face of the filter 224. The motion mechanism 304 may move in only the X-direction, across the width of the filter 224 utilizing a plurality of probes 248 connected to the carriage 308. The motion mechanism 304 may, alternatively, make use of a single probe 248 and move in both the X and Y directions to effectively scan the filter 224.
The probes 248 are fluidly coupled to respective sample ports 254 by individual tubes 332, one of which is shown in
The manual displacement assembly 402 coupled to the door 203 of the door assembly 240 generally as described above with reference to the displacement assembly 302, for example utilizing bolts 330. The manual displacement assembly 402 alternatively may be cantilevered to a base member (not shown), the base member which is then connected to the door assembly 240.
The manual displacement assembly 402 comprises a motion mechanism 404 which is operable to move the probes 426 without opening the door 203. In one embodiment, the motion mechanism 404 sealably penetrates the plate 205 of the door 203 through a bearing 436. The bearing 436 allow a rod 406 of the motion mechanism 404 to move axially. A handle 414 may be coupled to the rod 406 to provide an interface for a technician to more easily and precisely operate (i.e., displace) the probes 248 using the rod 406.
The rod 406 has the scanning mechanism 410 fixed thereto. Thus, as the rod 406 is displaced axially, the scanning mechanism 410 also moves axially. The probes 248 are coupled to the scanning mechanism 410. Although a single probe 248 is shown in
Thus, the position of the probes 426 is controlled from the exterior of the door assembly 240 using the portion of the rod 406 that extends through the door 203. Although the motion mechanism 404 is illustrated as a slideable rod 406, the manual motion mechanism 404 may be in the form of a manually operated actuator, such as a ball or lead screw, which moves a carriage 408 in the X-direction to move the plurality of probes 248 across the filter 224. Alternatively, the manual displacement assembly 402 may move the probes 248 in both the X and Y directions to effectively scan the face of the filter 224. By controlling the motion of the carriage 408, the probes 426 may be selectively positioned to scan the face of the filter 224.
Referring back to
In other embodiments, the displacement assembly 246 and scanning mechanism 256 may be coupled to the bagging ring 132 or to other locations within the housing 280. In other embodiment, the displacement assembly 246 and scanning mechanism 256 may include adjustable mounting elements to enable the displacement assembly 246 and scanning mechanism 256 to be passed through the filter access port 226 or downstream test section access port 258, and adjusted to a size that tightly fits across the sectional area of the downstream test section 220. In such embodiments, the sample ports 254 remain disposed through the door 203 of the door assembly 240 so that non-intrusive scanning capabilities may be added to convention containment systems without having to form additional holes through the housing 280 to facilitate coupling the probes 248 to the test equipment 130 without having to access the interior of the housing 280.
This application claims benefit of U.S. Provisional Application Ser. No. 62/059,845, filed Oct. 3, 2014 (Attorney Docket No. CMFL/115USL), of which is incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62059845 | Oct 2014 | US |
