The Pressure Control Unit (PCU) is a Type 304 stainless steel portable HEPA ventilation unit designed to maintain a positive or negative pressure in a flexible or hard sided enclosure such as flexible isolators, small hoods, and glove bags. The filter housings are spun aluminum. The PCU is equipped with a touchscreen Programmable Logic Controller (PLC) and pressure monitoring system.
This small, portable HEPA unit provides a safe, controllable, negative or positive pressure environment to your flexible enclosure or flexible isolator. Other applications include HEPA spot ventilation for engineering controls or situations where variable flow (fan speed) is desired or necessary. The HEPA Filter is flanged to the ventilation unit and can easily be changed using the Bag-In/Bag-Out containment.
The PCU is a highly recommended alternative to the use of HEPA vacuum cleaners as ventilation equipment. Vacuum cleaners can cause damage to flexible isolators due to their powerful suction collapsing or tearing the fabric.
PLC Automatic Control
One way to control pressure is to utilize the PLC “feedback” loop that automatically adjusts fan speed to maintain a preset containment pressure (positive or negative). The other method is to manually set the fan speed to the desired enclosure pressure and manually adjust the speed while the PCU is operating. Depending upon the installed configuration, the blower will either add or exhaust HEPA filtered air from the enclosure until the pressure inside of the enclosure stabilizes at the preset value. Should there be a containment breach, the PCU will attempt to maintain the preset pressure point. The PCU is a highly recommended alternative to the use of HEPA vacuum cleaners as ventilation equipment. Vacuum cleaners can cause damage to flexible isolators due to their powerful suction collapsing or tearing the fabric.
HEPA Filter Options
The PCU can be equipped with a HEPA filter on both the supply and exhaust sides of the blower. It can be operated with either one or two filters installed. The HEPA filters can be installed on the upstream side, the downstream side, or for added protection, double HEPA’s can be installed on both ends. This dual filter configuration allows the PCU to operate in either a positive pressure or a negative pressure mode. With new filters, it is capable of moving 150 cfm with one filter installed, or 110 cfm with both filters installed. Interlocks prevent operation with the filter(s) removed or not properly seated. The PCU is capable of passing a filter penetration test with a new filter installed yielding a 99.95% efficiency @ 0.3 micron level. It is ducted using a 3” diameter connection on both the supply and exhaust nipple connections which are located on the filter housings.
Alarm Options
The PCU has the option of being used with a local or remotely located audible and/or visual alarm. The values of duration and deviation can be adjusted by the user to suit their needs. The alarm is triggered when the desired pressure misses the actual internal pressure for more than a preset time period, indicating a significant containment breach, loaded filters or other non-desired conditions. The alarm is silenced by either pressing an “acknowledged” button on the PCU’s touch screen or when the desired pressure matches the actual internal pressure.
FEATURES:
- Adjustable flow from 0 to 150 CFM under normal operating conditions
- Flow rate up to 175 CFM in breach conditions
- Disposable 10” dia. X 12.25” (including nipple connection) HEPA filter on exhaust and/or supply side
- Capable of double HEPA filtration (included)
- Pressure sensor, displayed on PLC
- 3" diameter inlet/discharge collar
- Continuous duty 48 VDC blower
- 0.4” w.g. @ 75 CFM
- UL/CSA listed electrical components, NEC wiring conformance
- 110/220V 60/50 Hz
- Dry contacts to signal alarm condition
- 50 lbs. (nominal)
- 10.50” long X 12” tall X 10” wide without filters installed