Figure 5: Large Altitude Test Chamber with Operable Acrylic Portal and PC Touch Screen VCC Package

Subject your medical, pharmaceutical, food, electronics, and aerospace products and/or packaging to the minimum or range of pressures that they must survive, and/or operate in, as they are trucked/flown or used around the world at various altitudes. Abbess Instruments has a wide portfolio of Altitude Test systems to suit your needs in addressing DOT and FAA ASTM test requirements: Since altitude, from sea level to space, can be associated with a particular pressure, all our vacuum chambers seen on this website can be described and used as Altitude Test Chambers. Please refer to our Space Simulation Test Systems page for tests requiring space altitudes (pressures ≤10-4 Torr) and active thermal cooling. For the purpose of this page, Abbess defines ‘Altitude Test Systems’ as those systems that simulate altitudes of up to 100,000 ft / 19miles / 30km (pressures ³10-4).


Basic System | Complex System | Typical Performance Data | Upgrade Options

View our Altitude Testing Products 


Basic System

Figure 1: Basic Altitude Test Chamber

Figure 1: Basic Altitude Test Chamber

A basic Altitude Test System (as illustrated in Fig 1) consists of the following:

  • Vacuum Chamber
    – A front or top-loading aluminum cylinder with Acrylic or Aluminum lid.
    Or
    – A front or top-loading Aluminum or SS cube with full Acrylic or metal doors.
  • Analog Pressure Gauge

Do you require manual or automatic operation? Abbess will work with you to customize automation to your process, just as we will work with you to ensure the system configuration meets your production/operational needs: While the most basic system (such as in Fig 1) can be controlled manually (by starting/stopping the pump(s) and opening/closing valves), a Vacuum Cycle Controller (VCC) can be added to automate a) vacuum/hold/vent control functions, and b) vacuum (and thermal) monitoring. Control may be either via panel-mounted buttons and indicators or via a PC with user-specified Graphical User Interface (GUI).  The basic digital VCC will permit a single ‘automatic’ altitude/vacuum set point, whereas full altitude/flight ‘climb & Dive’ profile simulation functionality can be built in to the PC Touch Screen VCC upgrade option.

Where there is limited counter space or large batch sizes, the entire system can be integrated on a cart using identical or mixed-sized, chambers. Since cart mounted systems are shipped turn-key, set-up is minimal. Cart-mounting provides full system mobility and thus flexibility of positioning on your production floor.  Recessing vertical cylinders into the cart provides improved ergonomics of loading/unloading. Mixed-sized inventory? Add optional removable shelving.


Complex System

A complex Altitude Test System consists of several major subsystems: the main chamber; the pumping system; the thermal shroud or plate; and the control system:

 

Figure 2: Complex Altitude Test System (48” Cube) with Thermal Plate, PC Touch Screen, and Mobile Cart: Open and Closed View

Figure 2: Complex Altitude Test System (48” Cube) with Thermal Plate, PC Touch Screen, and Mobile Cart: Open and Closed View

fig3a

Figure 3: Sample PC Touch Screen VCC GUI: Main Screen Showing Real-Time Vacuum and Temperature Measurements.

Chambers can be as large as the ones shown above (in the order of 48” x 48” x 48” or larger). Chambers of all sizes are routinely made so that the walls deflect less than an impressive 1/1000” while under vacuum. Thick walls and strategically placed external ribs are needed to do this – more in the larger chambers. The smallest cube chamber offered is 14”.

Chambers are readily configured to provide product visibility and accessibility:  Large doors, and portals/hatches (Figs 4 & 5) provide optimal accessibility. For our Aluminum and Stainless Steel cube chambers, visually observe your test item (illuminated by optional switchable, in-chamber lighting) through full Acrylic doors (Fig. 1) and/or optional viewports, and operate an optional turntable to bring another item into view.  Use the same, or other viewports, to optically illuminate/test your in vacuum items at your desired wavelengths. Close optional shutters for subsequent light-tight storage or functional testing.  Also see our High-Visibility Vacuum Systems.

 

Altitude Test Chamber pumping systems can be complex, often requiring Turbo pumps in order to bring the expansive chamber down to the required vacuum level … and in a timely fashion . This is so, particularly if operational pressures of ≤10-4 are required. Such pumps attach directly to the chamber and pump through large ports, of around 10” diameter, at speeds of hundreds of cubic feet a minute.

The thermal shroud is a sub-chamber within the chamber finished perhaps in gold (as shown in our Space Simulation Test Systems page) to reflect as much heat as possible back to the Unit Under Test; or dense black to absorb as much heat and light as possible. Shrouds and plates are typically heated/cooled sub-systems covering the large range of -80C to +195C, with liquid N2 being the common choice for cooling.

Monitoring and control of systems are attuned to the customer’s specified process needs which, for “Climb & Dive” and/or thermal profiling, requires a PC Touch Screen package (the panel is shown to the left of Fig. 2, and its GUI in Fig. 3. An example of thermal profiling is given in Fig. 6, and of “Climb & Dive” in Figs. 7-10. Manual and automatic valve operation and pump control are configured to both optimize operation time and assure the proper cycling of vacuum equipment. Abbess and system operators can connect remotely to these PC control systems which, in turn, can be programmed to acquire and log data, and to message operator mobile devices.

fig6

Figure 6: Temperature Profile Example. The above graph shows the action of a mixed ramp ratetemperature profile. The cooling ramp rate is set for 5C/min; the ramp rate going from 30C to 70C is set at 2C/min; and the ramp rate going up from 70 C to 110 C is set at 5C/min. At each target temperature, the system is allowed to ‘soak’ for a preprogrammed time.


Typical Performance Data

The following sample data were taken from 48” cube chambers. Testing is performed on empty, clean chambers at the Abbess Facility in Holliston (188’ elevation).

Typical Performance Summary see Table 1

  • “Climb & Dive” Pressure Profile Examples: in Torr
  • “Climb & Dive” Pressure Profile Example: in Feet
  • Thermal Plate Performance Example
Table 1: Typical Performance Summary
Space Simulation System Performance 48” Cube
Operational Vacuum ≤10-6 Torr For an empty, clean chamber at sea level … over all Temp ranges
Vacuum Ramps Pump Down Ramp:
≤10-5 Torr in ≤ 3 hrs
For an empty, clean chamber at sea level
Vacuum Relief Ramp:
< 3 mins
Deep Space Vacuum Stability Within 1×10-9 Torr over several minutes

Within 0.2×10-7 over 12h 49m

Measured at 10-7 Torr
Thermal Range -150°C to +150°C Of thermal plates
Thermal Ramps Fast Ramp: Over the range -60°C to +100°C heating and cooling
3°C/min Using 22psi LN2 tanks
6°C/min Using 235 psi LN2 tanks
Slow Ramp:
≤1°C/min

Note that a simulated “Climb” in altitude presents as a drop/dive in Torr: i.e. pressure drops as altitude increases.

  • Pressure Dive from 740 Torr to 700 Torr at 50 Torr/min and soak for 1min;
  • Pressure Dive further to 500 Torr at 50 Torr/min and soak for 1 min;
  • Pressure Dive further to 400 Torr at 50 Torr/min and soak for 1 min;
  • Pressure Climb to 500 Torr at 50 Torr/min and soak for 1 min;
  • Pressure Climb further to 600 Torr at 20 Torr/min and soak for 5 min;
  • Pressure Climb further to 740 Torr at 20 Torr/min and soak for 1 min.

“Climb & Dive” Pressure Profile Example: in Feet

Note that a simulated “Climb” in altitude presents as a drop/dive in Torr: i.e. pressure drops as altitude increases.

 

The system operates in Torr; any values the operator inputs as feet are converted by the system for monitoring and control purposes. All ramps are linear in Torr, but non-linear in ft or meters (the average ft or m ramp rates achieved are those set by the operator).

Thermal Plate Performance Example

 

Figure 11: This curve shows cooling from 80C to -55C (setpoints), followed by heating to +100C setpoint.

Figure 11: This curve shows cooling from 80C to -55C (setpoints), followed by heating to +100C setpoint.


Upgrade Options

In summary, a Basic Altitude Test System (as illustrated in Fig 1) consists of the following:

  • Vacuum Chamber
    – A front or top-loading aluminum cylinder with Acrylic or Aluminum lid.
    Or
    – A front or top-loading Aluminum or SS cube with full Acrylic or metal doors.
  • Analog Pressure Gauge

Upgrade options include:

  • Vacuum Pump with Inlet and Exhaust Filters- Optional power and automatic control can be integrated into a Vacuum Cycle Controller (VCC).
  • A Vacuum Cycle Controller (VCC) that can be used to automate some or all of the control functions via panel-mounted buttons and indicators (Fig 2). It will permit a single ‘automatic’ altitude/vacuum set point.
  • A VCC controlled by a PC with a user-specified Graphical User Interface (GUI) operated through a touch-screen (as illustrated in Figs 3 & 4 and in Data-Logged High Vacuum Storage System). This permits: automatic monitoring, data-logging, and vacuum environment display; remote access; and optionally message-sending to operator’s mobile device.
  • Altitude profile simulation functionality can be built in to the PC Touch Screen VCC upgrade option.
  • Process Control Enclosure – Contains components necessary for controlling the system as well as logic and interfaces for the Vacuum Cycle Controller.
    • Process Timer Control
    • Status Indicators – Provide visual indication of system status.
    • Vacuum Cycle Controller – Control ON/OFF buttons, main power switch.
  • Control Valves are required with a VCC:
    • Automatic Vent Valve – Automatic solenoid valve vents air or inert gas purge into chamber based on control input from Vacuum Cycle Controller.
    • Proportional Valve – controls pumping to a certain rate for altitude profile simulation.
  • Digital Pressure Gauge & Controller are required with a VCC
    • Provides pressure display and set point valve control per integral Pressure Transducer data.  Also provides pressure set-point relays that can be used for various system control functions.
  • Mobile cart; or heavy duty in-built casters for the largest systems.
  • Heating and/or cooling thermal plates/shelving and control:
    for heating up to 150C, or 300C) (as illustrated in the Vacuum Oven System).
    and/or for cooling to -150C (as illustrated in the Space Simulation and Thermal Vacuum System).
  • Humidity & control
  • Shelving (passive).
  • Inert gas purge.
  • Circulation fans.
  • Mechanical feedthroughs such as shafts with or without rotation.
  • Electrical feedthroughs for power and signals.
  • Optical ports for optimal transmission of test equipment wavelengths
  • Hold down fixture (often required to keep empty packaging submersed under liquid.
  • Drains, and/or spill trays.
  • Special coatings such as PTFE non-stick coating, FDA-approved
  • Switchable, internal lighting
  • Viewports

Abbess can help you. Successfully test your high-value inventory in our manual or automatic, data-logged or not, single or multi-chambered, Altitude Test systems.