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Glove Box Maintenance And Troubleshooting

The Ossila Glove Box (or glovebox) uses automatic purging and programmable leak tests making it easy to maintain an inert environment. However, there are a number of steps that you as the glove box user can take to ensure that the inert atmosphere remains intact. These include performing regular cleaning and maintenance checks, following a standard operating procedure, using the antechamber correctly, and purging as required.

It is also important to be able to quickly identify, troubleshoot, and fix problems as they occur. Even if your glove box is properly maintained, leaks and other issues can occur during normal usage.

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Glove Box Maintenance

To work safely and efficiently in a glove box, you need well defined procedures and scheduled upkeep. This will help you reduce the risk of accidental exposures, and will ensure that you are using your glove box time effectively.

The following tips should help you to set up a good standard of practice for your laboratory.

Glove box cleaning and maintenance checks

It is good practice to schedule regular glove box cleaning and check-in sessions. For small glove boxes, every 1-3 months will generally be sufficient.

When doing a routine check-in:

  1. Check if the hands of the gloves are dirty or marked.
    If they are, wipe them down with an appropriate solvent. We recommend isopropanol or ethanol for butyl rubber glove box gloves. If this does not clean the gloves sufficiently, you may need to replace them.
  2. Once the gloves are clean, place a pair of XL nitrile gloves over the top of the glove box gloves. This will prevent further solvent damage during cleaning, prolonging their lifetime.
  3. Wipe down the surfaces and walls of the glove box using an appropriate solvent. Make sure you collect any residue powders or contaminants which may have accumulated.
  4. Use isopropanol to remove marks from the inside of the glove box screen.
  5. Remove and dispose of all cleaning materials (including the nitrile gloves) and other waste from the glove box via the antechamber.
  6. Begin a short timed purge within the glove box to remove any residual solvent vapours.
  7. Do a visual check of the glove box gloves and any O-ring seals, making a note of any small cracks or tears. Even if small holes have not affected glove box functionality yet, they may do in the future. Tears in the gloves can be temporarily covered with black electrical tape.
  8. Check the sensor boards are functioning properly by checking the log book for fluctuating O2 levels or by inspecting the sensors visually. For the Ossila Glove Box, the O2 and H2O data can be extracted using the USB connector.
  9. Perform a leak test to ensure all seals are intact. 
  10. Check your nitrogen or argon supply for leaks to ensure you don't run out of inert gas. 

Some glove boxes use a recirculation system which involves purifying materials (molecular sieves/catalysts). These materials will become saturated with moisture and oxygen over time, and will therefore need to be "dried out" every so often. This is done by flushing the system with a mix of hydrogen and nitrogen at high temperatures. This is known as a glove box regeneration.

How frequently you need to perform a glove box regeneration depends entirely on how much you use your glove box. You may need to do a regeneration if the oxygen sensors are consistently reading values of >1ppm.

Standard Operating Procedure

Working safely within an inert glove box requires the co-operation of everyone who uses it. For this reason, we recommend outlining a standard operating procedure for your laboratory. All lab users should agree to follow this procedure before being granted access to the glove box.

When entering a glove box

It is important to limit the exposure of the internal chamber to aqueous solutions or materials which may contain moisture (cleanroom tissue or hygroscopic materials that have been exposed to air). There are specific measures which you should take if you want to bring these types of materials into your glove box.

  • Thoroughly degas porous or hydroscopic materials (cleanroom tissue, paper, cloth, etc) before bringing them in to the main glove box chamber. Normal antechamber purging may not be enough to thoroughly remove moisture. Degas any cleanroom tissue, paper or cloth under vacuum for several hours before bringing it into the glove box.
  • If a solvent or material was sealed under inert conditions and has not been opened in air since, you can bring it into the glove box via the antechamber purging procedure.
  • Degas hygroscopic or absorbent powders that have been exposed to air before bringing them into the glove box. We recommend doing this for a significant period of time (ideally overnight) in a vacuum oven, or under vacuum/drying conditions.
  • For all other small vials of materials and solutions that have been exposed to air, you can cycle as normal. 
  • Ensure all glassware and equipment is dry before entering the glove box. 

We have created the following flow chart to help you decide on the appropriate steps to take before taking things into the glove box.

Bringing supplies into the Glove Box

Additionally, it is vital to always make sure the O2 and H2O levels within the antechamber are sufficiently low before bringing anything into the glove box.

It is a good idea to always cycle the antechamber before opening the door into the main glove box, even if the O2 and H2O readings are low. This creates a good habit, which can help you avoid accidentally exposing the glove box to air in the future.

When working within a glove box 

The following are generally good practices for working in any glove box environment.

  • Push hands into the glove box slowly. Quickly forcing your hands into the glove box will cause the chamber pressure to change rapidly. This can cause bottles or samples to fall over, and puts extra strain on the glove box gloves. 
  • Wear appropriate PPE while working in the glove box. If you are working with harmful substances, you may risk exposure if there is a tear in the gloves. Additionally, constant contact with skin may reduce the gloves lifetime. For these reasons, we suggest that you wear a lab coat and nitrile gloves whenever using a glove box. 
  • If you are using organic solvents, you must regularly purge the glove box. Solvent vapours will quickly build up in a glove box if solutions are left open. Prolonged exposure to these vapours could damage the sensor board, the O-ring seals, and the gloves. Additionally, harmful solvent vapours from the main chamber could be released into the room when you take things out through the antechamber. Wherever possible, limit chamber exposure to organic solvents (e.g. close solution bottles whenever possible), and regularly purge the glove box if solutions are open for a significant period.
  • Remove all jewellery and watches before entering the glove box, as these may tear the gloves. Be careful to avoid puncturing the glove box gloves. 
  • Constantly monitor moisture and O2 levels during usage. Any major fluctuations in these levels or compromises in the inert environment should be logged and counteracted as soon as possible. 
  • If you suspect a leak at any place in the glove box, check! Use leak spray (or soapy water) to detect the presence of leaks.
  • Reduced oxygen concentration within a confined space can lead to severe health effects. Check with the appropriate body for guidelines on working with asphyxiating gases. Oxygen depletion alarms can be installed in rooms where there is a pressurized nitrogen source to alert users if the oxygen concentration in the room begins to drop. 

Glove Box Golden Rules

  1. Watch the oxygen and humidity levels! Frequently log the O2 and H2O levels within the main chamber. This will help you identify problems quickly and could save your experiment.

  2. Always check the antechamber O2 and H2O levels before opening to the main chamber. 

  3. Optimize your work space. Space is limited in a glove box, so it is important to keep the glove box floor as clean as possible. Remove waste after each use and perform a quick purge if you have been working with solvents. 

How to use an antechamber

In relation to laboratory glove boxes, antechambers are small, isolated compartments through which you can move small items in and out of the main chamber. This smaller vessel can be exposed to atmosphere more often than the main chamber as it will take much less time to achieve inert conditions.

In large glove boxes, the antechamber is most likely connected to a vacuum pump. After being exposed to ambient conditions, the air is evacuated out and refilled with nitrogen. After this is "cycled" several times, the antechamber can be opened to main glove box chamber.

Our glove box system features an automated purge cycle. Once started, this cycle circulates nitrogen through the antechamber until oxygen and moisture levels are consistently below set values. This is the same procedure that is used for main chamber and should reduce the chances of accidentally exposing ambient oxygen or humidity.

Always check oxygen and humidity levels before exposing the antechamber to the main glove box.

Ossila Glove Box antechamber
Glove Box antechamber

To take samples into the Ossila Glove Box: 

  • First, ensure that the door between the main chamber and the antechamber is closed.
  • Open the door between the antechamber and outside, and place your materials or equipment into the antechamber. Shut the antechamber door.
  • Go to the antechamber splash page, and set desired O2 and H2O levels.
  • Check both doors are shut, then press the "Start Purge" button on the control panel.
  • Once the purge is complete, you can safely move your items into the main chamber of the glove box.

Taking samples out of the glove box requires a similar process.

  • Check the O2 and H2O levels within the antechamber as per the golden rules.
  • If these are higher than the desired levels, or at least not matching those in the main glove box, set the antechamber O2 and H2O levels and press "Start Purge". 
  • Once the antechamber purge cycle has finished, place the items from the glove box main chamber into the antechamber and close the internal door. You can then take the items straight out into ambient conditions. However, if you have been processing with hazardous solvents, it is often a good idea to purge for a few seconds before opening the glove box.  
  • It is good practice to cycle the antechamber at least once directly after it has been exposed to air. This reduces the chances of accidentally flooding the glove box with oxygen. 

Glove Box Purging

All glove boxes should have systems in place to maintain a constant inert environment. The Ossila Glove Box has an automated purging system where action is taken if the O2 and H2O levels drop below their set values.

First, nitrogen is pushed into the system for a few seconds until an overpressure is reached. Then, some of the internal gas from the main chamber is extracted through the outlet for a few seconds. This process repeats until enough nitrogen has been cycled through the chamber, and the oxygen and moisture levels are sufficiently low.

Automated Glove Box purge mechanism

There are times where additional intervention is needed. For example, when working with organic solvents, solvent vapours can quickly build up within the main chamber. This can damage the filters, gloves or sensors in the glove box, and can affect your experiment. In these situations, we recommend you perform a nitrogen "Quick Purge". 

To do a quick purge, select the circulation ("Circ") icon on the main glove box page. You will get an option to set a time and number of cycles. Once these are set, simply highlight the "Circ"  and press "Start Purge".

When quick purging, the system will drive nitrogen into the chamber for a few seconds, then extract internal gas out of the chamber. This is the same process that is used in the automated purge. There will then be a short 30 second rest period with no extraction or purging. This allows the system to acclimate as the O2 and H2O levels to adjust. This process repeats for the time set (e.g. for 300 seconds), and then will repeat for the number of durations chosen.  

Positive vs negative pressure glove boxes

Inert atmosphere glove boxes should be maintained at a slight positive pressure. This ensures that if there is a leak in the glove box, the internal environment will be forced out, rather than air and moisture being sucked in. We recommend maintaining the Ossila Glove Box at 1-2 mBar over ambient pressure whenever you are using it.

Leak tests however should be preformed at a higher mBar. This is because when you are performing a leak test, you are trying to highlight any potential leaks. This is also true when trying to identify the source of a leak. For leak investigation, we recommend a pressure of 3-5 mBar.

Inert Atmosphere Glove Box

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Is there a leak in the glove box?

Leaks will compromise the inert environment of a glove box, and potentially ruin your experiment. Small leaks may lead to a slow increase of contaminants over time. Large leaks will prevent your glove box from functioning at all, and can create a dangerous working environment.

There are some signs that could indicate there is a leak in your glove box system. These include:
  • Continuously increasing O2 and H2O levels when the glove box is sealed.
  • If the glove box is struggling to maintain pressure.
  • If the glove box is using a larger amount of nitrogen than normal.
  • If using solvents, a smell of solvent in the room can be an indication of a leak. However, this could also be through movement in and out of the antechamber.
  • If the gloves are deflated and pressure is low, there is a serious leak.

What to do if you suspect a leak

There are five basic steps which you should take if you suspect that there is a leak in your glove box:

  1. Use the automated Ossila Leak Test, or alternative leak test, to confirm the presence of a leak.
  2. Visually inspect for tears in the gloves or O-ring seals on the antechamber door. If there is a tear on one of the gloves, it is likely that the O2 levels will increase when the gloves are squeezed.
  3. For the Ossila Glove Box, check that all the bolts around the window are sufficiently tight.
  4. Spray down the outside of the glove box with soapy water and circulate nitrogen through the system. The over pressure will cause bubbles to form wherever nitrogen is escaping from the glove box.
  5. If none of these steps solve the issue, it might be worth disassembling the glove box and ensuring all parts are clean and intact. 

How to replace a glove box glove

Glove box gloves must be flexible and relatively thin to allow movement within the main chamber. This will be the most vulnerable exposure point to air and moisture as small holes can easily occur here. If you find any tears, temporarily cover them with black tape.

Glove box glove with small hole
Glove box glove holes can be temporarily covered with black tape

To replace a glove without exposing the internal environment to air, follow these steps:

1. Push the old glove into the glove box. You need to stop the system purging to allow the gloves to be pushed in and internal pressure to lower.

Glove box glove - push gloves into glove box
Push old glove into the glove box

2. Once the glove is mostly in, remove one of the O-rings, and then roll the glove back over the second O-ring as shown below. Make sure that the glove does not roll off the port completely.

Glove box glove - remove one O-ring
Remove one O-ring
Glove box glove - roll glove over O-ring
Roll the glove lip back over the O-ring

3. Compress the new glove as much as possible to ensure that minimal air is trapped in it and place it over the port and the old glove 

Glove box glove - compress glove
Compress the new glove
Glove box glove -  put new glove on
Place the new glove over the old glove and O-ring

4. Place the O-ring on top of the new glove to secure it in place.

Glove box glove - new glove in place
New glove over old glove
Glove box glove - o-ring secures glove
Place the other O-ring on top of the new glove

5. From inside the main glove box chamber, carefully pull the old glove off the port into the main chamber of the glove box. Use the hand outside of the glove box to ease this movement, and to ensure that the new glove stays on the port. This is a little difficult so proceed carefully.

Glove box glove - pull old glove through
Pull the old glove into the glove box main chamber

6. Once the old glove and O-ring are in the main chamber, these can be removed through the antechamber.

Glove box glove - take glove out of chamber
Take the old glove out using the antechamber

7. Place the final O-ring on the port, to secure the new glove.

Glove box glove - final o-ring secures glove
Place the new O-ring over the new glove

How to Do a Leak Test

A leak test involves raising the glove box to extreme positive or negative pressure. Then, the rate of change of pressure is measured over a period of time. This will give you a leak rate, which will indicate how well-sealed your glove box is. Our glove box has an automated leak test programme to make this process as easy as possible. 

To perform a leak test on your glove box, go to the "Leakage Test" section of the Menu.

Ossila glove box leak test
Ossila Glove Box leakage test

Here, you can define how long the leak test is performed for and at what pressure it will be held. We recommend holding the glove box at 5 mBar overpressure for at least 5 minutes. 

Ossila glove box leak test settings
Leakage test at 5 mBar

The glove box will first reach that overpressure then measure pressure of the system over the defined period of time. There may be a leak in the system if the leakage rate is <0.25% volume per hour (vol/hour). This data can then be extracted using via a USB connection.

If this leakage test is successful, then there are no significant leaks in your glove box. If unsuccessful, take further steps to identify the source of the leak.

How to Protect Samples Outside of an Inert Environment

Glove boxes are very useful when working with materials that are sensitive to ambient conditions. However, you will probably need to take your samples out of the inert environment at some point. This may be to characterise samples or to transfer them to another location. Example situations may include:

  • Travelling to a facility or measurement centre with ready made air sensitive samples. 
  • Sending samples to be measured at other facilities.
  • Transferring samples from one lab to another 
  • Storage of samples over long time periods
  • Taking air sensitive samples to be measured or imaged.

There are several methods that can be used to take sensitive samples out of a glove box. If the sample is a thin film, it could be encapsulated. The combination of UV-curable epoxy with a glass cover slide provides robust protection of any thin film sample. However, it is important to ensure that the process of encapsulation does not damage the sample. 

If the material cannot be encapsulated, you might just have to limit the amount of time your sample spends in air. In this case, you can seal materials and samples in a vessel inside the glove box to create a small, temporary inert environment. These sealing vessels can include screw-lid bottles, sealing in glass ampules or in vacuum sealed bags. In desperate situations, zip lock bags will provide some protection against ambient conditions over a short time frame. The sealing method you use depends entirely on your situation and your sample.

How to reduce static in the glove box

When weighing or decanting powder materials in a glove box, electrostatic charge can become a problem. The Ossila Glove Box is grounded, which should help significantly reduce issues with static charge. If you still find issues with static build up (such as on glass substrates), we can recommend wearing nitrile gloves over the butyl rubber gloves. Additionally, glove box ionizers or anti-static guns can be used to reduce the amount of static in a glove box.

Can you handle powders in the glove box?

Handling powders in a glove box can be tricky. Problems with electrostatic charge may be an issue, and although there are actions which can be taken to reduce this, it is hard to eliminate completely. Additionally, pressure fluctuations inside the glove box can cause bottles to fall over. Therefore, it is very important when working with powders to push hands into the glove box very slowly if there are any open bottles or exposed powders.

It is possible to weigh powders inside the glove box, but it is very difficult, as pressure fluctuations can cause inconsistent measurements. It is important if you are weighing inside the glove box to keep your hands inside as much as possible. Alternatively, it may be a good idea to: 

  1. Weigh an empty bottle outside the glove box and record the weight. 
  2. Take this bottle into the glove box and decant a small amount of material into it inside the glove box. 
  3. Take this filled bottle out of the glove box and weigh it again. 

This ensures that that the powder is accurately weighed without being exposed to ambient conditions. From this, the amount of solvent needed to dissolve this powder can be calculated.

Glove Box O2/H2O Levels Increasing

If the moisture and oxygen levels within the glove box are gradually increasing, begin by checking that the circulation system is functioning. 

If using an Ossila Glove Box, check the automated purge system. To do so, go to the settings page and check that automatic purging is "Active", not "Inactive". To activate, simply press "Start Purge" while on the settings page. This automated purge can be turned off by pressing "Stop Purge" on the settings page. 

Ossila Glove Box purge inactive
Glove Box purge system when inactive
Ossila Glove Box purge active
Glove Box purge system when active

If the glove box is held at overpressure, a small leak shouldn't cause an increase in O2 or H2O levels. However, it is always worth checking for leaks if the O2 levels are continually rising.

Other factors to consider are:

  • Do the O2/H2O levels increase when opening the glove box antechamber?  If so, it could the antechamber door seal. If the contamination levels increase noticeably when you put your hands into the glove box, there could be a hole in the gloves. 
  • Do the O2/H2O increase when the system is purging? If so, the inlet tubing or nitrogen source may be compromised, allowing oxygen or moisture to enter the glove box. Check along the inlet pipe and at feedthroughs for leaks or holes, and replace the feedthrough or inlet pipe as necessary.
  • If no leak can be located, check the oxygen sensor board. The oxygen sensor may need replacing. The sensor board can become damaged if working with organic solvents or using high temperatures in the glove box. 


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Inert Atmosphere Glove Box

Ossila Glove Box
  • Affordable
  • High Performance
  • Worldwide Shipping

Buy Online £8,500.00

Contributing Authors

  • Mary O'Kane
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