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What angle limits should apply to Graham condensers?
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Moshe Rakhman
What angle limits should apply to Graham condensers?
Your reasoning seems sound. For myself, I wonder why anyone would want to use this type of condenser at all. It has a very small bore which reduces the effective surface area. There are a number of other (better) types of condensers to choose from. Was in the lab for 20 years and never found a reason to use this type of condenser.
Your reasoning seems sound. For myself, I wonder why anyone would want to use this type of condenser at all. It has a very small bore which reduces the effective surface area. There are a number of other (better) types of condensers to choose from. Was in the lab for 20 years and never found a reason to use this type of condenser.
I came here through the VLQ queue. While I believe this answer has enough quality not to be treated with the trash we deal with in this queue, I think you should be a little bit more elaborate. More
Maybe theyre only used for photos (because they look so neat)? The small bore does seem problematic, but in simple terms of effective surface area my guess is the coiling actually More
As far as I can tell, the main reason that graham condensers are shown in near horizontal position is because the setup required to put it properly in a vertical position looks odd to the untrained eye, and requires quite a tall support. The boiling flask, heat source, and so on are elevated as high or higher than the top of the condenser.
The Graham is really only useful as a condenser in the vertical position, and even then, it will tend to "spit" as condensate traps gas above it. To my knowledge it is almost exclusively used in vacuum distillation, for that reason. In spite of numerous drawbacks, it does put a great deal of coolant around the coil. As mentioned, it would be downright daft to use this as a reflux column.
Why this very mediocre piece of glassware should be so common (about half of all distillation apparatus kits seem come with these), is beyond me. Even a plain Liebig condenser is of greater value for any common use that a graham might be used for (vacuum distillation aside). The technique for making graham condensers (to outward appearances) seems like it would be extremely similar to that for making coil condensers, which are far, far more useful, both as reflux columns and distillation condensers, so why the Graham would be so much cheaper is beyond me.
As far as I can tell, the main reason that graham condensers are shown in near horizontal position is because the setup required to put it properly in a vertical position looks odd to the untrained eye, and requires quite a tall support. The boiling flask, heat source, and so on are elevated as high or higher than the top of the condenser.
The Graham is really only useful as a condenser in the vertical position, and even then, it will tend to "spit" as condensate traps gas above it. To my knowledge it is almost exclusively used in vacuum distillation, for that reason. In spite of numerous drawbacks, it does put a great deal of coolant around the coil. As mentioned, it would be downright daft to use this as a reflux column.
Why this very mediocre piece of glassware should be so common (about half of all distillation apparatus kits seem come with these), is beyond me. Even a plain Liebig condenser is of greater value for any common use that a graham might be used for (vacuum distillation aside). The technique for making graham condensers (to outward appearances) seems like it would be extremely similar to that for making coil condensers, which are far, far more useful, both as reflux columns and distillation condensers, so why the Graham would be so much cheaper is beyond me.
I have no idea why there are so many photos showing Graham condensers in a non-vertical position. Maybe just because they look so cool and photos tend to be landscape. The only time that might be safe is if there were a vacuum pulling to the collection side.
Graham condensers should be used vertically, precisely for the reasons you stated: Particularly because otherwise they will bubble, bump, and potentially explode.
I have no idea why there are so many photos showing Graham condensers in a non-vertical position. Maybe just because they look so cool and photos tend to be landscape. The only time that might be safe is if there were a vacuum pulling to the collection side.
Graham condensers should be used vertically, precisely for the reasons you stated: Particularly because otherwise they will bubble, bump, and potentially explode.
One might add that for non-vertical use, the plain old Liebig-type is the only suitable choice. I wonder why anyone calls this Graham-thing a condenser, its just a cooler.More
Your reasoning seems sound. For myself, I wonder why anyone would want to use this type of condenser at all. It has a very small bore which reduces the effective surface area. There are a number of other (better) types of condensers to choose from. Was in the lab for 20 years and never found a reason to use this type of condenser.
Your reasoning seems sound. For myself, I wonder why anyone would want to use this type of condenser at all. It has a very small bore which reduces the effective surface area. There are a number of other (better) types of condensers to choose from. Was in the lab for 20 years and never found a reason to use this type of condenser.
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As far as I can tell, the main reason that graham condensers are shown in near horizontal position is because the setup required to put it properly in a vertical position looks odd to the untrained eye, and requires quite a tall support. The boiling flask, heat source, and so on are elevated as high or higher than the top of the condenser.
The Graham is really only useful as a condenser in the vertical position, and even then, it will tend to "spit" as condensate traps gas above it. To my knowledge it is almost exclusively used in vacuum distillation, for that reason. In spite of numerous drawbacks, it does put a great deal of coolant around the coil. As mentioned, it would be downright daft to use this as a reflux column.
Why this very mediocre piece of glassware should be so common (about half of all distillation apparatus kits seem come with these), is beyond me. Even a plain Liebig condenser is of greater value for any common use that a graham might be used for (vacuum distillation aside). The technique for making graham condensers (to outward appearances) seems like it would be extremely similar to that for making coil condensers, which are far, far more useful, both as reflux columns and distillation condensers, so why the Graham would be so much cheaper is beyond me.
As far as I can tell, the main reason that graham condensers are shown in near horizontal position is because the setup required to put it properly in a vertical position looks odd to the untrained eye, and requires quite a tall support. The boiling flask, heat source, and so on are elevated as high or higher than the top of the condenser.
The Graham is really only useful as a condenser in the vertical position, and even then, it will tend to "spit" as condensate traps gas above it. To my knowledge it is almost exclusively used in vacuum distillation, for that reason. In spite of numerous drawbacks, it does put a great deal of coolant around the coil. As mentioned, it would be downright daft to use this as a reflux column.
Why this very mediocre piece of glassware should be so common (about half of all distillation apparatus kits seem come with these), is beyond me. Even a plain Liebig condenser is of greater value for any common use that a graham might be used for (vacuum distillation aside). The technique for making graham condensers (to outward appearances) seems like it would be extremely similar to that for making coil condensers, which are far, far more useful, both as reflux columns and distillation condensers, so why the Graham would be so much cheaper is beyond me.
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I have no idea why there are so many photos showing Graham condensers in a non-vertical position. Maybe just because they look so cool and photos tend to be landscape. The only time that might be safe is if there were a vacuum pulling to the collection side.
Graham condensers should be used vertically, precisely for the reasons you stated: Particularly because otherwise they will bubble, bump, and potentially explode.
I have no idea why there are so many photos showing Graham condensers in a non-vertical position. Maybe just because they look so cool and photos tend to be landscape. The only time that might be safe is if there were a vacuum pulling to the collection side.
Graham condensers should be used vertically, precisely for the reasons you stated: Particularly because otherwise they will bubble, bump, and potentially explode.
More
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