why dont people use these? there not that expensive..
clowntown said:I think I asked this question before without getting a response, but... what purpose does the outer shell serve, exactly? Of course protecting the arc element from dust, small pieces of debris, etc... but why the many different shapes and sizes?
From the size of the outer shell of the 1500w it would almost suggest that it partly serves to limit how close any object can safely get to it... but I just have a feeling that's not it since I don't see manufacturers wasting the extra glass, manufacturing resources, and logistics resources for that feature...
This is not true, at least on your typical MH / HPS HID bulbs. (It is true in fluorescent tubes, however.) Additionally, MH / HPS does not use a resistance filament (like that of halogen / incandescent) to provide light, so this "burn out in a few milliseconds" doesn't really apply.PharmaCan said:The glass also acts to keep the bulb airtight. There's either a vacuum (no air) or perhaps some type of inert gas inside the bulb, but no oxygen. If there were oxygen, the bulb would burn out in a few milliseconds.
[1000w mh]1000bulbs.com said:BT56 Bulb - E39 Mogul Base
1000bulbs.com said:BT56 Bulb - E39 Mogul Base
good of you to point that out. i didnt know, just looked ITS TRUE!clowntown said:This is not true, at least on your typical MH / HPS HID bulbs. (It is true in fluorescent tubes, however.) Additionally, MH / HPS does not use a resistance filament (like that of halogen / incandescent) to provide light, so this "burn out in a few milliseconds" doesn't really apply.
The glass shell does not provide a vacuum, and is filled with the surrounding air. Take a look at the base; on most bulbs, there are holes in the resin or ceramic separating the +/-, which allows air to easily flow from inside and outside the bulb. I think a particularly good example are EYE Hortilux bulbs... where the white ceramic has two obvious holes.
The arc tube, on the other hand, is air-tight and possibly in a vacuum filled with noble gases & metals.
For sure; but why so many different sizes and shapes? For instance... you can get a 1000w MH bulb in maybe 3 or 4, possibly more glass sizes, even from the same manufacturer! I have two 600w MH bulbs... one has a cylindrical, tubular shell like a HPS bulb, except with a slightly larger diameter "pregnant bubble" in the center where the arc tube is; the other one has a much larger shell, similar to that of an EYE Hortilux Blue. And I know for sure I've seen even different glass sizes / shapes yet. What difference does it make?DIGITALHIPPY said:the glass provides a protective cover. <-- my guess
my 600W MH conversion is like that, or maybe thats the glass envelope that sunmaster uses. or for that type of bulb. its more about the type i noticed. although there is veriance. probably temps dosent it need a certin temp just to create the spark? yet if its too hot it might need to cool.clowntown said:For sure; but why so many different sizes and shapes? For instance... you can get a 1000w MH bulb in maybe 3 or 4, possibly more glass sizes, even from the same manufacturer! I have two 600w MH bulbs... one has a cylindrical, tubular shell like a HPS bulb, except with a slightly larger diameter "pregnant bubble" in the center where the arc tube is; the other one has a much larger shell, similar to that of an EYE Hortilux Blue. And I know for sure I've seen even different glass sizes / shapes yet. What difference does it make?
clowntown said:I think I asked this question before without getting a response, but... what purpose does the outer shell serve, exactly? Of course protecting the arc element from dust, small pieces of debris, etc... but why the many different shapes and sizes?
From the size of the outer shell of the 1500w it would almost suggest that it partly serves to limit how close any object can safely get to it... but I just have a feeling that's not it since I don't see manufacturers wasting the extra glass, manufacturing resources, and logistics resources for that feature...