jaymanaa
RIP 1961-2018
Wasn't a hot chassis radio near the bath tube how guys used to get rid of their wives before divorce was the accepted method?
Mercury Rectifiers in a new build, bad idea?
- Thread starter analog addict
- Start date
Wasn't a hot chassis radio near the bath tube how guys used to get rid of their wives before divorce was the accepted method?
Fluorescent light bulb may contain the equivalent of a 83 tube. Big deal. The 83 has a constant 15 volt drop regardless of the current drawn through it (within its ratings). A choke input filter is recommended.
Normally, a separate filament and plate transformer are used with mercury or xenon rectifiers. There is a normal 30 to 60 sec delay for the filament to come up to normal temperature before the HT is applied. If you don't like mercury, use two 3B28 xenon rectifiers in a full wave CT circuit. If you don't care, two 816 or 866A work nicely. A 2.5 volt 10 amp transformer (at least 3 kv insulation) should be used for the 3B28 or 866A when working with HT supplies up to 1.5 kv or so.
You will get the blue glow with the mercury rectifiers (83, 816, or 866A). There is a glow in the 3B28 but it is enclosed in the heat shield and not seen from the outside.
As for breakage, a vented enclosure and a chassis bottom plate will protect tubes from breakage, animals, kids, etc. This should be done anyway since anode voltages can kill, and the filter caps can retain a charge.
Normally, a separate filament and plate transformer are used with mercury or xenon rectifiers. There is a normal 30 to 60 sec delay for the filament to come up to normal temperature before the HT is applied. If you don't like mercury, use two 3B28 xenon rectifiers in a full wave CT circuit. If you don't care, two 816 or 866A work nicely. A 2.5 volt 10 amp transformer (at least 3 kv insulation) should be used for the 3B28 or 866A when working with HT supplies up to 1.5 kv or so.
You will get the blue glow with the mercury rectifiers (83, 816, or 866A). There is a glow in the 3B28 but it is enclosed in the heat shield and not seen from the outside.
As for breakage, a vented enclosure and a chassis bottom plate will protect tubes from breakage, animals, kids, etc. This should be done anyway since anode voltages can kill, and the filter caps can retain a charge.
wa2ise
Super Member
I've seen selenium listed as an ingredient in vitamin pills. So you probably got you minimum adult daily requirement that day...
And I've gotten my hands wet with PCBs from a Heathkit Cantenna ham radio dummy load. I'm still alive and kicking 40 years later...
nashvillebill
Super Member
Yep, I've got some 0A2 and 0B2 tubes around here I'd like to fire up just to have them glowing, but I don't want to spring for the $ for a PT just to run a glorified nightlight.
ab0ez
AB0EZ
Since all fluorescent light bulbs use mercury, even the "planet saver" CFL bulbs, I don't see where this is any big deal. It wasn't too long ago that every household had a mercury thermometer or three.
I say why not? Try it and let us all know how it works for you. I have some 866s and a few other types for 813 SE monoblock amps I will eventually build, when I get the time....ha ha....time? What's that?
Just make sure you use a built in automatic time delay so the mercury will be warmed up and vaporized. You can use a 6NO300 (300 second) or longer time delay "tube". It's a relay in a glass envelope that looks, well, like a tube.
http://www.vacuumtubes.net/Prices Relays, etc.htm
Disclaimer: I have no financial ties or affiliation with Vacuumtubes.net
Good luck with your project and keep us informed!
I say why not? Try it and let us all know how it works for you. I have some 866s and a few other types for 813 SE monoblock amps I will eventually build, when I get the time....ha ha....time? What's that?
Just make sure you use a built in automatic time delay so the mercury will be warmed up and vaporized. You can use a 6NO300 (300 second) or longer time delay "tube". It's a relay in a glass envelope that looks, well, like a tube.
http://www.vacuumtubes.net/Prices Relays, etc.htm
Disclaimer: I have no financial ties or affiliation with Vacuumtubes.net
Good luck with your project and keep us informed!
sheltie dave
Addicted Member
Mercury Vapor Rectifiers: Breakage in the Home
by Wally Chan
Mercury quantities and releases from household and industrial uses should be minimized because of the cumulative poison effects [1] [2] [3] [4] [5]. One uncommon specialized use is the mercury vapor rectifier, containing approximately 10ug of mercury vapor at 25 microns pressure (60 degrees C) and a total of .5 g of liquid elemental mercury [6]. If totally absorbed into the body, .5 g of elemental mercury has resulted in death, and approximately 1 to 4 gm is regarded as a lethal dose. But what risk occurs in practical circumstances from broken mercury vapor rectifiers?
In older homes, traces of mercury vapor are emitted from mold growth inhibiting paint additives [7], as well as from past thermometer and other spills. To control chronic exposure risk to continuously exposed householders, especially the young, an ATSDR recommended upper limit for mercury vapor in residences is 1.0 ug/m³; for elemental mercury [8]. This is a tighter limit than the OSHA occupational upper limit .1 mg/m³. The 10 ug of mercury vapor from a working rectifier, if suddenly released into a reasonable sized, multiple m³ volume room, will be well under these safety recommendation limits. However, there is still the question of evaporation of the remaining .5 g of liquid mercury into the room air. It turns out that vapor production is slow enough that chronic exposure over many years is the primary concern.
Consider first the case where the liquid mercury remains in one drop. The evaporation rate of a drop of liquid mercury was studied at room temperature in [9], both from an observed and theoretical standpoint. The undisturbed, long term rate of evaporation of a small drop of .2g appears to be of the order of 1 ug/hr. Measurements suggest that a protective film forms on exposed mercury drops and a loss rate of about .5 ug/hr exists for a 2 gm drop if undisturbed and 1.5 ug/hr for a .2 gm drop if frequently measured, disturbing the film. Theory predicted an order of magnitude faster evaporation and proportionality to surface exposed, so film formation and frequency of film disturbance is more significant than surface area alone. Also, the evaporation of a drop was found to violate the OSHA concentration limit by measurement [10] only within a 1 inch hemisphere surrounding the drop.
Evaporation rate data from [11] indicates that mercury evaporates approximately 10X faster at 60°C compared to room temperature (not including any film or atmospheric pressure effects). If the mercury rectifier envelope cracked but continued to remain warm for a long period of time, evaporation into the home environment could be faster than 1 ug/hr, but is unlikely to exceed 10 ug/hr.
Consider next a hypothetical10×10x8 ft=22.7 m³ room with mixing but no outside air exchange. The 1.0 ug/m³ limit will be reached in 23 hours from evaporation at room temperature, and perhaps an order of magnitude sooner (2 hrs) if the drop remains heated to 60°C. But if the room meets the rather minimal 4.7 L/s=16.9 m³/hr single occupant ventilation needs [12] the hot evaporation contribution cannot exceed (10 ug/hr)/(16.9 m³/hr)=.6 ug/m³. So if the room has enough air exchange and mixing for one or more person’s needs, the initial release plus subsequent hot evaporation cannot exceed the 1.0 ug/m³ vapor concentration chronic exposure limit and is more than two orders of magnitude below the OSHA occupational limit.
Consider now the case where the liquid mercury escapes the envelope, and gets into a form of increased surface area due to multiple droplet formation, adsorption onto carpet fibers or wood, or unfortunate vacuum cleaning. Since the evaporation rate attainable is proportional to the surface area, vapor concentration chronic exposure limits could be exceeded, as described in [13]. If liquid mercury gets soaked into carpet, textiles or wood fiber, or should it form an amalgam with aluminum, the substrate usually must be cut away and discarded as mercury hazardous waste.
Recommendations in the event of breakage:
If a mercury vapor rectifier tube’s envelope should break, turn off the associated equipment and allow it to cool down. Ventilate the room and leave until the equipment cools to room temperature. If there is a spill, follow the recommendations of [14] to clean up liquid mercury. Avoid actions that would break up drops or otherwise increase surface area and evaporation rate. Keep nose more than one inch from the spill at all times. Replace the tube and recycle the broken tube and spill kit as mercury hazardous waste. Enjoy your replacement rectifier’s operation, but also consider any additional measures you might take to avoid future releases.
References and Notes
1. Compact florescent lamps contain 4 mg Hg. Regular florescent lamps contain 40 mg Hg.
2. Breakage and spillage of certain household antiques (pendulum clocks, barometers) present opportunities for release of large amounts of liquid mercury. See for example http://jama.ama-assn.org/cgi/content/full/298/4/397.
3. Attempting to recover metals from heating amalgams in the home environment is a really bad idea. See http://www.cdc.gov/mmwr/preview/mmwrhtml/00014464.htm. Both the people and the house were unrecoverable. For those of you using mercury vapor rectifiers on aluminum chassis, Wikipedia has an interesting entry on amalgams relating to progressive aluminum destruction: http://en.wikipedia.org/wiki/Mercury-aluminum_amalgam.
4. The form of the mercury (elemental liquid metal, elemental vapor, compounds such as methyl mercury) matters regarding absorption and toxicity. For a discussion of health effects see http://cerhr.niehs.nih.gov/common/mercury.html.
5. Because of the extreme vulnerability of the nervous system in both developing fetus and children, pediatricians have recommended elimination of mercury from the home environment including minimizing direct use of mercury in doctor’s medical devices to lessen later environmental releases and the further contamination of the food chain. See http://aappolicy.aappublications.org/cgi/content/full/pediatrics;108/1/197 for discussion of mercury in vaccines, the environment, and effects on the developing nervous system. In addition to the direct exposure concerns, there is a global concern with mercury released in energy use, material goods, and in the waste flow of manufacturing. Even if the trace amounts are well below direct human harm, the concern is that the worldwide aggregate flow to the oceans feeds the methyl mercury chain and it ends up eventually at the top of the food chain, in us. For example, mercury is used in an electrolytic chlorine production process. The chlorine process leaks some mercury into the environment and the derived chlorine containing chemicals contain trace mercury. When these chemicals are used in household and industrial applications, trace mercury is released. Also, durable end products that contain chlorine (with trace mercury) as a component release the mercury contaminant originating from the chlorine production process as the discarded product degrades.
6. Electron Tube Division, Radio Corporation of America. Electron Tube Design, 1962 p805. Mercury content is .5 g total, .01 mg vapor for type 816.
7. Agocs, Etzel, Parrish, Paschal, Campagna, Cohen, Kilbourne, Hesse, “Mercury Exposure from Interior Latex Paint,” New England Journal of Medicine, Oct 18, 1990 p1096-1101.
8. Agency for Toxic Substances and Disease Registry (ATSDR) mercury vapor for residential indoor air not to exceed 1,000 ng/m³. See link cited in [13] below. OSHA, .1 mg/m³ maximum permitted mercury vapor exposure for 8 hr day, 40 hr week.
9. Thomas G. Winter. “The evaporation of a drop of mercury,” Am. J. Phys. 71(8), August 2003 p783-786.
10. Portable Jerome 431-X Mercury Vapor Analyzer instrument used in [9] to directly measure drops evaporating.
11. Dushman and Lafferty. Scientific Foundations of Vacuum Technique, 1962 p 697. Real evaporation will be slower due to film formation and atmospheric pressure. So 10X over room temperature is an upper limit estimate.
12. ASHRAE standard 62-1989 was used at its lowest limit: 10 cfm=4.7 L/s per occupant recommendation. This standard has since been upwardly upgraded. The American Society of Heating, Refrigerating and Air-Conditioning Engineering (ASHRAE) recommends (in its Standard 62-1999, “Ventilation for Acceptable Indoor Air Quality”) that homes receive .35 air changes per hour, but not less than 15 cubic feet per minute (cfm) per person. (From http://www.epa.gov/iaq/homes/hip-ventilation.html). The more conservative 10 cfm number was used for estimating toxicity, to reflect a more tightly shut household. For still more on this topic web search: house air exchange rate.
13. For an example of the household concentrations attainable from a single mercury switch spill from a thermostat see http://www.atsdr.cdc.gov/HAC/pha/watervliet/msa_p1.html. The ATSDR vapor threshold should not be exceeded by the evaporation of a single drop in the 60°C condition if there is normal room ventilation. But increasing the surface area even at room temperature can cause a potentially unsafe condition particularly for the young.
14. Cleanup procedure-see http://www.epa.gov/mercury/spills/index.htm#flourescent.
Posted: March 22, 2008 at 7:43 pm in Power Sources |
by Wally Chan
Mercury quantities and releases from household and industrial uses should be minimized because of the cumulative poison effects [1] [2] [3] [4] [5]. One uncommon specialized use is the mercury vapor rectifier, containing approximately 10ug of mercury vapor at 25 microns pressure (60 degrees C) and a total of .5 g of liquid elemental mercury [6]. If totally absorbed into the body, .5 g of elemental mercury has resulted in death, and approximately 1 to 4 gm is regarded as a lethal dose. But what risk occurs in practical circumstances from broken mercury vapor rectifiers?
In older homes, traces of mercury vapor are emitted from mold growth inhibiting paint additives [7], as well as from past thermometer and other spills. To control chronic exposure risk to continuously exposed householders, especially the young, an ATSDR recommended upper limit for mercury vapor in residences is 1.0 ug/m³; for elemental mercury [8]. This is a tighter limit than the OSHA occupational upper limit .1 mg/m³. The 10 ug of mercury vapor from a working rectifier, if suddenly released into a reasonable sized, multiple m³ volume room, will be well under these safety recommendation limits. However, there is still the question of evaporation of the remaining .5 g of liquid mercury into the room air. It turns out that vapor production is slow enough that chronic exposure over many years is the primary concern.
Consider first the case where the liquid mercury remains in one drop. The evaporation rate of a drop of liquid mercury was studied at room temperature in [9], both from an observed and theoretical standpoint. The undisturbed, long term rate of evaporation of a small drop of .2g appears to be of the order of 1 ug/hr. Measurements suggest that a protective film forms on exposed mercury drops and a loss rate of about .5 ug/hr exists for a 2 gm drop if undisturbed and 1.5 ug/hr for a .2 gm drop if frequently measured, disturbing the film. Theory predicted an order of magnitude faster evaporation and proportionality to surface exposed, so film formation and frequency of film disturbance is more significant than surface area alone. Also, the evaporation of a drop was found to violate the OSHA concentration limit by measurement [10] only within a 1 inch hemisphere surrounding the drop.
Evaporation rate data from [11] indicates that mercury evaporates approximately 10X faster at 60°C compared to room temperature (not including any film or atmospheric pressure effects). If the mercury rectifier envelope cracked but continued to remain warm for a long period of time, evaporation into the home environment could be faster than 1 ug/hr, but is unlikely to exceed 10 ug/hr.
Consider next a hypothetical10×10x8 ft=22.7 m³ room with mixing but no outside air exchange. The 1.0 ug/m³ limit will be reached in 23 hours from evaporation at room temperature, and perhaps an order of magnitude sooner (2 hrs) if the drop remains heated to 60°C. But if the room meets the rather minimal 4.7 L/s=16.9 m³/hr single occupant ventilation needs [12] the hot evaporation contribution cannot exceed (10 ug/hr)/(16.9 m³/hr)=.6 ug/m³. So if the room has enough air exchange and mixing for one or more person’s needs, the initial release plus subsequent hot evaporation cannot exceed the 1.0 ug/m³ vapor concentration chronic exposure limit and is more than two orders of magnitude below the OSHA occupational limit.
Consider now the case where the liquid mercury escapes the envelope, and gets into a form of increased surface area due to multiple droplet formation, adsorption onto carpet fibers or wood, or unfortunate vacuum cleaning. Since the evaporation rate attainable is proportional to the surface area, vapor concentration chronic exposure limits could be exceeded, as described in [13]. If liquid mercury gets soaked into carpet, textiles or wood fiber, or should it form an amalgam with aluminum, the substrate usually must be cut away and discarded as mercury hazardous waste.
Recommendations in the event of breakage:
If a mercury vapor rectifier tube’s envelope should break, turn off the associated equipment and allow it to cool down. Ventilate the room and leave until the equipment cools to room temperature. If there is a spill, follow the recommendations of [14] to clean up liquid mercury. Avoid actions that would break up drops or otherwise increase surface area and evaporation rate. Keep nose more than one inch from the spill at all times. Replace the tube and recycle the broken tube and spill kit as mercury hazardous waste. Enjoy your replacement rectifier’s operation, but also consider any additional measures you might take to avoid future releases.
References and Notes
1. Compact florescent lamps contain 4 mg Hg. Regular florescent lamps contain 40 mg Hg.
2. Breakage and spillage of certain household antiques (pendulum clocks, barometers) present opportunities for release of large amounts of liquid mercury. See for example http://jama.ama-assn.org/cgi/content/full/298/4/397.
3. Attempting to recover metals from heating amalgams in the home environment is a really bad idea. See http://www.cdc.gov/mmwr/preview/mmwrhtml/00014464.htm. Both the people and the house were unrecoverable. For those of you using mercury vapor rectifiers on aluminum chassis, Wikipedia has an interesting entry on amalgams relating to progressive aluminum destruction: http://en.wikipedia.org/wiki/Mercury-aluminum_amalgam.
4. The form of the mercury (elemental liquid metal, elemental vapor, compounds such as methyl mercury) matters regarding absorption and toxicity. For a discussion of health effects see http://cerhr.niehs.nih.gov/common/mercury.html.
5. Because of the extreme vulnerability of the nervous system in both developing fetus and children, pediatricians have recommended elimination of mercury from the home environment including minimizing direct use of mercury in doctor’s medical devices to lessen later environmental releases and the further contamination of the food chain. See http://aappolicy.aappublications.org/cgi/content/full/pediatrics;108/1/197 for discussion of mercury in vaccines, the environment, and effects on the developing nervous system. In addition to the direct exposure concerns, there is a global concern with mercury released in energy use, material goods, and in the waste flow of manufacturing. Even if the trace amounts are well below direct human harm, the concern is that the worldwide aggregate flow to the oceans feeds the methyl mercury chain and it ends up eventually at the top of the food chain, in us. For example, mercury is used in an electrolytic chlorine production process. The chlorine process leaks some mercury into the environment and the derived chlorine containing chemicals contain trace mercury. When these chemicals are used in household and industrial applications, trace mercury is released. Also, durable end products that contain chlorine (with trace mercury) as a component release the mercury contaminant originating from the chlorine production process as the discarded product degrades.
6. Electron Tube Division, Radio Corporation of America. Electron Tube Design, 1962 p805. Mercury content is .5 g total, .01 mg vapor for type 816.
7. Agocs, Etzel, Parrish, Paschal, Campagna, Cohen, Kilbourne, Hesse, “Mercury Exposure from Interior Latex Paint,” New England Journal of Medicine, Oct 18, 1990 p1096-1101.
8. Agency for Toxic Substances and Disease Registry (ATSDR) mercury vapor for residential indoor air not to exceed 1,000 ng/m³. See link cited in [13] below. OSHA, .1 mg/m³ maximum permitted mercury vapor exposure for 8 hr day, 40 hr week.
9. Thomas G. Winter. “The evaporation of a drop of mercury,” Am. J. Phys. 71(8), August 2003 p783-786.
10. Portable Jerome 431-X Mercury Vapor Analyzer instrument used in [9] to directly measure drops evaporating.
11. Dushman and Lafferty. Scientific Foundations of Vacuum Technique, 1962 p 697. Real evaporation will be slower due to film formation and atmospheric pressure. So 10X over room temperature is an upper limit estimate.
12. ASHRAE standard 62-1989 was used at its lowest limit: 10 cfm=4.7 L/s per occupant recommendation. This standard has since been upwardly upgraded. The American Society of Heating, Refrigerating and Air-Conditioning Engineering (ASHRAE) recommends (in its Standard 62-1999, “Ventilation for Acceptable Indoor Air Quality”) that homes receive .35 air changes per hour, but not less than 15 cubic feet per minute (cfm) per person. (From http://www.epa.gov/iaq/homes/hip-ventilation.html). The more conservative 10 cfm number was used for estimating toxicity, to reflect a more tightly shut household. For still more on this topic web search: house air exchange rate.
13. For an example of the household concentrations attainable from a single mercury switch spill from a thermostat see http://www.atsdr.cdc.gov/HAC/pha/watervliet/msa_p1.html. The ATSDR vapor threshold should not be exceeded by the evaporation of a single drop in the 60°C condition if there is normal room ventilation. But increasing the surface area even at room temperature can cause a potentially unsafe condition particularly for the young.
14. Cleanup procedure-see http://www.epa.gov/mercury/spills/index.htm#flourescent.
Posted: March 22, 2008 at 7:43 pm in Power Sources |
Wow!
Thank you Sir! Nice to have a specific reference. This is obviously a very polarizing topic.
I did have a chance to work up a draft choke input PS, using a UTC S-39 PT and a S-32 swinging choke I recently picked up in trade. 8 uV of B+ ripple should hopefully be clean enough for this build, despite any additional noise the 83 might inject into the system. This will be my first choke input design.
Look OK?
Comments?
Suggestions?
Thank you Sir! Nice to have a specific reference. This is obviously a very polarizing topic.
I did have a chance to work up a draft choke input PS, using a UTC S-39 PT and a S-32 swinging choke I recently picked up in trade. 8 uV of B+ ripple should hopefully be clean enough for this build, despite any additional noise the 83 might inject into the system. This will be my first choke input design.
Look OK?
Comments?
Suggestions?
nasadowsk
Bow:good, hunt:needs work
Didn't the 0Z4 have mercury in it, too? IIRC, one disadvantage is that mercury rects create a bit of extra 'hash' noise.
Interesting technology - it scaled up to VERY high voltage and currents - ASEA's HVDC systems were originally mercury arc (ignitron*), and they were used in commuter trains in the northeastern US, both onboard (New Haven RR, PRR, etc), and wayside (Lacawanna, LIRR, NYC subway), where currents could reach 5 figures.
*There's a cut away of one on display at the Deutches Museum in Munich.
Interesting technology - it scaled up to VERY high voltage and currents - ASEA's HVDC systems were originally mercury arc (ignitron*), and they were used in commuter trains in the northeastern US, both onboard (New Haven RR, PRR, etc), and wayside (Lacawanna, LIRR, NYC subway), where currents could reach 5 figures.
*There's a cut away of one on display at the Deutches Museum in Munich.
Gary Kaufman
Well-Known Member
I've built amps with both 83's and 866jr's. Don't underestimate the hassles involved.
They need to be pre-heated before B+ is applied, conditioned if they've been shipped on their sides, don't like cold rooms, need to be choke loaded etc. Choke inputs require "real" chokes that were designed for choke input usage or they will buzz - and a minimum load at all times. Vintage swing/smooth chokes with oil caps work best. Even with a choke input I found it was best to "slow start" the 866jr's and use a damper diode for that. They also may need RF chokes on the filament.
I went thru a LOT of fuses getting it right on my 211 amp.
The ham guys figured out that Xe rectifiers worked better long ago. Damper diodes work just as well with a lot less hassle and cost.
But they do look nice!
- Gary
The UTC S-32 swinging choke I've planned on using as the choke input is a 4/20 Hy with 100 Ohms DCR, current capacity of 225 mA, and tested up to 2700 V. Hopefully it fits the bill. The S-39 PT is a 490-400-0-400-490 at 175 mA with 5V/3A, 2.5VCT/6A and 6.3VCT/4A. I don't remember what the DCR of the OPTs is, but if 5V drop is typical, my wall AC typically floats around 123VAC, so I should be right at 300V B+ for the 45s, and 255-260V for the driver tubes, which most likely would be 6DJ8s....