IMPROVEMENTS IN CONVEYING HEAT AND POWER TO A DISTANCE, AND IN APPARATUS FOR THAT PURPOSE
Year: 1881

page_text: "
LETTERS PATENT to William Thomas Whiteman, of No. 7, Staple Inn, in the
County of Middlesex, Patent Agent, for an Invention of IMPROVEMENTS IN
CONVEYING HEAT AND POWER TO A DISTANCE, AND IN APPARATUS FOR
THAT PURPOSE." A communication from abroad by John Newton, of the City
of New York, in the United States of America, General of Engineer Corps,
United States Army.
PROVISIONAL SPECIFICATION left by the said William Thomas Whitemań
at the Office of the Commissioners of Patents on the 10th May 1881.
WILLIAM THOMAS WHITEMAN, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN CONVEYING HEAT AND POWER TO A DISTANCE,
AND IN APPARATUS FOR THAT PURPOSE." [A communication from abroad by
John Newton, of the City of New York, in the United States of America, General
of Engineer Corps, United States Army.]
This Invention has for its object to supply heat and power from a central
source to public and other buildings by generating and distributing through mains
and pipes a suitable agent, and conveying it to interior apparatus in said buildings,
such as engines, radiators, ranges, and the like, for producing motive power and
heat for warming, cooking, drying, or other purposes.
Careful consideration of methods already in use or recommended for use to
furnish power and heat in this way to buildings at distances from the generators
will clearly exhibit their incompleteness and insufficiency for the objects proposed
to be accomplished, as well as considerable waste of heat in their application.
One method in use consists in conducting saturated steam fresh from the boilers
without additional preparation through pipes or mains to the places to be supplied
with power and heat.
In steam thus generated in boilers over water the relation between the tem-
perature pressure and density is fixed so that the same density and pressure
always correspond to the same temperature, and such steam known as saturated
steam is both at the condensing and at the generating point, condensation taking
Dun CJ1

page_text: place if the temperature be allowed to fall, and more water being evaporated and
more steam generated if the temperature be raised.
Steam of a higher temperature is necessary for some of the purposes named than
for others. For warming buildings any temperature which will heat the air of the
space to 70° Fahrenheit and maintain that degree of heat will suffice, so that
steam from 212° upwards is capable of producing the desired effect. For the
purposes of power the pressure of the steam may vary as a general rule from
seventy pounds on the square inch to about one hundred pounds, and the steam
must therefore have a corresponding temperature of, say, 303° to 350° or
thereabout.
For the purposes of cooking in all the varieties in common use, and to perform these
to perfection and with despatch, a range of temperature from that of boiling water
to a degree as high as between 400° and 450° Fahrenheit is required. For purposes
of illustration let a temperature of 430° be assumed as sufficient for all the varieties
of cooking in common use. Saturated steam at this temperature has a pressure of
about three hundred and fifty pounds on the square inch, and it is not to be
supposed when the risk of life and property from such enormous pressure is con-
sidered that a system involving boilers to generate such steam, mains to conduct it
in the large quantities necessary for the supply of populous neighbourhoods, and
interior apparatus in houses, ranges, radiators, air heaters, and the like, to withstand
it would be tolerated by the public authorities or even considered to be practicable
or desirable by the proprietors themselves.
Steam of pressures equal to or even exceeding the high pressure aforesaid may
have been used for power, but only in small quantities, and with special precautions
as to the strength of the materials of the boilers and apparatus not applicable to a
system for supplying steam in the large quantities required to furnish heat for
cooking in populous neighbourhoods. Saturated steam therefore, considering it
merely as a source of heat and power, and omitting for the present reférence to
other grave defects, may be used to furnish motive power and heat for warming
buildings and for limited varieties of cooking, but other varieties of cooking in
common use either could not be performed, or not without considerable delay and
imperfection, if only safe and moderate pressures be tolerated. On the other hand a
pressure of the steam corresponding with a temperature proper for cooking is
coupled with an imminent danger to person and property, and with great additional
cost, arising from the unusual strength necessary for the generators and the whole
apparatus, including the mains and interior apparatus in the houses. A very serious
defect of another kind attaches to the use of saturated steam. However well
guarded the whole apparatus, including the mains, may be against loss of heat from
radiation, induction, and other causes, a fall of temperature begins as soon as the
steam leaves the boilers, and continues at a progressive rate to the end of the mains.
Condensation throughout the whole distance traversed by the steam ensues, and
causes the deposition of water in the mains and pipes, and especially in depressions.
The presence of water so formed increases the rate of condensation, and the steam
passing over the water of condensation is furnished to the consumers wet and with
a lowered temperature and pressure. Contrivances have to be used to free the
mains and other parts from water, but these will not effect the delivery of the steam
dry and unimpaired in temperature and pressure, because from the nature of
saturated steam condensation throughout the system and the deposition of water
must continue.
The mains must be freed from water lest they should be choked at the depressions,
although this operation will not restore the quality of the steam, and steam of
higher pressure than is needed for power must be generated in the boilers to com-
pensate for loss of pressure, and after all the cost and trouble of these operations
the steam will be furnished to the consumers in an impaired condition for 'heating,
cooking, and especially for power.
The operators of the scheme of supplying saturated steam, even if they should
assume the extraordinary risk of generating and conveying to distances steam for

page_text: cooking purposes at a temperature of 430° and pressure of about three hundred
and fifty pounds, would necessarily use boilers and mains other than those employed
for stean of lower. temperature and pressure, and applied merely to purposes of
power and warmth, unless they should recklessly incur additional risk by multi-
plying the quantity of steam of the highest pressure and applying it to supplying
power and warmth as well as to cooking purposes. Two sets of mains and other
apparatus would therefore be necessary in this system, one for steam of high
pressure, the other for steain of low pressure.
A second mode of supplying power and heat at distances from the generating
point, as stated by its projectors, is by means of water heated in boilers under
pressure and conveyed thence in mains. The use of water at high temperature
and corresponding pressure for furnishing heat for cooking would involve risks
even more serious than those enumerated for saturated steam of the same tempera-
ture and pressure because any sudden relaxation of pressure which might arise
from accident to the apparatus in any part, or from carelessness in manipulation,
would permit a portion of the water to develop with a bound into steam, and
this would act like an explosive compound, giving off explosions in such rapid
succession as to constitute one long continuous explosion spreading over a con-
siderable length of the mains and other apparatus, and therefore more destructive
than the bursting produced by the overstrain of a constant pressure from steam.
Hot water when applied to purposes of power is first converted into steam by
simply relieving the pressure. A small portion only is developed into steam of
adequate pressure, leaving large surplus to be sent back to the generators to be
reheated. Considering the applications of hot water to the three purposes of
power, cooking, and warming, and comparing it pound for pound with steam of the
same temperature and pressure, it will be found that one pound of steam will
perform the average functions of about four pounds of water, so that in the case of
water a large excess of transportation must be provided involving additional
consumption of fuel.
It is therefore evident that heated water for the purposes named would be more
dangerous and less economical than steam..
In the present Invention these difficulties are overcome by using, instead of
saturated steam taken directly from the boilers, or water heated in boilers under
pressure, superheated steam of comparatively low pressure and high temperature.
The steam generated in the boilers is first superheated, so as to have the desired
temperature and pressure, and then carried in the underground mains and pipes to
the required distances from the generators to be supplied to the interior apparatus
in condition suitable for working engines and other machinery, and for supplying
heat of the degrees needed for cooking with perfection and despatch, for warming
buildings, and for other purposes.
The steam is generated at a pressure of one hundred pounds, and a temperature
of about 328° Fahrenheit, or other moderate pressure and corresponding temperature,
and superheated without material increase of pressure to between 400° and 450°
Fahrenheit or thereabout. The steam is allowed to expand during the superheating
operation, and the pressure does not increase with the temperature, or at least not
in the same degree. The temperature should not be so high that the steam when
supplied to the engines will injuriously affect the pistons and other parts with
which it comes in contact. The degree of temperature may be varied from that
mentioned, as may be judged expedient for the locality and under the circumstances
of the case.
It is generally preferred to superheat the steam without change in pressure, but
this is not essential. The steam if desired can in superheating be raised also in
pressure, and allowed to expand into the mains, or the pressure can be reduced in
the superheating chamber, and in either case steam of the required low pressure
and high temperature be obtained.
In the improved system no condensation can take place in the apparatus or in
the mains until-by radiation and conduction of heat away from the steam the

page_text: temperature has been reduced to the temperature. of saturation, or about that of
the steam in the boilers, and whenever, owing to the length of line or other
circumstances, the steam is liable to fall below the proper degree it is reheated by
passing through auxiliary superheaters placed at determinate points along the
route of the distributing mains. These auxiliary superheaters are not interpolated
with the object of restoring the steam in the mains to the superheated state, for the
steam is never to be allowed to fall out of that condition, but only to restore heat
sufficient to keep the steam highly efficient, especially in respect to its cooking
qualities.
It may sometimes be inexpedient, especially when the course of the main is long,
to superheat the steam at the start to such an extent as to retain heat throughout
the course sufficient for cooking, because the temperature in the beginning might
thereby be made inconvenient for domestic purposes and injurious to engines.
This objection is avoided by the use of the superheaters along the route, but these
will not ordinarily be necessary.
As the steam in this system after leaving the boilers is always kept in a super-
heated state there will be no condensation in the mains and supplying apparatus,
and the system will in operation be relieved of the cost and injurious consequences
contingent upon condensation in the mains which necessarily attends the use of
saturated steam for the purposes named.
As the steam superheated as explained will suffice perfectly for all the purposes
of power, cooking, and warmth, one set only of boilers, mains, and apparatus will
be necessary.
The weight of metal in the boilers, mains, and other apparatus may be much less
than that required in the same parts to sustain the pressure due to saturated steam
or heated water at the temperature proper for the various kinds of cooking.
The pressure of the steam from the generators and superheaters will generally
be sufficient to keep up a free circulation from the boilers through the superheaters,
mains, and distributing pipes and apparatus in the buildings to be supplied, and
also through any additional superheaters that may be placed along the route, but
if desired forcing pumps can be employed at various points for the purpose of
assisting the circulation..
After passing through the apparatus in the buildings supplied, whether these be
radiators, ranges, or engines, one or all, the steam can be allowed to escape into the
atmosphere, but it is preferred to return it to the generators by suitable return
pipes. Force or suction pumps, or both, or other appropriate apparatus can be
employed to ensure the circulation through the return pipes.
As a greater supply of steam will be required during one season than another,
and at certain hours of the day than at others, the velocities impressed upon the
steam would be different at different times during the passage through the super-
heaters, and consequently the periods of time during which the steam would be
subjected to heat in the superheaters would accordingly be longer or shorter. To
compensate for this difference, and to ensure such degree of superheating at any
time as may be necessary, regulating and controlling devices are employed, so that
when the steam passes slowly through the superheater the length and surface of
the superheated portion can be diminished, and when the steam passes through the
superheater more quickly the length and area of the superheated portion can be
increased.-
The superheating of the steam can be effected by means of the products of
combustion from the boiler furnaces, and the temperature and pressure of the
superheated steam can be regulated by suitable cocks and dampers in the steam
pipes and flues respectively.
In the transportation of the steam loss of heat from radiation, conduction, and
other causes, will take place from the time it leaves the superheaters to its delivery
at the points where it is to be used, and to provide as far as possible against such
loss, the mains and other necessary parts are jacketed with some non-conductor or
imperfect conductor of heat adapted to withstand high temperature, such as have

page_text: beretofore been used for jacketing stove pipes, and enclosed in a box or wrapper
rendered water tight, or nearly so, by some of the well known substances suitable
for such purpose, so that the mains or pipes shall be surrounded by the confined
air. Or the space about the mains can be filled with a packing of non-conducting
or imperfectly conducting material.
A box of wood, concrete, brick, or other imperfect conductor plastered inside and
out could be used.
Transverse partitions are employed to support the mains or pipes in their boxes,
and to prevent circulation within the latter. A small pipe with automatic valve is
connected with the interior of the box to let off air and vapour, and prevent
injurious pressure upon the box.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Thomas Whiteman in the Great Seal Patent Office on
the 9th November 1881.
WILLIAM THOMAS WHITEMAN, of No. 7, Staple Inn, in the County of Middlesex,
Patent Agent. "IMPROVEMENTS IN CONVEYING HEAT AND POWER TO A DISTANCE,
AND IN APPARATUS FOR THAT PURPOSE." A communication from abroad by
John Newton, of the City of New York, in the United States of America, General
of Engineer Corps, United States Army.
This Invention has for its object to supply heat and power from a central source
to public and other buildings, by generating and distributing through mains and
pipes a suitable agent, and conveying it to interior apparatus in said buildings,
such as engines, radiators, ranges, and the like for producing motive power and
heat for warming, cooking, drying, or other purposes.
Careful consideration of methods already in use or recommended for use to
furnish power and heat in this way to buildings at distances from the generators,
will clearly exhibit their incompleteness and insufficiency for the objects proposed
to be accomplished, as well as considerable waste of heat in their application.
One method in use consists in conducting saturated steam fresh from the boilers,
without additional preparation through pipes or mains, to the places to be supplied
with power and heat. In steam thus generated in boilers over water, the relation
between the temperature pressure and density is fixed so that the same density
and pressure always correspond to the same temperature, and such steam, known as
saturated steam, is both at the condensing and at the generating point, condensation
taking place if the temperature be allowed to fall, and more water being evaporated
and more steam generated if the temperature be raised.
Steam of a higher temperature is necessary for some of the purposes named than
for others. For warming buildings, any temperature which will heat the air of the
space to 70° Fahrenheit, and maintain that degree of heat, will suffice, so that
steam from 212° upwards is capable of producing the desired effect. For the
purposes of power the pressure of the steam may vary as a general rule from
seventy pounds on the square inch to about one hundred pounds, and the steam
must therefore have a corresponding temperature of, say, 303° to 380°, or there-
about.
For the purposes of cooking in all the varieties in common use, and to perform
these to perfection and with despatch, a range of temperatures from that of boiling
water to a degree as high as between 400° and 450° Fahrenheit is required. For
purposes of illustration, let a temperature of 430° be assumed as sufficient for all
the varieties of cooking in common use. Saturated steam at this temperature has
a pressure of about three hundred and fifty pounds on the square inch, and it is
not to be supposed when the risk of life and property from such enormous pressure
is considered, that a system' involving boilers to generate such steam, mains to
conduct it in the large quantities necessary for the supply of populous neighbour-
hoods and interior apparatus in houses, ranges, radiators, air heaters, and the like
to withstand it, would be tolerated by the public authorities, or even considered
to be practicable and desirable by the proprietors themselves.
Steam of pressure equal to or even exceeding the high pressure aforesaid may
have been used for power, but only in small quantities, and with special precautions
as to the strength of the materials of the boilers and apparatus not applicable to a
system for supplying steam in the large quantities required to furnish heat for
cooking in populous neighbourhoods.

page_text: Saturated steam therefore, considering it merely as a source of heat and power,
and omitting for the present reference to other grave defects, may be used to
furnish motive power and heat for warming buildings, and for limited varieties of
cooking; but other varieties of cooking in cominon use either could not be
performed, or not without considerable delay and imperfection, if only safe and
moderate pressures be tolerated. On the other hand a pressure of the steam
corresponding with a temperature proper for cooking is coupled with an imminent.
danger to person and property, and with great additional cost arising from the
unusual strength necessary for the generators, and the whole apparatus, including
the mains and interior apparatus in the houses. A very serious defect of another
kind attaches to the use of saturated steam. However well guarded the whole
apparatus, including the mains, may be against loss of heat from radiation, induction,
and other causes, a fall of temperature begins as soon as the steam leaves the
boilers, and continues at a progressive rate to the end of the mains. Condensation
throughout the whole distance traversed by the steam ensues, and causes the
deposition of water in the mains and pipes, and especially in depressions. The
presence of water so formed increases the rate of condensation, and the steam
passing over the water of condensation is furnished to the consumers wet, and with
a lowered temperature and pressure. Contrivances have to be used to free the
mains and other parts from water, but these will not effect the delivery of the
steam dry and unimpaired in temperature and pressure, because from the nature of
saturated steam, condensation throughout the system and the deposition of water
must be continual.
The mains must be freed from water lest they should be choked at the depressions,
although this operation will not restore the quality of the steam and steam of
higher pressure than is needed, for power must be generated in the boilers to
compensate for loss of pressure, and after all the cost and trouble of these operations
the steam will be furnished to the consumers in an impaired condition for heating,
cooking, and especially for power.
The operators of the scheme of supplying saturated steam, even if they should
assume the extraordinary risk of generating and conveying to distances steam for
cooking purposes at a temperature of 430°, and pressure of about three hundred
and fifty pounds, would necessarily use boilers and mains other than those
employed for steam of lower temperature and pressure, and applied merely to
purposes of power and warmth, unless they should recklessly incur additional risk
by multiplying the quantity of steam of the highest pressure, and applying it to
supplying power and warmth as well as to cooking purposes. Two sets of mains
and other apparatus would therefore be necessary in this system, one for steam of
high pressure, the other for steam of low pressure.
A second mode of supplying power and heat at distances from the generating
point as stated by its projectors, is by means of water heated in boilers under
pressure, and conveyed thence in mains. The use of water at high temperature
and corresponding pressure for furnishing heat for cooking would involve risks
even more serious than those enumerated -for saturated steam of the same tem-
perature and pressure, because any sudden relaxation of pressure which might
arise from accident to the apparatus in any part, or from carelessness in manipu-
lation, would permit a portion of the water to develop with a bound into steam,
and this would act like an explosive compound, giving off explosions in such rapid
succession as to constitute one long continuous explosion spreading over a
considerable length of the mains and other apparatus, and therefore inore destructive
than the bursting produced by the overstrain of a constant pressure from steam.
Hot water when applied to purposes of power is first converted into steam by
simply relieving the pressure. A small portion only is developed into steam of
adequate pressure, leaving a large surplus to be sent back to the generators to be
reheated. Considering the applications of hot water to the three purposes of
power, cooking, and warming, and comparing it pound 'for pound with steam of, the
same temperature and pressure, it will be found that one pound of steam will

page_text: perform the average function of about four pounds of water, so that in the case of
water a large excess of transportation must be provided, involving additional
consumption of fuel.
It is therefore evident that heated water for the purposes named would be more
dangerous and less economical than steam.
In the present Invention these difficulties are overcome by using, instead of
saturated steam taken directly from the boilers, or water heated in boilers under
pressure, superheated steam of comparatively low pressure and high temperature.
The steam generated in the boilers is first superheated so as to have the desired
temperature and pressure, and then carried in the underground mains and pipes to
the required distances from the generators to be supplied to the interior apparatus,
in condition suitable for working engines and other machinery, and for supplying
heat of the degrees needed for cooking with perfection, and despatch for warming
buildings and for other purposes.
The steam is generated at a pressure of one hundred pounds, and a temperature
of about 328° Fahrenheit or other moderate pressure and corresponding teni-
perature, and superheated without material increase of pressure to between 400°
and 450° Fahrenheit, or thereabout. The steam is allowed to expand during the
superheating operation, and the pressure does not increase with the temperature,
or at least not in the same degree. The temperature should not be so high that
the steam when supplied to the engines will injuriously affect the pistons and other
parts with which it comes in contact. The degree of temperature may be varied
from that mentioned, as may be judged expedient for the locality and under the
circumstances of the case.
It is generally preferred to superheat the steam without change in pressure, but
this is not essential. The steam, if desired, can in superheating be raised also in
pressure and allowed to expand into the mains, or the pressure can be reduced in
the superheating chamber, and in either case steam of the required low pressure
and high temperature be obtained.
In the improved system no condensation can take place in the apparatus or in
the mains, until by radiation and conduction of heat away from the steam the
temperature has been reduced to the temperature of saturation, or about that of the
steam in the boilers, and whenever, owing to the length of line or other cir-
cumstances, the steam is liable to fall below the proper degree, it is reheated by
passing through auxiliary superheaters, placed at determinate points along the
route of the distributing mains. These auxiliary superheaters are not interpolated
with the object of restoring the steain in the mains to the superheated state, for
the steam is never to be allowed to fall out of that condition, but only to restore
heat sufficient to keep the steam highly efficient, especially in respect to its cooking
qualities.
It may sometimes be inexpedient, especially when the course of the main is long,
to superbeat the steam at the start to such extent as to retain heat throughout,
the course sufficient for cooking, because the temperature in the beginning might
thereby be made inconvenient for domestic purposes and injurious to engines. This
objection is avoided by the use of the superheaters along the route, but these
will not ordinarily be necessary.
As the steam in this system after leaving the boilers is always kept in a super-
heated state, there will be no condensation in the mains and supplying apparatus,
and the system will in operation-be-relieved of the cost and injurious consequences
contingent upon condensation in the mains, which necessarily attends the use of
saturated steam for the purposes named.
As the steam superheated, as explained, will suffice perfectly for all the purposes
of power cooking and warmth, one set only of boilers, mains, and apparatus will
be necessary.
The weight of metal in the boilers, mains, and other apparatus may be much
less than that required in the same parts to sustain the pressures due to saturated
steam or heated water as the temperature proper for the various kinds of cooking.

page_text: The pressure of the steam from the generators and superheaters will generally.
be sufficient to keep up a free circulation from the boilers through the superheaters,
mains, and distributing pipes and apparatus in the buildings to be supplied, and
also through any additional superheaters that may be placed along the route; but
if desired forcing pumps can be employed at various points for the purpose of
assisting the circulation.
After passing through the apparatus in the buildings supplied, whether these be
radiators, ranges, or engines, one or all, the steam can be allowed to escape into
the atmosphere, but it is preferred to return it to the generators by suitable return
pipes. It will return partly perhaps as steam and partly as water of condensation.
Force or suction pumps, or both, or other appropriate apparatus can be employed
to ensure the circulation through the return pipes.
As a greater supply of steam will be required during one season than another,
and at certain hours of the day than at others, the velocities impressed upon the
steam would be different at different times during its passage through the super-
heaters, and consequently the periods of time during which the steam would be
subjected to heat in the superheaters would accordingly be longer or shorter. To
compensate for this difference, and to ensure such degree of superheating at any
time as may be necessary, regulating and controlling devices are employed, so that
when the steam passes slowly through the superheater the length and surface of
the superheated portion can be diminished, and when the steam passes through the
superheater more quickly the length and area of the superheated portion can be
increased.
The superheating of the steam can be effected by means of the products of
combustion from the boiler furnaces, and the temperature and pressure of the super-
heated steam, can be regulated by suitable cocks and dampers in the steam pipes
and flues respectively.
In the transportation of the steam, loss of heat from radiation, conduction and
other causes will take place from the time it leaves the superheaters to its delivery
at the points where it is to be used; and to provide as far as possible against such
loss, the mains and other necessary parts are jacketed with some non-conductor or
imperfect conductor of heat adapted to withstand high temperature, such as have
heretofore been used for jacketing stove pipes, and enclosed in a box or wrapper
rendered water tight or nearly so by some of the well known substances suitable
for such purpose, so that the mains or pipes shall be surrounded by the confined
air. Or the space about the mains can be filled with a packing of non-conducting
or imperfectly conducting material.
A box of wood, concrete, brick, or other imperfect conductor, plastered inside and
out, could be used.
Transverse partitions are employed to support the mains or pipes in their boxes,
and to prevent circulation within the latter.
A small pipe with automatic valve is connected with the interior of the box to
let off air and vapour, and prevent injurious pressure upon the box.
Having thus described the nature of the said Invention as communicated to
me by my foreign correspondent, and the manner in which it is to be performed, I
wish it to be understood that I do not limit myself to the precise details described,
as they may be varied without departing from the nature of the said Invention,
but I claim,
•
First. The method of supplying heat and power from a central source to public
and other buildings by generating and distributing through mains and pipes super-
heated steam of high temperature and relatively low pressure, and conveying said
steam into said buildings to suitable interior apparatus for producing motive power,
and for warming, cooking, drying, or other purpose, substantially as described,
whereby excess of pressure in the mains and pipes and connected apparatus is
avoided, and the steam is prevented from condensing, and can be supplied to the
said interior apparatus under conditions suitable for the desired purpose as set
forth.

page_text: Secondly.. An organized system for supplying heat and power from a central
source by means of superheated steam of low pressure and high temperature,
comprising boilers for generating steam, and superheaters for raising the tempera-
ture of the steam while permitting it to expand, in combination with underground
distributing mains and pipes, and the interior apparatus for producing motive
power and heat for various purposes, as ranges, radiators, and engines, as set forth.
Thirdly. The combination with underground distributing mains and pipes of
steam generators, superheaters for raising the temperature of said steam after it
leaves the generators, and means as indicated for regulating the temperature and
pressure of the superheated steam, and controlling the supply to said mains and
pipes, substantially as described.
Fourthly. The combination with distributing mains and pipes of steam
generators and superheaters for supplying steam of low pressure and high
temperature to said mains and pipes, of auxiliary heaters located at suitable points
along the route of said mains or pipes for maintaining the temperature of the
stean, substantially as described.
Fifthly. The combination with distributing mains and pipes of one or more
boilers and furnaces, one or more superheaters connected with said boilers, flues
connected with the fire chambers of said furnaces, and arranged to carry the
products of combustion over said superheaters and dampers for cutting off or
admitting the said products of combustion more or less as required, substantially as
described.
-
Sixthly. A main for distributing steam enclosed in a water tight box, and
surrounded by confined air or embedded in non-conducting material, substantially
as described.
Seventhly. The combination of a distributing main, a tight box enclosing the
same, and transverse partitions supporting the main, and preventing circulation
within the box, substantially as described.
Eighthly. The combination with a distributing main or pipe for conveying a hot
fluid and box enclosing said main or pipe of outlets for relieving pressure within
the box, substantially as described.
Ninthly. The combination with underground distributing mains and pipes, and
boilers and superheaters for supplying superheated steam of low pressure and high
temperature to said mains and pipes to be conveyed to interior apparatus for
utilizing the steam of return pipes for returning the steam or water of condensation
so that it can be raised, substantially as described.
In witness whereof, I, the said William Thomas Whiteman, have hereunto set
my hand and seal, this Eighth day of November, in the year of our Lord
One thousand eight hundred and eighty-one.
W. T. WHITEMAN. (L.S.)