Document ZnwDxXYVRnLbaXYLx35qBKqdV
Jas. P. Marsh & Company
Specialties, Healing
MARSH SYSTEM UNITS
MARSH EQUALIZER AND BOILER RETURN TRAP
The Marsh System Unit
the return lines, it causes
No. 10 Equalizer and Boil
the float to rise until a pre
er Return Trap is the most important automatic ele
determined point has been reached.
ment entering into the
At this point, the float
construction of a Marsh
will have risen to such an
Vapor System of Heating.
extent so as to cause the
The entire successful oper
mechanism within the trap
ation of the system de
to open an inlet port con-
pends upon the functions
nected directly to the
of this Marsh System Unit
boiler by means of piping
of assuring perfect circula
to the boiler header. This
tion throughout the entire
action of the return trap
heating system and return
permits the steam pressure
of water to the boiler. .
from within the boiler to
Equalizer Operation
pass on through the piping into the trap,thus equalizingthedifferencein pressure between
Incorporated in the head construction of the trap and boiler, and as the pressures are
the unit is an integral ball check between now the same, the water has sufficient force
the steam supply and return connections due to its height above the level of the water
as shown on the drawing. With this ar line to gravitate into the boiler--the source
rangement, should the depth of vacuum in . from which it started in the form of steam.
the supply system become greater than within the return system, ,the integral ball
Construction
check will open permitting equalization of ' The body is of heavy cast iron fitted with a
the vacuum in the supply and return companion flange which bolts on the inlet
systems.
opening. The head is so designed that when
Return of Water to Boiler
it is removed from .the body, the entire mechanism can be taken out in one opera
Water in the return system seeking its own tion. The cast brass float and connecting
level will find its way into the body of the rods are pivoted with stainless steel pins to
trap, and as it continues to accumulate in resist rusting or w,earing action.
No. 11 AIR VENT TRAP
This trap is
designed to
providea pos
itive meansof expelling air
at the termi
nus of the re turn system
in the boiler'
room and at
the same time prevent leakage. A float mechanism within the trap allows
the air to pass from the top of the return : line into this trap, and to escape through
the air outlet at the top of the trap by means of piping, which extends above the normal water level of the return system.
The ball check valve prevents the air from re-entering the system at this point. As water builds up in this trap, the float rises, closing the air outlet and retaining the water in the return system.
This trap has sufficient air expelling ca pacity to take care of all size jobs up to
10,000 square feet direct radiation. On larger installations where more than one Marsh System Unit No. 10 Equalizer and Boiler Return Trap are used, one No. 11 Air Trap is installed for each.
The body is of pressed steel with a cast iron cover. The float mechanism is made of non-corrosive metals and the air outlet fitted with a ball check arrangement. The Trap is made in one inch size only.
MARSH No. 5 VENT
On vapor systems this vent is the air ex pelling unit at the ends of steam mains. It expels air until steam has reached
the thermostatic element. When steam reaches this ele ment, it expands upwardly, closing the outlet port pre venting vapor from escaping.
This vent is fitted with a float to eliminate the possi bilities of water surging and also a vacuum top feature 10 prevent air from re-entering
the system.
848
(s.-P. Marsh & Company
Specialties, Heating
MARSH SYSTEM UNITS
MARSH No. 7 AIR ELIMINATOR
-if'-The Marsh No. 7 Air Eliminator is ^another form of air expelling unit
' i.iiiised fr the 53016 purpose as the .Marsh Air Vent Trap, illustrated
--V'r'and described on page 848. It may
-^"'be substituted with safety where so :'"' desired. It is a large free vent for the v -i'airatall temperatures, cannot waterv fog, does not spit or leak water.
- - -phe Marsh No. 7 Air Eliminator is"equipped with a cylindrical float '/K 'arrangement to prevent water from
'' 'im-eing, and a thermostatic element
as an additional protection against leakage of vapor steam should it reach this point.
The air port allows free expulsion of air, and has a vacuum top feature to prevent air from re-entering the system. This eliminates the need for
a check valve on the air outlet.
Made in % inch and 1 inch connec
tions and adjusted at factory to op erate automatically from below pres sure on up to 10 pounds steam pressure.
V;. MARSH No 8 DRIP TRAP
~ k This trap is continuous in dis-
t ''.charge and is designed to
' quickly remove condensation
; : and air from drip points on steam mains, steam risers, steam
coils, or blast heaters, or for any / t.like service within the capacity
Sp of the trap. The design permits a deep water seal on the discharge
valve. This water discharge valve is float controlled and lo cated at a low point in the bot tom of the trap and air is re moved through a thermostati
cally controlled port in the cap of the trap. The thermostatic member used is our standard assembly as in the No. 1 Marsh Radiator Trap. Normally air is discharged through a port di rectly to the outlet connections of the trap. In cases where the trap may be required to dis
charge to a wet return the air discharge may be connected to a dry return from a special open-
CAPACITIES
Steam Pressure Capacities in lb. water per hr.
500 1 900 2 1400 3 1600 4 1800 5 2000 10 3200 15 4000
ing tapped in the cap of the trap. Body of trap is provided with
one 134-inch tapped inlet and two 134-inch tapped outlet openings. These openings are located so as to permit direct connection both to inlet arid from outlet..
The trap may be suspended directly in the piping and no other supports are necessary: The thermostatic element screws directly in the cap of the trap and is interchangeable with the element from the No. 1 Radiator Trap.
All interior parts are of forged bronze castings with the excep tion of the float which is a cast brass float tested for a working pressure of 25 pounds per square inch.
Copper asbestos gaskets are used throughout which avoid the necessity of supplying new gaskets whenever trap may be opened for inspection or repair.
MARSH No. 12 DRIP TRAP
Designed for removal of air and condensation from short steam rnains, branches or risers. Unit heaters, steam coils, etc., are within the limits of the capacity of the trap.
The size and weight of the trap permits its installation in the piping without any other means of support. Condensation is re moved through a float operated valve located at the lowest point inside the trap body. Air removal is located in the cap of the trap. Air passes through a passageway
CAPACITIES
and out through
the trap outlet.
Steam Pressure Capacities in lb. Body of trap is of
in lb..
water per hr. cast iron arid all
Vi 350 interior parts are
1 600 of forged steam
2 3
800 1200
bronze, copperand
4 1400 monel metal. The
5 1600 ther mo s t a t i c
10 15
2000 2800
member of the air
by-pass is inter-
~T"! 7
changeable with
the member of the standard No..l Radia
tor Trap.
This type of trap is particularly adapted
to Unit heater installations.
849