US1984290A - Steam system - Google Patents

Description

Dec. 11, 1934.

M. W. STOUT STEAM SYSTEM Patented Dec. 11, 1934 UNITED IsrATEs PATENT OFFICE STEAM SYSTEM Minor w. Stout, Kansas City, Mo. Application April 25, 1932, SerialNo. 607,313 5 Claims. (01. 237-67) This invention relates to improvements in steam systems, and more particularly to -an improved arrangement of steam heated apparatus in installations embodying ,a plurality of units supplied from a common source, such as a steam boiler which may be of any suitable or usual type.

The invention is presently described by reference to a steam laundry installation, employing, according to usual practice, a variety-of units such as fiat work ironers, pressers, tumblers, driers, and similar steam heated apparatus.

According to prevailing practice, when a num' ber of steam-consuming laundry appliances'are utilized as parts of a common steam system, a

steam trap or its equivalent is provided with, each unit, or group of units, so that collected condensate or water is periodically evacuated, through the trap. or necessity, a. steam trap can have but one rate of flow, under given operating conditions. Thisis true, irrespectiveof the rate at which the condensate is formed. Further numerous objections to thisuse of steam traps may be noted, in that such traps are initially expensive, notoriously difficult of maintenance, periodically result in a reduction of pressure, and hence of temperature, when the apparatus is vented, and are also wasteful of steam, due to the prevailing practice of .discharg ing the trap to atmosphere, or to a water-heater steam compartment. The use of traps thus results in an increase in back pressure, on a steam engine such as usually employed to care for the laundry power requirements, where, its exhaust is led into the same waterheater steam'compartment. Such an increase in. back-pressure onthe engine increases its unit-steamrconsumption very rapidly, which combines with the heat from the return out of the presses, tumblers, etc. to give a very poor heat balance between the heat required to heat water and the heat available for such heating; This can only mean severe heat losses to the atmosphere and also :the furnishing of laundry wash water entirely too hot for proper use, which requires consequent chilling to avoid shrinkage, loss ofcolor and other undesirable results in theclothes washed.

It is prevailing practice to lower the pressure of the condensate going through thetrap at the steamheated unit, and then to add the makeup water at this lower pressure. The power required ultimately to force .this mixture at lowered pressure back into the boiler against the high boiler pressure is relatively great. The present arrangement maintains-this boiler pressure and boosts the city water pressure up to this higher pressure.

Flash steam once formed in conventional systems at the point of pressure reduction is very diflicult and expensive to handle. Consequently it is being vented out of the return system at the first convenient point of disposal. Thi means the loss of .this much heat from the return. line, back to the boiler, where this heat properly belongs. Moreover thisvent steam is normally run to the water heater where it causes further damage and loss. I I

. The poor heat balance attained according to heretofore prevailing practice, prevents the use fheat reclaimers which take heat from t -e laundry waste water and place this heat in the fresh water before this fresh water goes to the water heater; Obviously no advantage can be gained by the use of equipment: to reduce the amount of heat required to raise'this fresh water temperature inside the water heater when there already exists an excess of heat available to heat this water. .Some plants under the prevailing practice have, as a result, such a poor heat balance that a heat reclaimer is never justified. Others with a somewhat better heat balance can justify a heat reclaimer only in periods of very low city water temperature, viz., during the winter months.

, In short all of the troubles in prevailing practice are made possible and occur because the original boiler pressure on the condensate is allowed to fallto a lower pressure while passing through the traps.

A general object ofthe present invention is attainedin a complete elimination of the'several diiiiculties aforesaid.

A further object of the invention is attained in a steam system adapted for use, for example, in connectionwith laundry equipment, wherein condensate maybe removed from the several items of apparatus, as fast as it is formed or collected.

A further objectof theinvention is attained in a material reduction initial heating time, as compared with that required under the conventional' arrangement of fiat work ironers, for example, as equipped with steam traps or usual design. I

A still further object of the invention is attained in a steam circuit in which the steam consuming apparatus is maintained, at all times, at a substantially-uniform steam pressure, and hence at a correspondingly uniform temperature.

Yet another object of the invention is attained, in a more rapid elimination of condensate from the steam consuming unit, thus conducing to hotter machines, and a greater production per machine.

An additional object of the invention is attained in the elimination of objectionable flash steam which serves, in arrangements of heretofore prevailing type, to rob the condensate of valuable heat.

The foregoing and still further objects will appear from the following detailed description, and from the drawing, wherein is illustrated, in Fig. 1 a steam system partly in diagrammatic form, as adapted for laundry use according to the present invention; Fig. 2 being a side elevation of a preferred form of pumping unit, utilized for returning condensate to the boiler.

Referring now by characters of reference to the drawing, there is employed a boiler 3, shown diagrammatically, from which is directed a steam supply pipe 4, connected through any suitable number of branches such as 5, to the various steam-consuming units, among which are illustrated in the present example, a flat work ironer 6, and a press 7. The ironer 6 is provided with a condensate return line 8, and the press with a corresponding return line 9, the several returns being directed, preferably downwardly for gravity flow, to a condensate reservoir 10. The reservoir 10 may be regarded as a manifold, and is by preference provided near or along'its top portion with a number of pipe fittings, adapted to receive the various return lines from the several steam consuming units, such as the ironer and press illustrated.

Directed from the bottom of the condensate reservoir 10, is a return pipe 11, leading directly to the inlet port of a small pump, preferably one of centrifugal type, as illustrated at 12. It is my preference to employ a pump of a type in which the pump body or housing is constructed or reinforced to withstand a pressure safely in excess of the boiler pressure utilized in the system; also to provide a stuffing box of substantial depth, as well as to provide bearings and bearing lubricants, such as will withstand the temperature of the pump compartment; it being understood as later clearly appears, that the pump operates in a line kept at substantially boiler pressure, and hence at about boiler temperature. The pump 12 is preferably of open-impeller type, so as to minimize the effect of churning, and reduce, as far as possible, impeller wear incident to the preferably continuous operation of the pump.

It is my preference also to utilize a type of pump having a horizontally directed discharge port, the discharge being connected into a return pipe 14, through which the condensate is delivered or returned, past a check valve 15, to the boiler 3. The provision of leading the discharge of the pump horizontally away therefrom, tends to avoid any objectionable steam pockets which might otherwise result, at the top or on the discharge side of the pump. Such a steam pocket would tend to cause loss of prime, in the pump. The condensate, delivered horizontally from the pump, serves to wash out any steam tending to collect at this location, and thus to keep the pump fully operative at all times.

As a convenient and preferred expedient for adding makeup water to the system, a booster pump 16 may be employed, the inlet side of which is connected to a suitable source of supply, indicated at 1'7, having connection, for example, with the usual municipal supply mains. The

discharge from pump 16 is directed, as through pipe 18, by way of a suitable check valve 19, thence into the condensate reservoir 10. A float switch 20, or its equivalent, serves conveniently, when the pump 16 is motor driven, to start the booster pump 16 as the water level 21 in the boiler 3, falls below a predetermined level.

A particularly practical arrangement for housing the condensate pump 12, is shown by Fig. 1. It is obviously desirable, particularly where the pump is electrically driven, as by a motor 22, to protect, not only the motor, but the pump, insofar as it is possible, from the high temperature of the boiler steam. In the installation illustrated, the condensate reservoir 10 is preferably disposed below the working level or floor 23, so that all water collecting in the various items of apparatus such as 6 and. '7, will be readily and immediately ,delivered by gravity, to the condensate reservoir.

To this end the reservoir is disposed below the floor 23, within a pit or like enclosure 24, of suitable depth, preferably suitably lined or brickedin, and divided into two compartments as by an insulating wall structure 25 through which extends the return line 11, leading from the condensate reservoir, to the pump 12. On the side of the partition 25, opposite reservoir 10, are located the pump 12 and motor 22. By this expedient, although the pump and piping thereto are usually at or near boiler temperature, the radiating surface thereof is small, and the motor is thus adequately protected from the heat radiated from the relatively large surface of the condensate reser- V011.

It is my preference, for convenience of installation, to mount the pump 12 and motor 22 on a common base, in direct-connected relation, as

shown in Fig. 2, although this arrangement may be varied according to the space and equipment available. The booster pump 16 may also be conveniently direct-connected to a motor (not shown) according to the showing of Fig. 2.

It will appear from the foregoing that I have provided a fully closed steam system or circuit, in which is disposed the various items of steam-consuming equipment, such as, for example, in laundry installations, flat work ironers, tumblers, driers, and all similar steam heated units. These units are thus kept under a constant working pressure at all times, and since the system is characterized by an absence of vents and traps, the usual periods of temperature drop, as occur with trap venting, are entirely obviated. The condensate from the steam units is removed as rapidly as formed through large sized lines and openings, the condensate being delivered through reservoir 10 and pump 12, back to the boiler 3. It results that the presently described closed, unvented system serves completely to obviate all trap troubles and maintenance, and pro tanto,to reduce the initial investment.

The present system, eliminating as it does all venting, serves also to prevent the transmission of an undesirable excess of exhaust steam to a water heater in those systemswhich heretofore attempted to utilize vented steam in this manner.

According to this older practice, such exhaust steam is so expensive, as a result of the use of a number of steam traps, that steam is necessarily expelled to atmosphere, in the amount which the water heater cannot condense. The present elimination of formation of exhaust or flash steam from the condensate, obviates an expensive and difficult evil, and flash steam formation with attending losses and difliculty, is effectively prevented. It will further appear that, due to the constant pressure throughout the entire circuit, the requirements as to boiler capacity, to operate a system of the present order, are much less than that in heretofore prevailing systems. It will further appear that, since the entire steam system is maintained at substantially a constant pressure, but very little power will be required to operate the condensate return pump 12; this being in fact, but very little more than the power required to work against the small head to boiler 3, and to overcome friction of the apparatus and fluid friction in the steam and condensate lines. It is contemplated that the pump 12 be operated continuously, during the time the boiler, and steam consuming units, or any thereof, are in use.

In describing the arrangements employed and shown in the drawing thereto attached and. described in the specification, I do not limit my invention to the precise form, shape or construction shown, or to the several parts thereof, inasmuch as various alterations may be made without departing from the spirit and full intended scope of the invention, as defined by the appended claims.

I claim as my invention:

1. A steam installation including a boiler, a plurality of steam consuming units piped to be supplied from said boiler, a condensate reservoir disposed below said units, and piped to receive condensate therefrom by gravity, a pump having its intake connected to said reservoir, a conduit from the discharge of said pump to said boiler, a boiler supply pump, control means movable responsively to change in boiler water level for controllingthe operation of said supply pump, and a connection from said supply pump, to said condensate reservoir.

2. In a closed steam system, including a boiler and steam consuming units, a condensate reservoir, disposed below said units so as to receive a flow of condensate, by gravity, therefrom, a condensate pump, having its inlet connected to said reservoir, and its outlet connected to said boiler, an enclosure common to said reservoir and said pump, an electric motor for driving said pump, and a wall of insulating material, disposed between said reservoir and said motor.

3. In a closed steam system for laundries and like installations, a boiler and a plurality of steam consuming units, supply pipes leading from said boiler to said units, a condensate manifold in condensate-receiving relation to each of said consuming units, a condensate pump, arranged to be supplied from said manifold, and connected for discharge of condensate to the boiler; an enclosure common to said manifold and pump, an electric motor in driving relation .to said pump, and an insulating partition, disposed between the motor and pump assembly, and said manifold.

4. In a laundry steam system, a boiler, a plurality of steam-consuming units including a flatwork ironer and a press, a condensate reservoir disposed below said steam consuming units, and pipes thereto arranged so as to keep the reservoir in open continuous communication therewith, and to deliver condensate by gravity from the units to the reservoir, a motor-driven centrifugal pumping unit of open-impeller type, having its inlet connected to the lower portion of said condensate reservoir, and disposed substantially on a level with said reservoir, a structure enclosing said reservoir and said pumping unit, and having an insulating partition between said reservoir and the pumping unit, a horizontal discharge pipe from said condensate pump, a riser from said horizontal pipe, to the boiler, a check valve disposed in the line from said pump to the boiler, an electrically driven pump for boiler makeup water, having connection to a source of water supply, and a discharge line therefrom directed into said condensate reservoir, there being a check valve in said discharge line, a float movable responsively to'changes in the boiler level, a switch arranged to be actuated by said float, and in circuit relation with the motor associated with said makeup water pump.

5. In combination in a closed steam system characterized by an absence of atmospheric vents and including a boiler, steam-consuming units supplied from said boiler, a condensate-collecting reservoir communicating with said imits, a feed pump for supplying the boiler with make-up water, a connection from the inlet of said pump to a source of fresh water supply, a connection from the outlet of said pump to the condensatecollecting reservoir, a connection from said reservoir to the boiler, and a control means for said pump operable to initiate operation thereof, responsively to a predetermined minimum water level in the boiler.

. MINOR W. STOUT.

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