US2244237A - Method and system of heating - Google Patents

Description

June 3, 1941'. G. J. BELKNAP METHOD AND SYSTEM OF HEATING Filed May 26, 1938 wlw INVENTOR 1 5'? f1 ATTORNEY Patented `lune 3, 1941 UNTED STTS ATENT GFFECE- METHD AND SYSTEM F HEATING George J. Belknap, Fairfield, fConn., assigner to The Belknap Manufacturing Company, Bridgeport, Conn., a corporation of Connecticut Appiicaufm May 26, 1938, serial No. 210,140

, (Cl. 23T-63) This invention relates to heating systems for 13 Claims.

building interiors in which a iiuid medium is circulated through loops of pipe or conduit Yconnecting with radiators located in diierent rooms of the building and connected with acommon heating apparatus usually in the basement. The y, invention further relates to methods for inverting the proportional amounts of water or other fluid medium permitted to ow through any two radiators in such a system.

The radiators in a system of this kind which are nearest the heating apparatus commonly i' tend to receive a greater share of the fluid medium iiowing from the heating apparatus than do the radiators which are relativelyrrernote therefrom. This condition cannot satisfactorily be taken care of by any established relationship of pipe sizes in different parts of the system because the amount of heat which the radiators are designed to furnish in different rooms vmay itself need to be changed to accord with some.

change in the use .to which theroom is put or to accord with varying difficulty in heating a given room at diierent seasons of the year. There are other and unpredictable factors in the heating of buildings which may call for change Y in the proportionate distribution of the heat conveying medium or fluid to the respective radiators in the system when all radiators are being supplied by a common heating apparatus through a full capacity opening of their respective control ,l

valves.

As the individual radiator control valves may be fully closed or opened to selective degrees up to their full port capacity by the occupant of a given room, this selective throttling function of an ordinary valve cannot successfully be made use of to insure desired balance or distribution of heat throughout the system as a whole. It

vhas been proposed to install choke battles within the pipes or conduits for reducing the flow ofA the system balance is required in practice makes.

such operations as these too laborious and time consuming to be feasible, and also the system must be deprived of heat While the change is being made.

One object of the present improvements is to provide in a heating system of the character described devices to determine the proportionate now ci the heating medium throughdierent radiators in such form that the changing of such device or devices requires no uncoupling of pipe connections and avoids the necessity for draining water or other heat conveying uid from the system.

Another object is to install such devices in such a system in a form to be unchangeable by any means available to the occupant of a room in which only a single radiator controlvalve is located.

Another object is to provide such devices in such form that any change of one of the devices must require the simultaneous interchanging of two such devices between any two diierent points in the system in the absence of extra parts not originally incorporated or operativeV in the system.

Another object is to incorporate such devices as concealed but removable inserts in the bodies or casings of control valves governing a pluralityl of radiators in the system.

Another object is to incorporate at least two such devices respectively within the casings of at least two valves having operating handles and other external parts of such nature, and so affected in their operation by such devices, that it cannot be known to the ordinary user of either of the valves what flow limiting eiect is produced upon the valve by the presence of the device therein, or in fact that any extraordinary flow reducing device is present within the structures ci the valves.

A further object is to provide stop devices interchangeably installable within the casings of dilierent valves in the system in a manner to cooperate with the port control member in each valve and which stop devices shall be so differently constructed that they restrict the port openings to diierent maximum capacities in different valves.

A still further object is to practice in a system of the character described a novel method of inverting the proportional amounts of` Water or other heat conveying medium permitted to flow through any two radiators in the system when the control valves of such radiators are apparently opened `to, their fullest extent and Without of necessity anecting theA proportional distribution of Water to such radiators when the said valves are less than fully opened.

A still further object is to practice in a system of the character described a novel method of inverting the relative freedom of water to iiow through two radiator control valves in the system which consists in removing from each ofv said valves a concealed part of its structure determining the maximum size of port which may be opened through the valve and reinstalling each of said parts in the structure of the other valve.

A still further object is to provide a hea-ting system incorporating radiators and valves in which a seemingly full degree of opening movement of the handles of all the valves controlling the different radiators in the system may, indiscernably tothe user of the valve, be made to result in a smaller actual size of water flow passage being opened through some valves of the system than is opened through other valves of the system, so that relatively differing distribution of water iiow tc different radiators will occur when the handles of all of the radiator valves are turned to their limit open position.

A still further object is to make possible such change in the characteristic of port opening performance of any valve responsive to an unreduced full range of opening movement of its operating handle while the entire system, including portions of the valve interior, is rllled with water under greater than atmospheric pressure and Without permitting escape of water in the process.

These and other purposes of the present improvements will appear more clearly from the following description of means by which they may be accomplished in which description reference is had to the accompanying drawing, wherein:

Fig. 1 represents diagrammatically a typical relationship of house heating radiators which may be located in diierent rooms and on diierent floor levels while connected in a suitable system of pipes or conduits leading from and back to a common form of heating apparatus in the basement which if desired may include apparatus for accelerating the circulation of water or other heating medium through the system.

Fig. 2 is a plan view of one of the radiator control valves in Fig. 1 indicating diagrammatically'a limited range of turning movement for its control handle.

Fig. 3 is a plan view of a diierent one of the radiator control valves in Fig. 1 indicating a differently located but similar range of turning movement for its control handle.

Fig. 4 is an enlarged view taken in central vertical section through the valve of Fig. 3 looking in the direction of the arrows Iand showing the valve detached from its pipe connections with itsports fully open.

Fig. 5 is a still further enlarged and perspective view of a removable stop bushing which may interchangeably be inserted within the structure of either of the valves of Figs. 2 and 3.

Fig. 6 is a corresponding view of a differently constructed removable stop bushing which may interchangeably be inserted within the structure of either of the valves of Figs. 2 and 3.

Fig. '7 is a fragmentary view taken in section through a valve containing the stop bushing of Fig. 5 on the plane 'I-'l in Fig. 4 looking in the direction of the arrows and showing'the ports of the valve as fully open as is permitted by the stop bushing.

Fig. 8 is a view similar to Fig. 'l showing the ports of the same valve as related when the handle has been turned to stop limited position in valve closing direction.

Fig. 9 is a fragmentary view taken in section through a similar valve containing the stop bushing of Fig. 6 on the plane 1 -I in Fig. 4 looking in the direction of the arrows and showing the ports of the valve as fully open as is permitted by the stop bushing.

Fig. 10 is a view similar to Fig. 9 showing the ports of the same valve as rela-ted when the handle has been turned to stop limited position in valve closing direction.

Figs. 11, 12, 13 and 14 are views taken in section on the common plane II-II in Fig. 4 looking in the direction of the arrows and show the stop lug carried by the valve stem in its several relations to the stop shoulders of the two bushings of Figs. 5 and 6 corresponding respectively to the positions of the ports shown respectively in. Figs. 'l to 10.

While the present improvements may be incorporated in either a steam heating or a water heating system, they are believed to aiord for the rst time an apparatus capable of successfully equalizing the distribution of heat to widely separated radiators in a water heating system wherein circulating water is confined at greater than atmospheric pressure and completely lls the conduits and radiators of the system. Fig. l is therefore drawn to represent such a system in which some radiator I0 may belocated at a high point, such as on the top iioor I4 of a building, and connected to an intake conduit II containing the valve I2 and to the usual return conduit I3. Another radiator I5 at a lower point in the system may connect to the same intake conduit II by means of a short stretch of branch pipe I6 inV which is located the valve IT, and may connect to the return conduit I3 through the short branch pipe I8. Thus pipes II and I3, connecting respectively to the supply main I9 at the elbow 20 and to the return main 2I at the T 22, serve as supply and return lines for both radiators, yIIJ and I5.

The supply main I9 leads from the top of the usual water jacket (not shown) contained in any form of heater unit or apparatus 23 located in the basement of a building and adapted to burn coal, oil, gas or other kind of fuel, while the return main 2l may extend to a uid urge pump 24 operated by any suitable means such as an electric motor 25, from which pump the pressure line 25 leads back to the water jacket in heater unit 23. A pump such as 24 is often omitted, leaving the water to be circulated as a mere consequence of raising its temperature in the heater 23. Such pump, employed for the purpose of speeding up the circulation of water. is apt to aggravate the tendency toward unequal distribution of heat to various radiators. Whether or'not a Ipump is used, this troublesome condition 'is successfully remedied by the pre"- ent invention.

A Ythird radiator 2'! lis shown on a common level with radiator I5 and is located in a separate loop of conduit which includes the supply pipe 28connecting to the supply main I9 at the T-coupling 29 and containing the valve 33, and which further includes the return pipe 3| connecting to the return main 2| at the T-coupling The distance through which `water heated in the unit 23 must travel to reach radiator 21 is materially less than the distance it must travel structed bushings interchangeably in various to reach radiators l or l5. Hence radiator 21 will tend to receive a greater portion of the ow of hot water from heater 23 than will the other radiators.

One example of means, which according to the present invention may be employed for attaining regulatable or equalized distribution of heat throughout the system, is inclusive of the structures shown in Figs. to 14 inclusive. In Fig. 4 the valve body or casing 33 is provided with threads 34 for connection with the supply pipe and with threads 35 for connection to the radiator. This casing and all other parts of the valve with the exception of the stop bushings of Figs. 5 and 6 are preferably alike in each of the valves l2, I1 and 3U. The casing comprises a hollow structure whose portions may or may not form an integral castingl and whose top threaded neck portion36 receives the usual hollow packing nut or cap 31 containing and adapted to squeeze the usual packing material 38 against the valve stem 39 to effect a fluid tight seal while permitting the valve stem to rotate. Stem 39 extends through an aperture in cap 31 in the usual mannerand carries fast to its fiatted bottom end 40 the roof wall 4l of a turnable, cylindrical gate 42 secured in iixed rotative relation to the stem by the nutl 43 having threaded engagement with the stem and forcing the gate wall 4| solidly against the stem shoulders formed by the flats thereon.

The cylindrical gate 42 is hollow and is open at its bottom end.- Its lateral wall contains the port aperture 44 which is turnable to and from register with the lateral passage 45 in casing 33 leading toward the radiator. Gate 42 bears rotatively against the cylindrical surface of the casing interior and is held upwardly in its position shown in Fig. 4 by the peripheral flange 46 on the valve stem 39 whose downward thrust is borne by a cross wall-41 apertured to-pass the stem and counterbored from the top for nesting the flange 46 of the stem.

A ring 48 of resilient packing material such as rubber or suitable composition, reinforced if desired by a fibre or fabric layer or facing, surrounds stem 39 between cross wall 41 and the roofwall 4I of gate 42 and may be pressed .upwardly against cross wall 41 by a ring-like ridge 49 projecting above the otherwise flat roof wall 4I.l Ridge 49 surrounds the valve stern and 1s radially spaced therefrom and from the inner cylindrical surface of the valve casing. By this `construction a fluid tight seal is produced at a point in the valve casing which -precludes the water or other heating medium controlled by the valve, even if under considerable pressure, from reaching the bearing of stem 39 in cross wall 41 and escaping therethrough.

Above cross Wall 41 the neck portion 35 of the valve'casing is bored to form-a cylindrical pocket which may contain either of the stop bushings of Figs. 5 and 6. These bushings are examples of differently constructed stop devices which for the novel pur-poses of this invention may be im- `mured within the valve structure for determining the maximum range of turning movement, as well as the positive location of the extreme or limit positions of valve stem 39 in relation to the valve casing, and hence of port `44 in relation yto the lateral passage 45. According to the present invention, the stop bushings in different valves differ in construction but not in a manner to prevent the insertion of these differently convalve casings of like construction.

Referring more particularly to the stop bushing 50 of Fig. 5 and to the differently constructed stop Abushing 5l of Fig. 6, these bushings may be alike in every respect except that the circumferential relationship of laterally projecting fins 52 to shoulders 54 and 55 on bushing 55 differs from the circumferential relationship of like projecting fins 53 to stop shoulders 54 and 55 on bushing 5I. Shoulders 54 and 55 are formed by the similarly cut away -portion of the cylindrical wall of bushing 55 and bushing 5l, which provides room above the cross wall 41 of the valve casing for the sweep of a stop lug 55 xedly carried by the valve stem slightly above flange 46 thereon. Stop lug 55 is thereby adapted to abut against bushing shoulder54 in the fully closed position of stem 39 and of its fixedly carried operating handle 51, while the same lug will abut against bushing shoulder 55 in the fully open position of stem 39 and handle 51.

Each of bushings 50 and 5I is freely slidable lengthwise of the valve stem and aord bearing therefor. The fins 52 of bushing 50, and in like manner the iins 53 of bushing 5I, are freely slidable vertically in splines or keyways broached or otherwise produced in the inside face of the neck portion 36 of the casing but fit these splines in a way to lock the bushing against rotative movement relative to the casing. Preferably neither the splines 58 nor the fins 52 and 53 are in diametrical alignment so that bushings 53 and 5I can each be inserted in only one rotative position relative to the casing.

It is shown in Fig. 4 that the top end of bushing 5i) or 5l which includes the circumferential groove 59 projects above the top end of the neck portion 36 of the casing. This top end of the bushing becomes embedded in the packing material 38 of cap 31 when the latter is screwed down firmly on the casing neck 36 and this packing material is squeezed downwardly against both the top of the 'bushing and the top of thecasing neck thereby sealing all cracks atthe juncture thereof. The bushingis thereby retained in the hollow of the casing neck with its bottom end 6l] seated firmly against the toprof the cross Wall 41 of the casing. When the stop bushing is to be removed, valvehandle 51 is released from its squared engagement with the top end of stem 39 by removing screw 6| after which the handle can be removed from the valve stem. Packing nut 31 Will be unscrewedfrom the casing neck 36 during which operation the stop bushing 50 or 5l will separate from packing 38 because the latter turns with the cap while the former is kept from turning by its locked fins 52 or 53. When the cap 31 and packing 38 are removed by lifting them o over the top end of the valve stem, the stop bushing is left with its grooved top Vend projecting from the casing neck and may easily be pried upwardly and lifted out of the valve casing and is free to slide upwardly on the valve stem and likewise be removed from the top thereof. A different stop bushing may now be inserted within the valve casing and the parts restored by a reversal of the operations described.

Having described the structural features of differently constructedstop devices and the manner inwhich they may be installed interchangeably forcooperation with the port control member of otherwise similar valve mechanisms, the cooperation' of these structures, devices and mechanisms in a heating system containinga plurality of valves can be explained.

In Fig. 1 by way of example it may be assumed that radiator l is installed in a building to heat a little-used room while radiator 21 may lbe depended upon to supply heat for a constantly used room whenever the heating system is in operation. For the purpose of sacrificing the flow of the heating medium through radiator I0 in favor of a dependable supply of the heating Ymedium to radiator 21, valve l2 is equipped with the stop bushing 5I which limits the maximum capacity of the port opening to that shown in Fig. 9 when the valve handle is turned to its open limit position, while valve 30 is equipped with the stop bushing 55 which permitsthe greater opening through port 44 to passage 45 shown in Fig. '7. Occasion arises for the little-used room to be constantly occupied and it is decided vthat in the characteristic performance of the system as a whole, heat can best be spared from radiator 21 to insiu'e a greater and more dependable supply of the heating medium to radiator I0, Thereupon the engineer in charge of the heating plant will remove bushing 5I from valve l2 and install it in valve 30 at the same time transferring bushing 5D from valve 30 to valve l2 in the manner hereinbeiore described. Valve l2 may now be opened to the full extent of the capacity of port 44 as shown in Fig. 7 while valve 30 will be restricted to the less maximum capacity Of DOTT' opening shown in Fig. 9.

This single example of a practical use for the present improvements in a heating system is but illustrative of a great many occasions which constantly arise for varying the distribution of the heating medium to different radiators. In systems incorporating many radiators normally supplied by a common heating plant working at normal capacity, a reversal of any two stop devices such as the bushings 50 and 5I between any two radiator control valves will involve no requirement for increase in the heating capacity of the plant but will effect a change in the relative distribution of supply to the radiators concerned and without of necessity causing any change in the supply of heating medium to those radiators whose valves remain as before. The possibility of interchanging the stop devices between any two radiators in the system gives to the engineer in charge a wide choice as to the two particular valves whose stop devices shall be interchanged. Naturally a record of the existing installation of stop devices in the diiferent valves will be kept up to date Vto accord with all interchanging of the stop devices which has been made in the system. It will be understood that in practice, stop devices having as many gradations of relationship between the casing heldins 52 or 53 and the bushingstop shoulders 54, 55 as are required may be employed, eight diierent constructions of stop bushing embcdyingeight dierent such gradations being found useful in practice. For convenience the stop bushings of each different construction may be stamped with suitable index numbers as a key to the degree of maximum port opening they will'permit.. Such degree may in different stages be greater or smaller Vthan the extent of port opening shown in Fig. 9.

Ittherefore becomes ,plain that my improved construction, nature, and relationship of devices for changingthe capacity heating performance of different radiators selectively without unbalancing the system asa wholegive rise to very desirable features which have not heretofore been available in heating systems. First, because of the iiuid sealing effect of the inner packing ring 43, the stop bushings may be interchanged while the interior of cylindrical gate 42 and the valve passage 45 are full of water at greater than atmospheric pressure thus making possible the removal of the valve cap 31 without draining the water from the system. Second, the effect of replacing one stop bushing with a diierently constructed bushing does not vary the angular range of movement R in Figs. 2 and 3 which is performed by the valve handle 51 but only varies theclosed limit position C and the open limit position O to which the handle and valve stem are permitted to turn `in relation to the valve casing. As radiator valve handles are commonly round and without markings of any kind to indicate their rotative position and since the range of permissible movement of the handle is. not varied, remaining always say, a half turn, it will be imperceptible to the user of any individual radiator that any change has been made in the control valve. Third, even by willful tinkering the occupant of a single room has no means available to change the iiow affecting characteristics of the stop bushing in a single radiator control valve because of the absence of adjustable parts and because he will not have available a differently constructed stop bushing with which to replace that contained in the valve. l

Additional features include, fourth, that the means herein proposed for restricting or reducing the maximum opening of the valve ports in no way prevents or interferes with the ability to adjust the size of the port'opening by movement of the valve handle to any desired setting less than the maximum port capacity determined by the stop bushing. Fifth, in the absence of an extra supply of stopV bushings additional to those originally installed in the system, the engineer in charge is restricted to interchanging the bushings between the different valves and cannot by an unwise use of a different aggregate of bushings disrupt the composite sizes of conduit passages for the circulating water or other heating medium in the system as a whole. Sixth, nevertheless when occasion demands, by introducing new stop bushings into the system, changes in the heating plant itself may be compensated for without repiping any part of the system. Such changes might reside in the installation of a new boiler or heating unit of different heating capacity than the old, and in the introduction or elimination of apparatus for increasing the circulation such as the circulating pump 24.

It will be noted that Figs. 2 and 3 are views looking downwardly upon the valve in which the valve handle turns clockwise vto close the valve and counterclockwise to open the valve. In Figs. 7 to 14, inclusive, this direction of turning of the parts is reversed because these sectional views are representations of the parts in each case looking upwardly with respect to the valve handle.

Having described the present improvements in one structural form for the purpose of explaining Ythe principles underlying the invention, it will be understood that many modifications of the structure described and many possible substitutes therefor will be suggested to those skilled in the art by the presentV disclosure. The appended claims are intended to embrace all equivalents, modifications and substitutes which come within the scope of the invention and fall fairly within their terms. I

' I claim: l

v1. The method of inverting the proportional amounts of a circulating heat conveying medium permitted to flow in a heating system through dilerent conduits each incorporating a movable port control gate and an associated device removable from the conduit, which consists in fixedly predetermining by the use of said devices diierent locations of the permissible ranges of back and forth movement of said gates relative to their respective conduits, and then interchanging the said devices between said different conduits in a manner to invert the predetermined eiect of said devices upon said locations of said permissible ranges of gate movement.

2. The method of inverting the proportional amounts of a circulating heat conveying medium permitted to ow through diierent radiators in a heating system respectively controlled by flow modulating valves each having a separate operating handle and an associated device removable from the valve, which consists in ixedly predetermining by the use of said removable devices diierent rotary locations of the permissible range of valve opening and closing movements of said handles in relation to their respective values, and then interchanging sai-d devices between said valves.

3. A circulating fluid heating system including in combination, a source of fluid flow, conduits constructed to form a plurality of loop-like fluid passageways connected to receive iluid owing from said source and to return the uid thereto, a flow throttling gate turnably mounted in each of said passageways and having a manually operable` extension reaching to the outside of the conduit structure which forms the passageway, and' stop means mechanically associated with each conduit structure in a manner to limit the turning of each of said gates to a xed range of back and forth movement restricted by said stop means to a single possible rotary location relative to its passageway said location being diierent in respectively different passageways and said stop means embodying devices constructed to be mutually interchangeable between at least two of said passageways.

4. A heating system comprising in combination, means for circulating a heating medium, a plurality of loops of conduit connected to form diierentl passageways for receiving a il'ow of said medium from said means and for returning it thereto, space immuring structure forming a chamber adjacent to and oiset from the passageway in each of said loops of conduit, a flow governing baiiie movably mounted in each of said different passageways having an operating element extending into the chamber adjacent thereto, devices located respectively in each of said chambers constructed and arranged cooperatively with the respective operating elements of said baflies to limit to a single xed point in relation to a given passageway but to diierent points in relation to respectively different passageways the flow increas ing movements of said baiiles, and means for stationing said devices respectively in said chambers in a manner to permit the selective interchanging of different devices between different chambers.

5. In combination with a heating system as dened in claim 4, means constructed and arranged to effect a iluid tight seal between each of the said chambers and its adjacent conduit passageway in a manner to preclude escape of the said heating medium from said passageway into said chamber, thereby to enable said devices to be interchanged while said passageways are full of the heating medium.

6. In a heating system including heating apparatus, pipes for conducting a flow of heat con veying fluid and radiators connected in the system at respectively diierent distances from the heating apparatus; in combination, a plurality of uid i'low control valves piped to control respectively different radiators, each valve including a handle-operated fluid ow control gate turnable through a like range of movement between closed and open limit positions, and devices similarly constructed in certain portions enabling them to be interchanged between said valves and differently constructed in other portions enabling them to predetermine a single definite limit position for the said control gate dilerently located in difierent valves in relation to the bodies of said valves.

'7. In a fluid circulating heating system for building interiors including a plurality of radiators, in combination, a plurality of valves for separately controlling the flow of uid through respectively different radiators, each of said valves including a gate operative to control the passage for uid through-the valve, a stem in each of said valves connected to operate its gate and arranged to be turnable through a like range of movement in each of said valves between a limit position for closing said pass-age and a limit position for opening said passage, and devices constructed and arranged to be selectively interchangeable between said valves and operatively associated respectively with the stems thereof in a manner to predetermine and restrict said limit positions to constant but diiering locations in each of said valves.

8. In a uid circulating heating system for building interiors, the combination defined in claim 7 in which the said devices are immured within the valve in a manner to be concealed from the user of the valve and inaccessible without the use of tools.

9. A heating system including, in combination, conduits lled with water adapted to circulate through the system under a common head of greater than atmospheric pressure, means to heat said water and cause it to flow through the passageways of different sections of said conduits, manually operable ow control gates turnably mounted respectively within said passageways each of said gates containing a flow control port turnable into register with its conduit passageway, and means for varying the proportional distribution of water ow through different sections of said conduits embodying a device mechanically associated with each of said gates constructed and arranged cooperatively therewith to limit to a single predetermined size the portion of said flow control port that can be turned into register with the conduit passageway, said devices being mutually interchangeable and diiering in construction in a manner to permit a diieren-t portion of the respectively different flow control ports to be aligned with their respective passageways.

l0. A water heating system as dened in claim 9, in which each of the said gates has a manual operating element extending outside the conduit passageway, and in which each of the said devices is located outside the conduit passageway in uid isolated relation to the water contained under pressure in said passageway.

11. In a heating system'n which aV heating medium is circulated through loops of conduitl arranged to lead said medium from a common source of heat through respectively diierent radiators and back to said source of heat, in combination, at least two valve bodies connected in respectively diierent loops of said conduit, a movable port control member in each of said valve bodies equipped with an operating handle exterior thereto, and stop devices respectively installed within said valve bodies in a removable manner and arranged to limit to a fxedly stationed range of port controlling movement the handle equipped member therein, each of said stop devices being similarly constructed in one portion thereof in a manner to establish each device in a like xed relation to each body of the different valves, and each of said devices being constructed dilerently from the other device in a, different portion thereof for cooperating with said port control members in a manner to restrict the ports controlled thereby to openings of different maximum capacity in respectively diierent valve bodies, whereby the maximum capacities of port openings in two of said valves may be relatively inverted by interchanging said stop devices between said valves.

12. In a house heating system, the combination with a series of pipe-connected radiator control v alveseach having a body and a handle-rotated stem for opening and closing the va1ve,of a seriesl of stop members constructed to be interchangeably applied to said valves respectively and further constructed and arranged to limit the range of back and forth turning movement of the chamber contained valve stem to less than S60-degrees, said stop members differing in construction from one another in a manner to predetermine a, single fixed location oi said range of turning movement differently related to the valve body of respectively diflerent valves in the system.

13. In a house heating system, the combination with a series of pipe-connected radiator control valves each having a body containing a chamber and each having a handle-rotated stem extending into said chamber for opening and closing the valve, of a series of stop members constructed to be interchangeably insertable and xedly held within the respective chambers of said valves and further constructed and arranged to limit the range of back and forth turning movement of the chamber contained valve stem to less than 360- degrees said stop members differing in construction from one another in a manner to predetermine a single fixed location of said range of turning movement differently related to the valve body oi respectively different valves in the system.

GEORGE J. BELKNAP.

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