US1916696A - Vacuum air valve for vapor heating systems - Google Patents

Description

y 1933- c. w. STEWART 1,916,696

VACUUM AIR VALVE FOR VAPOR HEATING SYSTEMS Filed Oct. 9, 1930 Patented July 4, 1 933 MT nST'ATE-s v cm-muss w. STEWART, or \VATERBURK'. CO NNECTI CUTQASSIGNOR ITO HOFFMA AT NT OFFI E-1* T SPECIALTY, GOMPANY,. OF .WATERBURY, CONNECTICUT, A CORPORAT ON. or

: ILLINOIS v VACUUM AIR VALVE'FOR VAPOR HEATING SYSTEMS Application filed October 9, 1960. Serial No.'487,440.

The present invention relates to valves adapted for application to steam heating systems for the purpose of releasing'air from the i return line of-the' system, "checking the entrance of air to such return line, andprevent ing escape to the atmosphere of steam which, under certain conditions, may find its' way into the return line. Its object is'to furnish a Valve of exceedingly'simple principles and construction, and more specifically one con trolled jointly by pressure and temperature,

which will function under normal conditions to release air from the return line and prevent its entrance when-the vapor pressure in the 13 system is'lower than atmospheric; and, under conditions when-the supply steam pressure rises above the normal differentialover the return line pressure, will prevent loss of system equipped with a cross-over device for permitting passage of steam under certain conditions from the pressure side to the return line of the system. v

According to this disclosure the valve of my invention is connected with the hlgh po nt of the dry return line of the system, with which the cross-over device is also connected substantially as-and for the purpose set forth in the patent of Ralph "R. Emerson, No. 1,639,084, August 16,1927. I

Inthedrawing, Fig. 1 is an elevation of a heating boiler and the steam and return connections adjacent thereto, showing my novel valve connected in the dry returnline;

Fig. 2 is a-sectional view of the valve and the immediately adjacent'pipe connections, showing the valve and its associated parts in the position of equilibrium at pressure and temperature; 1

Fig. 3 is a'view ofthe same nature but of which the adj acentpipesection' of the dry showing the operating'parts as affected by vacuum conditions; r

same

-clos'ed, in association with'a vapor heating atmospheric Fig. 4 isa further view ofthe same eharacte'r but'showing-the parts in the position occupied when steam is passed into there- 'turn line in consequence of avacuum therein.

' Like reference characters designate the parts-wherever they occur mall the figures. i v j Referringto the drawing,'10represents a steam boiler of any suitable character adaptedtofurnish. steam at low pressure for heat ing purposes. 11" is thefbeginning of the steam main bywhich boiler steam is conducted'to the heating radiators. 12 is the high end of the'dry return line'which makes 1 a circuit of thebuilding inparallel with'the steam main, and is coupled with the return outlets of the radiators, finally joining the Wet return line 13. 14 is a cross-over device substantially similar to the" differential loop shown in the patent of "George D. Hoffman, No; 1,572,482, February 9, 1926, connected pipe 15 and having an overflow drip connection with the 'boiler through pipe 16. The

blow over'steam space of" the loop is connected by a pipe 17 with the high end-of the dry return line 12.- This combination is essentially like that described" in the above named Emerson patent and has the same functions and results. That is, whenever'the boiler pressure exceeds the return line pressure by more than a prescribed differential, for which theidifferential loop is designed or set, enough steam is allowed to pass the prescribed differential. Such an excess may .occur either by producing too hot a fire inthe at 18. It consists of a casing having .p'ro- VlSlQIiS forconnectmnwith the'dry'return line and the blow-over device; as for instance,

threaded openings at opposite side'sinto one returnline 1-2 is screwed and'in the other-of which a nipple'l is screwed to connect with 70 with the steam space 'of the boiler through loop to equalize such excess and restore the the pipe 17 from the blow over device. In the top of the casing is a vent opening 20 having a valve seat to which an outwardly opening vent valve body or member 21 is fitted. A pressure-responsive member 22 and a stop 23 are mounted in the lower part of the valve casing. Such pressure-1'esponsive member is in this embodiment a metallic bellows open at' its outer end to the atmosphere and closed at its inner end. However, other equivalent members may be used, such as a flexible diaphragm, all of which are typifled by the specific bellows here shown. To the closed inner end of the bellows is secured a stem 24 carryin an expansible thermostat 25, which in this instance consists of a series of connected drums having flexible end walls and containing a Volatile fluid. Other thermostats of specifically different construction may be used, however, such as a chamber of bellows type, all typified by the one shown. A'stem 26 secured to the upper end wall or diaphragm of the innermost drum is connected with the stem 27 of the check valve by any suitable lost motion connection, such as a pin 28 on one of the stems and a slot 29 in the other stem receiving such pin.

The bellows 22 isessentially a pressure responsive member subjected on its outer side to "the pressure of the atmosphere and on its inner side to the pressurein the return line. Various equivalent pressure responsive means usable to like efi ect in place of such a bellows will occur to persons skilled inart, but I prefer the bellows type on account of its ability to collapse and expand through a considerable distance without overstrain and under the influence of modleratex pressure difl'erences.

in the return line. Such stop is here shown as an inwardly turned. 11p on the mner'end of a tube passed through an opening in the under side of the valve casing and suitably secured inch, or any other desired distance within the range of movement of the bellows. The pin and slot connection, or its equivalent, is so designed and located that an equal amount of lost motionis provided for in the same direction; that is, the bellows may be we panded to the limit permitted by the stop without causing the check. valve to be unseated. There is also sufficient lost motion in the opposite direction to permit opening of the-check valve by the air at a pressure higher than atmospheric within the return line,

which may collect in the system under normal operating conditions. The expansive movement of the thermostat is limited to less than The stop 23 is provided to limit its inward movement when a vacuum occurssuch total lost motion within the range of temperatures developed in the system.

In the normal operation ofthe heating system, the pressure dilii'erential between the boiler and the return line does not exceed, but most of the time is well below, the prescribed maximum, which is usually established for va aor heating systems at 10 ounces per square inc '1. However, the return line pressure may be slightly above the atmospheric pressure when a brisk fire is maintained inthe boiler, or below atmospheric pressure when only a small amount of "heat is generated in mild weather. The check valve, which is normally seated, prevents entrance of air under vacuum conditions but is'free to open and permit release of accumulated air when the pressure rises above atmospheric; and is light enough in weight and large enough in area to be thus opened by a very slight excess of internal pressure, say'ah'outone quarter of an'ounce per square nch.

The novel purposes and accomplishments of the invention areto prevent the check valve from opening .and releasing steam when the boiler pressure is accidentally raised above the prescribed maximum, and to cause opening of the valve so as to break the vacuum in the return line when a vacuum occurs therem so rap1dly and of such degree as to cause flow of steam past the cross-over device into the return line. Both of these conditions are abnormal and, exceptfor the cross-over device or loop, would be dangerous bycausing water to -leave the boiler. A

When the first of theseconditions-occurs,

the steam pressure'acting on the bellows 22, i

which is substantially larger in area than the check valve, displaces the closed end of the bellows outwardly, taking up the lost motion in the connection withthe valve and forcibly holding the latter on its seat. Although at the same time the .heatoi' the steam expands thermostat 25, such expansion is absorbed by continued movement of the bellows, a sufiicient range of such movementbeing provided by the design and placement of the bellows to accomplish this purpose. Thus the steam passing'into the return line is prevented from escaping and caused to build up quickly therein thenecessarypreszie sure for holding the water in the boiler. As,

under these conditions, the return line is already full of air at atmospheric pressure,the increase of pressure needed to hold the boiler water is obtained by com-pression'oi this air, and only-a small amount of steam is needed thus tocompress it.

The second of-the above na-med'abn'ormal conditions occurs, for instance, when radiators are shut off at night; in sleeping rooms and windows are opened); Then high vac- }uum is quickly formedinsuc'h radiators'and also in the return linedue the opening of the.trapsfin ra'd'iators:for release of con densation. Such quickly formed vacuum adapted to achieve'the desired results.

causes a sudden increase inthe pressure differential of thesystem, for the boiler pressure is not simultaneously decreased but may even be somewhat increased due to there-duction in the demand for steam. So the crossover deviceipasses steamto the, return line, just as it does when the boiler pressure is raised too high. But at this timethe return line contains littleor no air to compress so that, if the check valvewere not opened, a large volume ofsteam would be needed to build up the return line pressure to prevent backing of water. from the boiler, and the steam filling the return line would cause objectionable noises. These noises are caused by clicking or chattering of the return line valves or traps'on theradiators, due to the effort of thesteam in the return line attempt- 'ing to flow into the radiators, counter to the water of condensation which is attempting to flow from the radiator into the return line. But these :objectionableand dangerous effects are prevented by my inventionthrough the conjoint action of thebellows 22 and thermostat 25, which open the" check valve and allow air to enter and break the vacuum immediately after steam, enters the return line. In the performan'c'efoi this conjoint action, the vacuum condition in the return line first pulls the bellows inward to the limit established by sto'p23', as shown in Figs}; and 4, thereby taking up all the lost motion between the" thermostat and. check valve, and then the heat of the steam entering the return line expands the thermostatand opens the valve, as shown in Fig. 4.

lVhile I have shown illustrativelyan operativeembodiment of means for carrying out the invention, it is to-be understood that I am not limited to this-particular embodi ment, but that instead I desire to protect all means of the same or equivalent principles For instance, wide variations in the relative arrangement of the several parts of the-device and of theconnections between them may be made, and the check valve may be arranged to be normally closed by a light spring or other yielding actuator instead of bygravity. A lost motion connection of some character between the check valve and its controlling means is important, however, in order to prevent the inward distortion of the pressure member from openingthe check valve under normal vacuum conditions.

hat I claim and desire to secure by Let ters Patent is I s 1. valve adapted to be connected in the ber normally closed across said vent to prevent entrance of the outer air into the casing and adapted to be opened by excess pressure therein for venting of air therefrom, and

control meansfor'said valve member comprising a pressure responsive member movable in one direction by excess pressure in the casing and in the opposite direction by excess atmospheric pressure, a thermostat connected 5 to said pressure responsive ,member to be moved thereby, and lost mot-ion connecting means betweenflthe thermostat and .valve member.

2. A valve adapted to be connected inthe return line of a steam heating system comprising a casing, a valve member normally closed to prevent entrance of the outer air into the casing and adapted to be opened by excess pressure therein for. venting of air therefrom, and control means for said valve vmember comprising a pressure responsive member movable in relatively opposite directions by the internal pressure in the casing and the external atmospheric pressure when either exceeds the other, a stop for limiting gtheatmospheric pressure induced, displacement of said member'from its position of equilibrium, a thermostat having a lost motion connection with said valve member and being coupled with the pressure responsive member to be moved in opposite direc tions thereby and having an independent heat induced movement as to its portion which is thus connected to the valve member, which movement is'less than the range of movement of the pressure, responsive member, the movement of the pressure responsive member by exc-esslpressure in the casing being applied through said lost motion connection to hold the valve member closed, and its movement responsive'to excess atmospheric pressure be,- ing in the direction for opening the valve, but the lost motion of the connection in that direction being'as great as the permitted movement of the pressure responsive member, p v a 3. A vacuum check vent Valve comprising a casing'having a vent'opening, a valve body controlling said. opening and combined thermostatic and pressure responsive members co'njointly associated to control said valve body and having alost motion connecion therewith. v j i 4. A vacuum check vent valve comprising I a valve casing having a vent-opening, a valve body controlling said opening, a pressure respons ve member mounted in the valve casing to be moved outward by excess of internal over external pressure, and inward byexcess of external pressure, a thermostat carried b sald pressure responsive member, anda lost motion connection between said thermostat and-valve member. n g

5. A valve as set forth in claim 4 in which the lost motion connection is arranged to apply closing force to the valve member when the pressure responsive member is displaced by excess of pressure within the valve, and. to open the valve member when the pressure organized to apply closing force to the valve member when the pressure responsive member is displaced by excess of pressure in the valve, to permit displacement of the pressure responsive member by excess of external pressure without opening the valve member, and to cause opening of the valve member when the thermostat is distorted by heat at the same time that the pressure responsive member is displaced by excess of external pres sure. a

7. A valve of the character described, com} prising a casing adapted for connection with a pipe line and having a vent opening at one side, a valve member cooperating with said vent opening, a pressure responsive memberat the opposite side'ot the casing exposed to the pressures inside and outside of the casing, a thermostat carried by. said pressure responsive member between the latter and the valve member, being expansible by heat, and having a lost motionconnection withthe valve member. I

8. An air venting vacuum check valve for use in a steam heating system comprising a casing having a vent to the outer atmosphere, means adapted to close'said vent when the external atmospheric pressure exceeds the pressure within the casing, and means for opening the. vent to admit air when steam enters the casing during the existence of a vacuum condition therein.

9. An air venting vacuum check valve for use in a steam'heating system comprising a casing having a vent to the atmosphere, a valve normally closing said vent to exclude the outer air but adapted to be opened by slight excess of pressure within the casing over the atmospheric pressure, and thermally actuated means within the casing tor opening said valve positively when steam enters the casingduring the existence of a vacuum condition therein.

10. Anair venting vacuum check valve for use in steam heating systems comprising a casing having a vent to the atmosphere, a check valvebody normally closing said vent to exclude outer air from the casing and adapted to-he opened by a slight excess of the pressure within the casingover the external atmospheric pressure, means for opening said valve when the steam enters the casing during the existence of a vacuum condition therein, and means for closing the valve.

when the pressure within the casing is greater than that which causesthe valve to be opened. v

11. An air venting vacuum check valve for use in the return line of a steam'heating system comprising a casing having a vent to the atmosphere, means to prevent inflow of air through said vent adapted to permit outflow of air when the pressure within the casing is slightly greater than the external atmospheric pressure, means for positively opening the vent to admit external air to the casing when steam enters during existence of a vacuum condition within the casing, and means for positively closing the vent when steam enters the casing during the existence therein of a pressure approximating the atmospheric pressure. v

12. An air venting vacuum check valve for use inajsteam heating apparatus comprising a casing having a vent to the atmosphere, a check valve body adapted to be closed by superior external atmospheric pressure and to be opened by a slight excess of internal over member exposed to the pressures inside and outside of the casing for movement in relatively opposite directions according as one pressure or the other predominates and a thermostat carried by said pressure responsive member and coupled with the valve body for opening the vent when the steam enters atmospheric pressure, a pressure responsive the casing during a vacuum condition therein and for holding the valve closed when the internal pressure considerably exceeds the external pressure.

13.- A valve for use on the return line of a low pressure steam heating system to vent air and prevent inflow of outer air into the line, comprising a casing having a vent, a valve body coupled with said vent adapted to be closed by superior external-pressure and to be opened'by a slight excess of internal over external pressure, a thermostat and a pressure responsive member coupled to one another and to the valve body in series with provislon for a limited-amount of lost motion, said pressure responsive member being secured to the casing and exposed to the pressures within and without the casing for movement in relatively difiierent directions according as one or the other of said pres sures predominates. I

In testimony whereof I have aflixed my signature.

CHARLES w. s'rnwaar;

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