US2253588A - Vent valve for steam heating systems - Google Patents

Description

, Aug. 26, 1941.

. w. K.- sIMPs N 2,253,588

VENT VALVE FOR STEAM HEP TING SYSTEMS Fiied Sept. 14, 1938 'is to valves of this type tofore produced for the same purpose,

'izes, causing the valve' to close.

Patented Aug. 26, 1941 UNITED STATE s PATENT OFFICE VENT VALVE FOR STEAM HEATING SYSTEMS 4Claim5. (Cl. 137-422) This invention relates to valves for use in connection with radiators and other parts'oi steam heating systems for releasing air therefrom while preventing escape of steam and water. Many valves for this purpose are provided with a com-- bined float and thermostat organized to close the valve when heated to a temperature approximating that of live steam, and also when water at any temperature rises in the valve casing. It that the invention relates. Embodiments of the invention designed particularly for mounting on a steam heating radiator are shown in the drawing and described in the following speciflcation'for illustration, but without intent to limit myprotection to that specific use only.

The'main object is'to furnish a valve of this type of simpler design and less costly construction than the best of the commercial valves herewhich will function approximately as well as the more complicated valves having a greater number of parts heretofore found necessary to accomplish the same operative results. In order to explain the results obtained and the. inventions embodied in the means which I have here devised to obtain them, it is necessary to touch briefly on the diiflculties encountered in the venting of radiators.

These dimculties are due mainly to accumulation of water in the vent valve casing to a considerable height above the-drainage outlet. No trouble is found in valves which will operate perfectly so far as thermostatic action alone is concerned. In such valves the float member is supplied with a small quantity of volatile fluid which vaporizes and condenses within a narrow temperature range slightly below the steam temperature, and is made with a flexible wall constituting a dia-- phragm which is bulged out when the fluid vapor- On reduction in temperature the reverse action occurs, allowing the valve to open unless the float is held elevated by an accumulation of water. Hence, only the conditions causing water accumulation, and the effects thereof, need be discussed here. They are as follows.

Some designs of ators which remain filled periods, will load up with water produced by condensation 'of the steam Proper drainage of this condensate from the valve back into the radiator is necessary to permit opening of the vent port when steam contact ceases. Also when water surges'into' the radiator and enters the valve valve, when attached to radiwith steam for long making thermostatic float.

casing, prompt drainage is required to obtain the desired rapid venting of the radiator. A radiator is said to work water" when, in filling with steam, water surges into itand subsides at frequent intervals. The water entering the vent valve at such times closes the outlet port by float action, and unless it is drained from the valve between surges, air then trappedin the radiator cannot escape. So it is necessary that the valve be cleared of water frequently, and during the intermittent opening and closing of the port no water should escape to damage walls ,Radlator valves of the float-thermostat type heretofore commercially used have had high water lines; that is, the height ofwater which causes the vent port to be closed has been con-' siderably above the connection from the valve to the radiator. As water starts to drain from such a valve, reduction of the pressure in the space above the water line commences, due to expansion of the confined air into the space vacated by the water. The radiator pressure, however, opposes' such expansion so that, in the absence of effective provisions for counterflow of water and air, most of the water remains in the valve and the vent port remains closed. The valve is then said to be water-logged, and venting cannot occur unless air is permitted in some way to pass from the radiator into the valve space above the water. Means in the nature of internal shells and partitions, and other complications of design, have been successfully employed heretofore to provide separate'channels for air and water whereby air is conducted without interference to a point, above the highest water level and effective drainage of the valves is secured. But in valves without such shells or the like, venting can occur only by bubbling of air through the water-seal in quantity sufficient to'equalize the pressure in the air valve with that in the radiator. In practice this is prevented by conditions of installation which require air to travel horizontally for approximately an inch or more before it can rise through the water, and such valves become water-logged and inefllcient, if not entirely nonoperative when fllled with water, above the flotation line The problem solved by this invention is to avoid water-logging from the causes above referred to, effect free drainage without the complication of interior partitions, overcome the effects of water-logging due to leakage consequent on the vent valve failing to close tightly,

space of the and cause the valve to vent without spitting.- This problem is complicated by the fact that standardized conditions limit the diameter of the passage through the connecting nipple to approximately A".

In my studies of the difiiculties and problems above referred to, I have devised means by 'which water-logging of vent valves may be avoided and efllcient drainage accomplished .without the use of internal partitions of. any

' sort; hence with fewer parts and less-expensive scale of a radiator valve of the so-called angle shank type embodying the invention, the plane of section being vertical when the valve is in the position of use;

.Fig. 2 is a perspective view of the vent port fitting or plug detached from the, body or casing of the valve;

Fig. 3 is a perspective view of the nipple which is connected to the side of the valve casing for attaching it to a radiator;

Fig. 4 is a perspective view of an orifice memher, which is also a locking element by which drainage is controlled and a siphonic drainage tube is retained in the nipple with provision for slippage to accommodate different conditions of use;

Fig. 5 is a sectional view showing the manner in which the drainage tube is assembled with the locking device shown in Fig. 4;

of the bore l4. Its outer end is adapted toenter the radiator to which the valve is attached and to hang down therein. The float contains vol- 'atile fluid and is constructed with a bottom wall,

forming a diaphragm, which is adapted to bulge outward when the volatile fluid is expanded by heat. When the valve casing is free from water, the diaphragm rests ona boss I2 .rising from the base; and when it is cold also, the extremity of the valve pin is withdrawn from the seat.

The valve thus far described is similar in some respects to many now on the market. It differs in respect to the positions of the water levels of float flotation and valve closing relative to certain factors of the valve structure, and in other features presently to be described. The base of the valve casing now being described is depressed below the bore of the nipple 3, and the inner end of the nipple is made with an enlargement containing a chamber l3 opening into the valve casing, of which the uppermost point is substantially higher than the top of the bore ll, the latter being of the diameter prescribed by standard practice. (While such enlargement is a preferred feature, the bore ll or its equivalent may be carried straight through to the interior of the casing, in valves of different proportions, within the scope of the invention, as

Fig. 6 is a fragmentary perspective view of the body and base of the valve showing a detail of the means for connecting them together;

Fig. 7 is a similar view showing an alternative mode of locating and connecting these parts;

Fig. 8 is a longitudinal section of anipple and drainage tube combination equivalent in some respects to that shown in Fig. 1;

Fig. 9 is a cross section of the latter combination taken on line 9-9 of Fig. 8;

is later described.) The residual or low water line in the valve casing is determined by the bottom of the passage through the drainage tube' 4' or the bottom of the bore l4, and is approximately at the location of the line AA' in Fig. 1. The height of this line, the relative heights of vent valve and valve seat, the weight of the combined float and valve unit, and the diameters of the float and valve casing are of such values that the float assemblage will rest on the support l2 and be just ready. to be lifted by the water at the level AA', and will be wholly afloat when the water rises to a slightly higher level Fig. 10 is a vertical section of the base portion of a so-called straight shank valve containing some of the novel principles and features of the type of valve shown in the preceding figures.

Like reference characters designate the same parts wherever they occur in all the figures.

The parts of the valve shown in Figs. 1-6 are a body or casing I in the upper end of which is secured a seat fitting or plug 2, a nipple or shank 3 secured .to the side of the casing, a siphonic drainage tube 4 mounted in the nipple, an orifice member 5, which is also a locking member, for controlling outflow of water and retaining the drainage tube, a base plate 9 secured in the bottom of the casing; a float I which is also a thermostatic member, and a vent valve pin 8 carried by the float. This valve is one of the angle type, as its attaching nipple is at one side projecting at right angles to the axis of the valve.

The plug 2 contains a vent port 9 opening through its outer end and a seat llbetween its ends. In its inner portion it contains an enlarged passage or chamber ll of enough larger diameter than the valve ,pin to permit outflow of air as rapidly as permitted by the area of the port. The

approximately designated by the line 3-3; and that the float will be raised enough to close the vent port when the water rises to a level approximating that indicated by the line 0-0, only slightly higher than the flotation level, and well below the top of the bore ll.

The difference between the levels A-A and B-B' is a factor of safety to make'certain that the float will be solidly supported and not adrift when the water is at its lowest level and allow for manufacturing variations in weights of different floats intended to be alike.

Thus, assuming conditions in which water enters and leaves the valve casing quietly, a small volume only of water, equal to the area of the float multiplied by the lift of the valve, plus, in some instances, a slight extra amount for the factor of safety referred to, need be drained in order to open the vent fully after being closedby flotation of the valve, and the depth of water to be drained .is much less than the diameter of the bore M. In valves performing the same duty as standard radiatorvent valves, such depth is in the order of 5%", and not more than This is the situation which would occur if the pressure within the system were the same as the atmospheric pressure. But in service the steam pressure is above the atmospheric and frequently surges of water rush into the valve,

compressing air in the casing and raising the water to a higher level, indicated in a general way by the line DD'. The internal volume of the casing, the volume of the float and the height of the top limit of the chamber l3 are so proaasasse Thus the principles of this valve include provisions whereby the minimum water level is at the bottom of the bore of the drainage tube or that in the connecting nipple, the water level of flotation is approximately at the low water line or slightly above it, the water level causing thev vent valve to close at a pressure equal to atmospheric is below the top of the bore through the nipple, and the highest water'level is near the top, and may be either somewhat above or below the top, of the, communication between the casing and the connecting nipple, such communication extending above the-top of the nipple bore. It is within my contemplation, however, and within the scope of the protection which I seek, to locate the water line at which the valve is closed by flotation at any height between the maximum and minimum levels. I

It will be noted-that the threaded part of the nipple, in which the bore is restricted by the standardized features 01' radiator construction previously referred to, is short; only so long as necessary to eflect a secure and rigid connection with the radiator. This length in the actual full-size valves is much less than one inch. .Hence the restricted-diameter bore is -too short for the formation of a water seal when filled with water; wherefore, after the water has risen to the high level indicated by the line D-D', and when the water in the radiator is at, or subsides to, a lower level, water is able to drip from the bore I4 and the adjacent portion I 3a of the nipple enlargecasing around the hole, while lugs 24a, or corners,

ment at the outer side of the locking member 5.

This leaves an opening il in the member it free for direct passage of air into the interior of the casing if the water level is below the top of- IS.

Or, if I! is sealed by water, air will bubble through the shallow water seal and rise above the water.

An important feature of the invention resides in the combination ofv the nipple, the drainage tube 4 and the orifice member or locking member 5. This member, in th form shown in Figs. 1, 4 and 5, is a plate, the diameter, or width and height, of which are such as to enable it to fit the nipple enlargement in the chamber l3; and a flange I6 is joined with the plate, extending laterally to space. the plate from the shoulder l1 between the nipple bore and the enlarged chamber. A circular hole I. .is formed in the plate of a diameter to fltthe drainage tube and at a distance from the periphery of the plate suitable to locate the drainage tube in the bottom of the bore H, as shown, when the plate is properly positioned. The tube is provided with external abutments i8 and 20 of external diam-T eter larger than the hole It, one of which is at the inner end of the tube and the other spaced apart therefrom. Cuts II (which may have no width or be slots of appreciable width) 55 are made in the plate extending from the edge of the hole It toward the circumference of the plate, forming spring leaves or tongues 22 which are adapted to yield and pass over the abutment i9, as shown by Fig. 5, and to spring back. to normal position in the space between the abutments, preventing dislodgment of the tube except by the use of force much greater than any forces encountered in service.

The abutments II and I! are here shown as I water line.

' the invention; for instance, as isolated nibs or protuberances like those shown at "a and 20a in Fig. 8.

The space between the 'abutments permits movement of the tube such that the same-valve may be used with different radiators in which there is considerable variation in the length of the threaded bore into which the nipple is screwed. The length. of the chamber i3 and the location of the locking plate 8 are made such that room is provided for movement of the abutment 20 between the locking platefand the shoulder ll, substantially equal to the movement of the abutment it between the locking plate and the valve float, without causing any interference with the latter. The locking plate is secured in position by a flange, or a seriesof tongues 23, formed by cutting or shearing the walls of the chamber inward from the open end thereof and pressing the displaced material against the rim facilitating drainage oi the valve casing when excessive accumulations of water occur, andpreventing spitting when the valve is vented under 1 II in this such circumstances. The opening member, located at a higher level than the outlet orifice or passage l8 when the valve is in operative position, allows flow of air into the casing, in a channel outside of and above the drainage tube 4, when the drainage tube .is discharging water. The flow area provided by this opening is augmented by so many and so much of the slots If as are above water, when such slots are made with appreciable width. The areas of such openings available for free flow of air vary with the height of the water lineD-D'. This water line is responsive to and varies with the radiator pressure; the higher the pressure, the higher the It is desired that the rate of water outflow should be substantially constant under all pressures. Consequently the inflow of air to the casing should be likewise constant under all pressures.

Variation in the tree area of the opening Il and the height of the water line are both similarly affected by the pressure in the radiator.

Thus with atmospheric pressure in the radiator,

. the water level in the valve 'is low and the free area of the opening II is a maximum. As the pressure increases, the water level rises and decreases the opening, thus checking the increased flow due to greater pressure. and making the rate of flow substantially or nearly constant.

The water may rise to excessive heights when, due to failure of the valve to close tightly from any cause, air escapes when water surges into the valve so that a back pressure of entrapped air considerable amount of water before the vent port can be fully opened, and for proper operation should be accomplished without so-called spitting, which may cause wetting of the adjacent room wall and dripping of water on the floor. Spitting is-caused by air bubblespassing at such high speed through the water that on breaking.

through the surface they form a spray which is carried throughthe vent port by the outwardly leaking air. The control of rate of air flow effected by the means above described prevents spitting.

When, after a surge and flooding of the valve casing, the water in the radiator subsides below the nipple, water is able to drip from the bore it. This enables air under the radiator pressure to pass through the opening and to rise into the casing whether or not the level therein is abnormally high. Drainage of the casing after every surge thus takw place freely and rapidly, and enables venting to be quickly resumed and conis not created. This necessitates drainage of a tinued until the next water surge, or until advent of steam causes the vent to be closed by thermostatic action.

In defining the meaning of the term orifice member" heretofore used in description of the member 5, the opening l8 may be considered as the water outlet orifice, and the opening l5 (plus other openings above the orifice I8 when present) as the air inlet orifice. The opening I8 is essentially an outflow orifice whether or not it is occupied or lined by a drainage tube. The utility of the orifice member is not dependent on combination with a nipple having an enlarged chamber adjacent 'to the casing, but is found in other situations as well. One such is that of a nipple or shank having a uniform bore of standard diameter from the interior of the casing to the outer end. Figs. 8 and 9 illustrate a form of the combination last referred to. The nipple or shank 3a there shown has no enlarged chamber at its inner end, and an orifice member or looking plate 511 of small enough diameter to enter the bore is secured therein by solder, staking, or other well known means. In substitution for the spring locking feature, the late is provided with a notch Ila in the rim of the opening for the drainage tube, and the tube is provided with isolated nibs or protuberances 19a and 20a of which at least the former is of a shape and dimensions enabling it to paw through such notch, but not through the hole when out of alinement with the notch. Both nibs are located out of line with the notch when the drainage tube is in the position which it normally assumes by gravity. But the tube can be inserted by rotating it until the nib lSa registers with the ntoch lfla. An opening or orifice I511 in the upper edge of this plate performs the same functions as the notch I! in the manner above described.

The same principles of low line of flotation and control of air flow may be embodied in vent valves of the straight shank type (i. e. valves of which the nipple is substantially in line with the axis) as well as those of the angle type. One such embodiment is shown in Fig. 10. Here the base 8a of the valve is formed with a centrally located downwardly contracting chamber |3b in its bottom, opening through a centrally located threaded nipple or shank 8b adapted to be screwed into the .upper side of a steam pipe, radiator section, or other part of a steam system; A drain tube 4a passes from the lower end of the chamber and is loosely supported in the orifice end thereof by a flaring enlargement or flange lb on its upper end. Theslip joint thus provided makes the drain valve self accommodating to pipes and steam passages of shallow depth. The lower end of the tube is beveled to permit free flow of water in case it should contact with the bottom of a pipe or radiator passage.

The bore a of the nipple 3b surrounding the drain tube is larger than the tube and substantially concentric with it, making an annular space. Air passages I 5b extend from the upper end of this annular space in the walls of the base 8a, opening into the chamber l3b at a height above the entrance to the drain tube. As many of these passages are provided as needed to make their combined cross sectional area as great as that of the drainage tube bore, or to have any desired ratio to the latter.

A spider or perforatedplatform 52a is secured over the chamber itb to support the float, and is made with sufficiently large and numerous openings to permit free flow of water. As to the upper part of the casing, the vent fitting, the vent closing valve and the construction and proportions of the float, the valve embodiment shown in Fig. 10 is or may be identical with that shown in occurs, they exercise a control over the air flow in conjunction with the head of .water above their upper openings. High pressure in the system compresses the air in the top of the valve casing and causes a higher water level than that caused by low pressure. This in turn causes a greater head on the air passages I 5b and retards .inward air flow so that the outflow of water is substantially or nearly the same under high pressure as it is under low pressure where the water head on the air passages is less.

In this form, as well as in the angle valve form, the float is so proportioned that it has a low line of flotation, whereby admission of only a small amount of water is necessary and sufllcient to cause operation of the valve by float action.

The valve contains novel details of construction having practical utility. The vent plug 2 is formed with a reduced diameter at its inner end which is passed through a hole in the casing and with a shoulder 25 which is brought to bear on the outside of an inturned flange 25 surrounding the hole in the casing. The intruding part is then staked in place by cutting grooves in its sides, so as. to form outturned tongues 21, as shown in Figs. 1 and 2, which are pressed against the. inner face of the flange, or by otherwiseforming one or more interior abutments, and solder is applied to the joint to make a secondary seal. This is one of the many means which may be employed in accordance with this invention and within the scope of my protection therefor, to effect a mechanical enlargement or abutment to hold the plug in place.

The base 6, likewise 6a, is made with a diameter suitable to enter the open end of the shell and is located at a prescribed distance from I a nipple projecting from the side of the casing The rim 29 extending from such stop means outside of the base is then turned over the margin ofthe latter to form a retaining flange, as shown. Such stop means may be a shoulder 30, Iormed by cutting away the interior of the shell, as

shown in Figs. 1, 6 and 10, or may be lugs or tongues 3! formed by cutting shallow slots in the casing wall, as shown by Fig. 7, or equivalent means known to those skilled-in the art. The

joint between the turned over rim 29 and the, base is sealed by solder.

The float, diaphragm and valve'stem assemblage may be of the same construction as herea nipple projecting from the side of the casing having an outer end of dimensions suitable to enter the standard vent valve tapping of such systems, a float in the casing, a valve carried having an outer end of dimensions suitable to I enter the standard vent valve tapping of such systems and an enlarged'inner end containing a chamber opening into the casing the highest point of which is above the top of the bore through the outer-end of the nipple, a float in the casing, a valve carried by the float and exby the float and extending upward toward the port, a drainage tube passing through the nipple, and a locking member secured in the nipple having a hole through which the drainage tube passes and the tube having external abutments located at opposite sides of said member, said abutments being spaced apart from one another and the locking member being spaced away from the float sufliciently to prevent contact or the inner end of the drainage tube with the float.

2. A vent valve for steam systems comprising a casing having a vent port in its upper portion, a nipple projecting from the side oi. the casing having an outer end ofdimensions suitable to enter the standard vent valve tapping of such systems and an enlarged inner end containing a chamber opening into the casing and the highest point of which is above the top of the bore through the outer end oi! the nipple, a float in the casing, a valve carried by the float and extending upward toward the port, a drainage tube passing through the nipple, and an orifice mem-' bersecured in the enlarged chamber having a hole through which the drainage'tube passes and the tube having external abutments located at opposite sides of said member, the oriflce memher having an air passageabove the drainage tube of an area such as to control the rate of ahflow through the drainage tube when water in the casing at a height above the nipple connection is draining iron: the casing.

3. a vent valve for steam systems comprising acasinghaving aventportinitnmperportion,

tending upward toward the port, a drainage tube passing through the nipple, and a locking plate secured in the enlarged chamber having a hole through which the drainage tube passes, the tube having external abutments located at opposite sides of said plate, said locking plate having cuts extending outward from the rim or the drainage tube hole therein forming resilient tongues adapted to be displaced by pressureoi the endmost abutment on the drainage tube in assembling the locking plate and tube, and to spring back into the space between the abutments on the tube when the endmost abutment has passed by.

4. A vent valve for "steam systems comprising a casing having a vent port in its upper portion and being free from inner partitions or the like in its interior, a nipple, projecting -from the side of the casing ofsuitable dimensions at its outer end to enter the standard vent valve tapping of such a system and having a single bore through said outer end of substantially the largestv practicable dimensions, and an enlarged chamber at the inner end or said bore into which said bore opens,- a drainage tube having a horizontal portion of smaller diameter than said bore occupying the lower portion of the bore, being horizontal all the way to its inner end, a float occupying said casing, a valve carried by said float arranged to close and open the vent port when the float is raised and lowered, the vertical movement or the valve for wholly opening the port being less than the diameter of said drainage tube, a float support in the casing located to sustain the float when in the position which causes full port opening oi the valve, the open interior of the casing enabling the minimum water level therein to be established at approximately the under side of the said horizontal portion or the drainage tube, and the nipple being so positioned that such minimum level is almost sufliclent to lift the, valve float from said support, the enlarged chamber at its entrance into the casing extending to a height approximating that or water forced into said casing by a surge after closing or said valve.

- WILLIAM K.

Images