US643319A - Thermally-actuated mechanism. - Google Patents

Description

No. 643,3l9. Patented Feb. l3, I900;

' J. H. BULLARD.

THERMALLY ACTUATED MECHANISM.

(Application filed May 3. 1899.)

(N0 Moda'l.)

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JAMES H. BULLARD, OF SPRINGFIELD, MASSACHUSETTS.

TH ERMALLY-ACTUATED M'ECHANIS lVl SPECIFICATION forming part of Letters Patent No. 643,319, dated February 13, 1900.

Application filed May 3, 1899. Serial No. 715,471. (No model.)

To wZZ whom it may concern:

Be it known that 1, JAMES H. BULLARD, a citizen of the United States of America, residing at Springfield, in the county of Hampden and State of Massachusetts, have invented new and useful Improvements in Thermally- Actuated Mechanism, of which the following is a specification.

This invention relates to thermally-actuated mechanisms for the control of valves and for analogous uses wherein fluctuations in the temperature to which said mechanisms are subjected will operate to setin motion through the action of said mechanisms devices whose operation is necessitated by said variation in temperature.

The objects of this invention are to provide for the quickest possible operation of the mechanism upon a change of temperature and to provide an unchanging point of support for the expanding member of the thermally-actuated mechanism, whereby expansive movements of the base on which said mechanism is supported will not affect the relation of one part of said mechanism to another, to the end that the operation of said mechanism will be of a uniform character under Whatever con ditions of temperature said base may be subjected to.

A further object of the invention lies in the adaptation of the thermally-actuated mechanism to a valve, whereby excessive expansive movements of the mechanism will be provided for beyond the degree of movement necessary to operate the valve without subjecting the parts to any strain.

The invention consists in the construction described in the following specification and pointed out in the claims.

In the drawings forming part of this specification, Figure 1 shows in elevation the invention forming the subject of this application operatively connected with a valve. Fig. 2 is a cross-section on line 2 2, Fig. 1. Fig. 3 is a view of one end of a steam-boiler and shows the adaptation of the thermally-actuated mechanism to a valve in the steam-pipe of a feed-pump. Fig. 4 shows in section, on a somewhat-enlarged scale, a disk-valve adapted to be operated by the expansion devices shown in Fig. 1. Figs. 5 and 6 are respectively a top plan view of said valve and a transverse section thereof on line 6 6, Fig. 4. Fig. '7 illustrates a piston-valve adapted to be operated by the expansion device shown in Fig. 1.

It frequently happens in certain construetions wherein automatic boilerfeed is required that lack of space necessitates the location of the thermally-actuated mechanism, which operates to set in motion devices for feeding water to a boiler, in close proximity to said boiler, where the temperature is greatly above the normal and where by reason of said high temperature a metal base for supporting said thermally-actuated mechanism is rendered necessary. In such cases the working of a thermally-actuated mechanism is irregular and unsatisfactory by reason of the change of position of its component parts one rela tive to the other, due to the expansion of the base on which it is supported.

Even under most favorable conditions the operative movements of devices actuated by changes of temperature are of very limited range, and hence a loss of a part thereof from any cause frequently necessitates the abandonment of their use and the substitution of a device much less efficient.

This invention operates to apply effectively all of the movement resulting from the change in endwise dimension of the expansible memberor members of a thermally-actuated mechanism whatever may be the change in dimension of the base on which said mechanism is supported, all as hereinafter described. Furthermore, in thermally-actuated mechanisms for controlling the supply of feed-Water to a boiler wherein only the variations between the temperature of the water therein and the steam generated therefrom impart movement to said mechanisms the operation of the latter is very slow by reason of the slight difference existing between the temperature of the water and steam, and this is especially true where the steam-pressure is. low. This invention overcomes this objection by providing means for cooling the water from the boiler before it comes into contact with said thermally-actuated mechanism, all as fully described farther on.

The type of the thermally-actuated mechanism shown in this application is that one in which a tubular member is located outside of a boiler andin the plane of the normal water-level thereof and which member is occupied either by water or steam, according as the water-level rises or falls, said member being connected by pipes with both the steamspaee and water-space of the boiler. In carrying out this invention said expansible memher is made of substantially U shape, one of the tubular arms 2 thereof being located substantially on the normal water-level of the boiler and the other arm 3 parallel therewith below said water-level, and these two arms are connected by a short vertical pipe 4. The end of the arm 3 is connected by a pipe 5 to the water-space of the boiler, and the end of the arm 2 by a pipe t with the steam-space thereof. Practically the tubular arm 2 is the expansible memberand is supported on a base comprising the plate 7 and an encircling frame 8 therefor of the same thickness, said plate being suspended by one end to the end of said frame and being free from contact therewith at any other point. Said base is supported at one end by the same screws 8 which secure the plate to the frame. As shown in Fig. 2, the sides of the plate 7 and frame 8 are in the same plane. The said plate and frame, which together constitute the support for the expansible member of the device, are made of two metals having different degrees of expansion at the same temperature. In this case the plate 7 is made of steel and the frame 8 of aluminium. The expansion of aluminium as compared with that of steel is as two to one. Near the free end of the plate 7 a perforation 7 is made therethrough, and a pair of links 10 is pivoted to the frame 8 substantially over said perforation at 12, and at the opposite ends of said links said expansible member is pivotally supported at 13 by an arm extending from one end of the tubular arm 2, and the expansion of the frame 8 and plate 7 being as two to one the links are pivoted to the latter at 14 midway between the points 12 and 13. If the plate and frame were made of metals relatively expansible in the ratio of three to one, the pivotal point 14 of the links on said plate would then be located at a point one-third of the distance between the points 12 and 13. Thus the pivotal point of the links between the points 12 and 13 thereof must always bear the same ratio to the distance between said points as the ratio existing between the different degrees of expansion of the plate 7 and its frame 8. The point 13 by this construction becomes the fixed abutment against which the expansive movement of the arm 2 takes place, and it is readily apparent that whatever may be the expansion of the base on which said arm is supported the point 13 will remain unchanged relative to the point of support of said base on the screws 8. For instance, let it be supposed that the plate 7 would expand sufliciently to produce an elongation thereof of one-twentieth of an inch. The same degree of heat would expand the frame 8 two-twentieths, and the contraction thereof would be in the same proportion, and

the result would be that the links 10 would swing on the point 13 as a pivot, and the points 12 and 14 always would remain in line with said point. The opposite end of the arm2 is provided with a short arm in which is a pin 15, which engages a swinging lever 16, pivoted at 17 on the plate 7 so near its point of support that the expansion of said plate will not affect the operation of the mechanism. Said swinging lever by its upper end is connected by a rod 18 with a crank 19 on the end of the stem 20 of a valve 21, located in a steampipe 22, representing, for instance, the pipe wherebyasteam-pump is operated to supply water to a steam-boiler.

Fig. 3 represents the arrangement of the thermally-actuating mechanism when used in connection with a steam-boiler and waterfeeding devices therefor, 23 representing the boiler, and 24 the steam-pump.

To insure the quickest action of the thermally-actuated mechanism possible, it is desirable that the extremes of temperature actuating said mechanism shall be as widely separated as possible, and to that end the arm 3 of the expanding member is jacketed by a pipe 25, whose ends are sealed to the surface of said arm, and an inlet-pipe 26 and an outlet-pipe 27 are provided for said jacket. The pipe 26 is connected with the delivery end of the pump 24, and the Water from the latter passes through said jacket 25 and out through the pipe 27 to the boiler, and, if desired, through a feed-water heater (indicated by 28) located in said pipe 27. As the water in the boiler rises it will rise also in the pipe 5 and, entering the arm 3 of the expansible member, pass up through the pipe 4 into the arm 2 and be cooled by the colder water in the jacket 25 as it passes through said arm 3, thus providing means for creating a much wider difference between the opposite temperatures, which alternately expand and contract the expansible member of the mechanism, than if the water from the boiler were permitted to come in contact with said member without being cooled.

In thermally actuated mechanisms employed for the purposes herein described great difficulty has been encountered in providing suitable valves adapted for use therewith, and generally the ordinary globe-valve has been used, which is opened and closed by the movement of a valve-disk toward and away from a tapered annular valve-seat, and various means have been resorted to to provide for any movement of the expansible member which operates said disk after the latter has come to a bearing against its seat, whereby the valve-operating mechanism would be relieved from undue strain. To overcome this objection, the use of avalve constructed like those shown in Figs. 4 to 7 has been found most desirable. The valve shown in Figs. 4 to 6 is the preferred construction. form of valve the diaphragm 29, dividing the valve-body between the inlet and outlet ends In this thereof, is provided with a series of transverse apertures 30 and the valve-disk 31 on the stem with similar perforations 32 therethrough, adapted to register with said apertures when the stem is rotated by the expansive movements of the arm 2. Upon the contraction of said arm said perforation will lie, as shown in Fig. 6, between the apertures 30, and the pressure of steam against said disk will forcibly seat the disk against said diaphragm and seal said apertures. Another form of valve which may be used is shown in Fig. 7. This valve is of the so-called piston type and consists of a hollow head 33, attached directly to the rod 18, the closed end of said head lying within the wall of the diaphragm 33 when the valve is closed, and when opened by the movement of said rod 18 slots 34 in the wall of said head and communicating with the interior thereof will project beyond the face of the diaphragm on the inlet side and allow steam to pass through one end of said slots and into said head and out of the other-end of the slots into the valvebodyon the outlet side of said diaphragm. If desired, the peculiar characteristics of the base construction and the links for support ing the expansible member may be advantageously availed of for compounding the expansive movements of the base and said expansible member, whereby a wider range of movement of the swinging lever 16 may be attained. This may be accomplished by merely locating the point of connection 14 between the link 10 and the plate 7 at such a point that the unequal expansion of the two parts of the base will operate to swing the lower end of the links 10 toward the fixed end of the base, and thereby cause a swinging movement to be imparted to the lever 16 in addition to the movement it has imparted to it by expansion. In the construction as described this result would be attained by raising the point 14 to any degree above its present location.

Having thus described my invention, what I claim, and desire to secure by Letters Patent of the United States, is-

1. In a thermally-actuated mechanism, an expansible member and a base therefor consistin g of two metals having different degrees of expansion at the same temperature, means of support for one end of said expansible member on said base whereby an immovable abutment for said expanding member is provided independent of the expansive movements of said base, a device operated by said expansible member, as a valve, and means of connection between the free end of said member and said device, substantially as described.

2. In a thermally-actuated mechanism co1nprising an expansible member, and a device, as a valve, operated thereby, a base for said expansible member comprising two parts having different degrees of expansion at the same temperature, means for supporting one end of each of said parts immovably; a support for one end of said expansible member pivotally connected at one of its extremities with one end of said expansible member, the op posite extremity of said support being pivotally connected to the free end of one part of said base, and a pivotal connection between the ends of said support to the free end of the other part of said base, substantially as described.

- 3. In a thermally-actuated mechanism, a base therefor composed of two materials separatel y movable by expansion and having different degrees of expansion at the same temperature, an expansible member, a link uniting said two materials and supporting one end of said expansible member whereby the expansible movement of one of said materials constituting said base will be neutralized by the expansion in a different degree of the other of said materials, and the point of support on said link for said expansible member thus caused to remain stationary under changes of temperature to which the said base may be subjected, substantially as described.

4. In a thermallyactuated mechanism, a suitable base, a tubular expansible member supported on said base and having a tubular extension locatedin a lower plane, said member being adapted to receive fluids havingdifferent temperatures; a jacket surrounding the tubular extension of said member, and means for forcing water through said jacket, whereby the temperature of one of said fluids will be reduced, substantially as described.

5. In a thermally-actuated mechanism, a water-supply pipe, a valve in said pipe, acompensating base, a tubular expansible member supported by one end on said base and pr0- vided with a tubular extension in a lower plane, a connection between the opposite end of said member and said valve, a jacket sur* rounding said extension having an outlet therein, and a pipe connecting said jacket with said supply-pipe, whereby the actuation of said valve by said expansible member will cause water to pass through said jacket and in contact with said extension, substantially as described.

6. In combination with a boiler, mechanism for feeding water thereto, a steam-pipe from said boiler to said mechanism, a valve in said pipe, a tubular expansible member having a tubular extension in a lower plane and adapted to operate by the alternate contact of steam and water from the boiler, a jacket surrounding said extension, and pipes leading therefrom to said water-feeding mechanism and said-boiler, whereby water supplied to said boiler must pass through said jacket for reducing the temperature of a part of said expansible member, substantially as described.

7. A compensating base for supporting the expansible member of a thermally-actuated mechanism, which base consists of two metal plates having difierent degrees of expansion at the same temperature means for support-- ing said plates immovably whereby one end of each will be free to expand independently, a link, one end of which pivotally engages one of said plates and the opposite end of which forms a pivotal support for said expansible member; a point of connection between said link and the other of said plates and having the same relation to the distance between the ends of said link as that which exists in the ratio of the expansive quality of one of said plates relative to the other, substantially as described.

8. In combination, a boiler, a Water-feeding device therefor, a thermally-actuated mechanism for controlling said Water-feeding device, comprising a tubular expansible member having a tubular extension in the lower plane, a jacket inclosing said tubular extension and a pipe connection from said Waterfeeding device to said jacket, and from the latter to the boiler, whereby Water passing from said feeding device to said boiler will come in contact during said passage with a part of said thermally-actuated mechanism to lower the temperature of the latter, substantially as described.

9. In a thermally-actuated device comprising a tubular expansible member having a tubular extension in the lower plane and operated by the alternate contact of steam and water, a jacket surrounding a part of said device and means for circulating a cooling medium through said jacket for reducing the temperature of that part of the thermallyactuated device therein, substantially as described.

JAMES H. BULLARD. \Vitnesses:

H. A. CHAPIN, K. I. OLnMoNs.

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