US3311302A

US3311302A - Two-way damper with adjustable sensitivity

Info

Publication number: US3311302A
Authority: US
Inventors: Claude O Merckle
Original assignee: Danzer Metal Works Co Inc
Current assignee: Danzer Metal Works Co Inc
Priority date: 1965-03-01
Filing date: 1965-03-01
Publication date: 1967-03-28
Anticipated expiration: 1984-03-28

Description

March 28, 1967 c. o. MERCKLE 3,311,302

TWOWAY DAMPER WITH ADJUSTABLE SENSITIVITY Filed March 1, 1965 INVENTOR CLAUDE 0. MERCKLE ATTORNEY United States Patent 3,311,302 TWO-WAY DAMPER WITH ADJUSTABLE SENSITIVITY Claude O. iderckle, Hagerstown, Md., assignor to The Danzer Metal Works Co., Inc., Hagerstown, Md., a

corporation of Maryland Filed Mar. 1, 1965, Ser. No. 436,186 4 Claims. (Cl. 236-45) This invention relates broadly to dampers or draft regulators, and more particularly to a two-way active damper for use in vertical flues or pipes.

An important object of the invention is to provide a twoway damper for vertical ducts which may be delicately balanced to a horizontal or closed postion within the duct and adapted to tilt or open in either direction under the infiuence of barometric pressure changes, drafts, variable weather conditions and the like.

Another important object of the invention is to provide a pivoted damper blade or gate which is held in the normally closed position by variable spring tension, and including novel, compact and simplified means for adjusting the spring tension to thereby regulate the opening and closing of the gate in response to various pressures on either side thereof or in either direction.

Still another object is to provide a two-way damper which is rugged in construction and therefore durable, economical to manufacture, and reliable and efficient in operation.

ther objects and advantages of the invention will become apparent during the course of the following detailed description.

In the accompanying drawings forming a part of this application and in which like numerals are employed to designate like parts throughout the same,

FIGURE 1 is a perspective view of a two-way damper embodying the invention, partly broken away;

FIGURE 2 is another perspective view showing the lower side of the device, partly broken away; and

FIGURE 3 is a central transverse vertical section taken on line 3-3 of FIGURE 1.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the invention, the numberal designates a cylindrical sleeve constituting the body portion of the damper and which sleeve may constitute an integral section of an upright pipe, flue or ventilating duct or may be a separately formed member for connection in the pipe, flue or duct.

Rockably mounted Within the bore of the sleeve 10 in relatively close fitting engagement therewith is a damper blade or plate assembly 11 consisting of a generally fiat circular damper blade 12 and a supporting rocker shaft 13. As shown in the drawings, the rocker shaft 13 is offset to one side of the center of the damper blade so that the latter will tilt in either direction upon the offset axis of the rocker shaft in response to differences in pressure upon either side thereof. The offset arrangement of the rocker shaft 13 provides sections of unequal area on the blade 12 so that it will respond in either direction to pressure.

In order to accommodate the shaft 13, the damper blade 12 is provided with a generally U-shaped rib or corrugation 14 extending entirely across the same generally diametrically although offset from the center of the blade, as stated. The rocker shaft 13 lies within the confines of this rib 14 and is secured rigidly therein by pinning, soldering, welding or by any other suitable means. The uncovered side of the shaft 13 is substantially flush with the adjacent fiat side of the damper blade, as shown in FIGURE 3. The blade and rocker shaft thus constitute a permanently assembled substantially rigid unit for operation within the sleeve 10.

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End portions 15 of rocker shaft 13 project beyond the opposite sides of the damper blade and are held rotatably within suitable bearings 16, anchored within openings in the wall or sleeve 10. The bearings 16 are preferably Oilite bearings or other conventional low friction bearings to render the damper blade assembly free tilting with a minimum of friction.

In order to compensate for the natural unbalance of the damper blade on the axis of the offset rocker shaft, an adjustable counterweight 17 is provided upon one side of the blade and on the portion thereof which is the smallest or lightest in weight. A lead weight or the like may be employed and the weight is slotted as indicated at 18 to facilitate adjusting the weight toward and away from the axis of the rocker shaft 13. A screw or bolt 19 may be employed to anchor the weight 17 directly to the damper blade adjustably, as shown. By this means, the entire damper blade assembly may be delicately balanced upon the offset axis of the shaft 13 so that the assembly will remain in the level or closed position indicated in FIGURE 3 is there are no unbalancing pressures or forces acting upon the same.

Adjustable resilient means are provided for regulating the opening of the damper in either direction in response to pressures thereon and for returning the damper automatically to its normally closed or draft blocking position shown in the drawings with the desired degree of firmness. This means comprises a relatively small fiat adjustable slide plate 20 on one side of the blade 12 and having an elongated adjusting slot 21 formed therethrough and extending at right angles to the axis of the rocker shaft 13. The slide plate 2% is adjustably anchored to the damper blade by means of a screw 22, whereby the slide plate may be shifted across the shaft 13 in either direction and firmly locked in any selected adjusted position. A retractile coil spring 23 extends longitudinally beyond one end of the plate 20 and has one end loop thereof anchored to a small opening 24 in the adjacent end of the slide plate. The remote end of the spring is suitably anchored as at 25 to the side wall of damper sleeve or body portion 10. The spring extends radially of the damper blade and lies in a common plane substantially with the damper blade and the slide plate 20, thus rendering the entire assembly very compact and uncluttered. In order to permit the required relative movement between the spring and the damper blade, the latter has a radial slot formed therethrough adjacent to the spring and extending from a point near the shaft 13 entirely through the peripheral edge of the damper blade. The slot 26 is adequately wide to permit the passage of the small spring therethrough without interference whenever the damper blade tilts upwardly or downwardly from the normal neutral or level position shown in FIGURE 3.

The broken lines and the arrows in FIGURE 3 illustrate diagrammatically the ability of the damper to open in either direction by tilting in a vertical duct or pipe. The spring 23 yields to allow tilting or opening of the damper in either direction and constantly urges the damper to return to the normal closed or neutral position. The sensitivity of the damper may be regulated through wide limits by simply adjusting the tension of the damper spring by shifting the slide plate longitudinally of its slot 21 and at right angles to the rocker shaft 13. By this means, the damper blade can be rendered quite stiff so that a relatively strong draft or change in pressure will be required to cause any appreciable opening or tilting. On the other hand, the damper blade may be rendered extremely soft-acting or sensitive to slight variations in draft or pressure on either side thereof by adjusting the tension of the spring. Quite obviously. the strength of the spring is increased by shifting the slide plate 20 radially inwardly and the strength of the spring decreased by moving the adjusting slide plate radially outwardly. In any adjusted condition, the force of the spring will serve to hold the damper blade in the closed or neutral position as depicted in the drawings. It is believed that the advantages of the construction in providing a doubleacting damper with simiplicity and ease of adjustment will be apparent to anyone skilled in the art,

It is to be understood that the form of the invention herewith shown and described is to be taken as 'a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

The invention having been described, what is claimed 1. A twow'ay active damper comprising a damper blade adapted to be mounted in an upright sleeve section, a rocker shaft pivotally supporting the damper blade in the bore of the sleeve section for tilting movement on an axis which is offset from the geometrical center of the damper blade, adjustable counterbalancing means on the damper blade to permit the damper blade to assume a level bore closing position, said damper blade having a radial slot formed therethrough, an adjusting slide plate on one face of the damper blade and having an adjusting slot lengthwise of the first-named slot and at right angles to said axis, means to clamp the slide plate in a selected adjusted position upon the damper blade, and a retractile spring adjacent the first-named slot and adapted to pass through the slot whenever the damper blade tilts in either direction upon said axis, said spring having one end secured to said slide plate and its opposite end secured to the sleeve section, said spring, damper blade and slide plate all lying substantially, in a common plane when the damper blade is in the level bore closing position.

2. A two-way damper comprising a damper sleeve, a damper blade tiltably mounted within said sleeve upon a rocker shaft whose axis is offset laterally from the center of the damper blade, adjustable counterbalancing means on the damper blade to allow leveling thereof within the sleeve to substantially close the bore of the sleeve, a retractile spring, means to anchor one end of said spring to the sleeve, an adjustable slide plate on the damper blade and secured to the other end of the spring and operable to regulate the tension of the spring, the spring tending to hold the damper blade in said level position but yielding to permit tilting of the damper blade in opposite directions from said level position, said damper blade having a clearance opening through which said spring may pass during said tilting of the damper blade in opposite directions.

3. A two-way draft damper for use in a vertical duct comprising a damper sleeve for connection in said vertical duct, a damper blade within said sleeve adapted to substantially close the bore of said sleeve when in a level position, a rocker sh'aft secured to and carrying the damper blade and being offset from the geometrical center of the damper blade and sleeve, a pair of aligned bearings on the sleeve rota-tably supporting the ends of the rocker shaft, an adjustable counterbalaneing means on the damper blade to facilitate leveling the damper blade, an adjusting element on the damper blade shiftable generally radially thereon "at right angles to the axis of the rocker shaft, a spring connected with said element and also connected with said sleeve and being tensioned by tilting of the damper blade in either direction away from said level position and thereby tending to return the damper blade to the level position, the damper blade having a through passage to permit relative movement of the damper blade and spring during said tilting.

4. A two-way active damper for a vertical duct comprising a damper sleeve for connection in the duct, a damper blade tiltably mounted within the bore of the damper sleeve and adapted to substantially close the bore when in a level position substantially at right angles to the axis of the damper sleeve, a retractile spring normally lying substantially in the plane of the damper blade when said blade is level, said spring extending substantially radially of the blade, the damper blade having a radial clearance slot through which the spring may pass without interfering with the damper blade when the damper blade tilts in either direction, means anchoring the outer end of the spring to said damper sleeve, 'and means forming a radially adjustable connection between the inner end of the spring and damper blade whereby the tension of the of the spring may be regulated.

References Cited by the Examiner UNITED STATES PATENTS 1,301,455 4/1919 Kiessig 137527 2,073,386 3/1937 Cunningham 236-45 2,194,691 3/1940 Cornell 236-45 X 2.282,125 5/1942 Firehammer 236-43 WILLIAM J. WYE, Primary Examiner.

ALDEN D. STEWART. Examiner.

Claims

1. A TWO-WAY ACTIVE DAMPER COMPRISING A DAMPER BLADE ADAPTED TO BE MOUNTED IN AN UPRIGHT SLEEVE SECTION, A ROCKER SHAFT PIVOTALLY SUPPORTING THE DAMPER BLADE IN THE BORE OF THE SLEEVE SECTION FOR TILTING MOVEMENT ON AN AXIS WHICH IS OFFSET FROM THE GEOMETRICAL CENTER OF THE DAMPER BLADE, ADJUSTABLE COUNTERBALANCING MEANS ON THE DAMPER BLADE TO PERMIT THE DAMPER BLADE TO ASSUME A LEVEL BORE CLOSING POSITION, SAID DAMPER BLADE HAVING A RADIAL SLOT FORMED THERETHROUGH, AN ADJUSTING SLIDE PLATE ON ONE FACE OF THE DAMPER BLADE AND HAVING AN ADJUSTING SLOT LENGTHWISE OF THE FIRST-NAMED SLOT AND AT RIGHT ANGLES TO SAID AXIS, MEANS TO CLAMP THE SLIDE PLATE IN A SELECTED ADJUSTED POSITION UPON THE DAMPER BLADE, AND A RETRACTILE SPRING ADJACENT THE FIRST-NAMED SLOT AND ADAPTED TO PASS THROUGH THE SLOT WHENEVER THE DAMPER BLADE TILTS IN EITHER DIRECTION UPON SAID AXIS, SAID SPRING HAVING ONE END SECURED TO SAID SLIDE PLATE AND ITS OPPOSITE END SECURED TO THE SLEEVE SECTION, SAID SPRING, DAMPER BLADE AND SLIDE PLATE ALL LYING SUBSTANTIALLY, IN A COMMON PLANE WHEN THE DAMPER BLADE IS IN THE LEVEL BORE CLOSING POSITION.