Suction relief-valve.

Application filed April 23,1914. Serial No. 833,998.

To ΛΙ whom it may concern:

Be it known that I, James T. Atwood, a citizen of the United States, residing at Rockford, in the county of Winnebago and 5 State of Illinois, have invented certain new and useful Improvements in Suction Relief. Valves, of which the following is. a. specification.

This invention relates to the general art 10 of relief-valves and more particularly to those employed in vacuum cleaning systems or other apparatus where suction is used.

In vacuum cleaning apparatus it is customary to provide an exhauster operable by 15 suitable power driven means for producing vacuum in a receptacle to which dust and dirt laden air is drawn by the vacuum through tubes from the points of cleaning, the dust and dirt in whole or in part being 20 retained in the receptacle and the air with dust, if any, being drawn to the vacuum producer and discharged therefrom. When the cleaning operation is interrupted the air inlet to said receptacle is shut off thereby 25 causing a strong vacuum to be developed in the receptacle, which imposes an excessive and undesirable load upon the vacuum producer and driving means. With the view of obviating this difficulty it has been cus80 tomary to provide the vacuum receptacle or the vacuum line with an ordinary relief valve adapted when a predetermined vacuum is attained to automatically open and permit inflow of air thereby relieving the 35 vacuum producing mechanism of unnecessary burden and the driving mechanism of undue strains.

One of the primary objects of my invention is to provide a suction operated relief40 valve which will automatically open and permit intake of air into a vacuum cleaner chamber when a predetermined maximum suction has been developed, and which having been opened will be retained in open po45 sition by a considerably lesser suction force than is required to initially open it, thus materially reducing the strain on the vacuum producer and diminishing the power required to drive it.

Another object is the provision of a suction operated valve which will perform the desired functions with accuracy and precision and which will be simple in construction and cheap to manufacture.

A valve of this character applied to a vacuum system as has been described, auto matically admits air to the vacuum receptacle or vacuum line when a vacuum of a predetermined number of inches has been created therein, and effects a rapid reduction 60 in the vacuum to a predetermined amount thereby materially reducing the load on the vacuum producing mechanism.

In the accompanying drawings, Figure 1 is a view in elevation of part of a vacuum 65 cleaning system embodying my invention. Eig. 2 is ;an enlarged vertical sectional view through the relief-valve, and Figs. 3, 4, and 5 ..are. transverse sectional views through the relief-valve taken on the lines 3—3, 4—4, 70 and 5—-5 respectively of Fig. 2.

By reference to the drawings it will be observed that a vacuum producer 6. adapted to be driven by suitable power means, is connected, through the pipe 7 with a receptacle 75 or chamber 8 in which vacuum is maintained by the producer and to which dust and dirt laden air is drawn through the suction pipe 8' from the usual nozzle or cleaning tool (not shown), the dust and dirt in whole or 80 in part being·separated from the air and retained-in the receptacle while the air with dust, if any, is dra wn therefrom to the vacuum producer and discharged to the outer atmosphere and preferably to a sewer. The 85 relief-valve embodying my invention is preferably threaded, into the top of the receptacle and is adapted to automatically control the amount of vacuum created therein by the producer. 90

The relief-valve as shown comprises-a casing 9 screw-threaded into the top of the receptacle 8, and providing a circular chamber 10 opening into the receptacle. The transverse Avail forming the top of the. cham- 95 ber is provided with a reduced opening 11 through which communication is established between the chamber 10 and the atmosphere, said opening 11 being shaped to provide a tapered or beveled valve-seat at its under 100 side. A valve-disk 12 carried by the stem 13 cooperates with the valve-seat to close the opening 11, said stem being slidably guided in the sleeve 14 formed integral with the casing 9. A spiral compression spring 15 105 normally maintains the valve in closed position, the tension of this spring being adjustable by a lock-nut 15' to adjust the valve to a predetermined vacuum under the influence of which it will open. The valve-disk is 110 provided beneath the seat with an annular flange or supplemental disk 16 disposed con1,156,873 centrically within the chamber 10 and presenting a surface of greater area than the top of the valve-disk, and of less area than the cross-sectional area of said chamber 10, 5 the peripheral edges of the flange beingspaced from the adjacent Avails of the chamber to provide a passage 17 surrounding the flange.

When the valve is closed the upper face 10 of the disk or flange 16 is spaced from the top wall of the chamber 10 and when the valve is open the disk 16 will be disposed beneath the lower edges of the side Avails of the chamber. The length of chamber 10 15 is such that with the disk 16 held in open position the valve 12 will give opening 11 a full area opening.

Assuming for purposes of illustration, that the maximum vacuum which it is de20 sirable to induce is 8 inches of mercury when the system is in use, it will be evident that if the use of air is discontinued by shutting off the suction pipe, a vacuum in excess of the desired maximum will be produced in 25 the receptacle by the producer, which will cause the latter to operate under an excessively heavy load unless this excess is relieved by a relief-valve or other similar device. If an ordinary relief-valve set to open 30 under 8 inches of vacuum is employed, the valve will open when the desired maximum vacuum is reached but it will close again when the vacuum falls slightly beloAv the maximum, with the result that a. high 35 vacuum approaching the maximum will be maintained as long as the machine runs v/ith the suction closed or nearly closed.

With the relief valve set forth in this invention when the use of air is discontinued in 40 Avhole or in part the vacuum may rise to the desired 8 inches and at this point acting on the area of valve 12 it overcomes the resistance of the spring 15 and admits air of atmospheric pressure into chamber 10 above 45 disk 16. The vacuum in the tank noAv acts upon the larger area of disk 16 and alloAvs air to enter more freely so that the vacuum drops materially to a predetermined amount depending upon the relative areas of 12 and 50 16 to about 4 inches.' Thus the strain on the producer and tile power required are materially lessened by the use of this valve. In order that the valve will close readily when more air again enters the system through 55 the cleaning hose, the area of passage 17 must be adjusted approximately for the air capacity of the vacuum cleaner system upon which it is used. This area 17 is slightly smaller than the area between the lower edge 60 of chamber 10 and the upper edge of disk 16 when all the air is entering through the

Copies of this patent may he obtained for five cents valve. When a very small amount of air enters the system elsewhere the area between these tAvo edges is reduced accordingly but the valve remains open so long as this area 65 is greater than area 17. Only a comparatively small amount of the total air needs to enter elsewhere such as through the cleaninghose to reduce the area between these tAvo edges down to the size of area 17 at which 70 point the pressure of the spring overcomes the action of the vacuum on disk 16 and the valve closes. Under ordinary conditions the closing will take place when the vacuum has been reduced to about 4 inches. It will thus 75 be apparent that the valve cannot remain in an approximate balance so as to flutter between open and closed positions.

While I have described an illustrative example of relative suction forces for the pur- 80 pose of explaining the use of my improA^ed suction valve, it is obvious that the proportions and sizes of the valve surfaces, the passages, and spring may be varied to effect different ranges of maximum and minimum 851 suctions controllable by the valve.