Double glazed window

Dec. 15, 1936. f. gelstharp et al 2,064,530

DOUBLE GLAZED WINDOW

<img file="US2064530A_D0001.tif" />

<img file="US2064530A_D0002.tif" />

Patented Dec. 15, 1936

2,064,530

UNITED STATES PATENT OFFICE

2,064,530

DOUBLE GLAZED WINDOW

Frederick Gelstharp and Joseph Carl Parkinson, Tarentum, Pa., assignors to Pittsburgh Plate Glass Company, a corporation of Pennsylvania

Application March 21, 1934, Serial No. 716,636

Claims. (CI. 20—56.5)

The invention relates to a double glazed window construction for use in buildings and refrigerator case structures. It has for its principal objects, (1) the provision of improved means for hermeti5 cally sealing off the space between the glass sheets from the outer atmosphere; (2) the provision of a construction applicable to ordinary wood sash which permits the ready removal of the sheets for cleaning or replacement; and (3) the pro10 vision of a construction having improved means permitting the filling of the space between the glass sheets with dry air in order to avoid condensation and prevent or limit the formation of an alkaline clouding film on the inner surfaces 15 of the sheets. Certain embodiments of the invention are illustrated in the accompanying drawing, wherein:

Figure 1 is a front elevation of the construction. Fig. 2 is a section on the line II—II of 20 ^pig·. ^Fig· ³ is a detail perspective view of the sealing member. Fig. 4 is a detail view partially in section of the sealing member. And Figs. 5 and 6 are sectional views illustrating modifications.

Referring to the construction of Figs. 1 to 4, ί is a sash which is in this instance of wood; 2, 2 are sheets of glass; 3 is a packing or sealing member placed between the glass sheets; and 4 is a clamping plate which engages the outer face 30 of one of the glass sheets, such plate being held in place by the screws 5 and being of wood in the present instance. The sash I is provided with a seating abutment or shoulder 6 whose outer portions act as seating ledges for the edges 35 of the glass sheets and is also provided with a shoulder 7 in opposition to the outer face of one of the glass sheets 2.

The sealing member is preferably in the form of an integral rectangular frame of metal which 4q fits snugly into the sash and is provided on its opposite faces with the rubber sealing strips 6 and 9 which are preferably cemented to the memtier 3. When the parts are positioned, as indicated in Figs. 1 and 2, and the plate 4 is clamped in 45 position by means of the screws 5, the rubber strips 8 and 9 are placed under compression so that they are thinned and widened, as indicated in Fig. S, and form a very secure seal for the space between the two glass sheets.

In order to provide for the application of dry air to the space between the sheets 2, 2, the tubes 10, 10 are provided, such tubes extending through the sash and through the member 3, as indicated in Figs. 2 and 4, the inner ends of the tubes being screwed into the member 3 so that they are se curely held in position and act as an anchoring means for the member 3. In order to prevent condensation, and efflorescence upon the inner faces of the glass sheets, the space between the two sheets is supplied with dry air when the con- 5 struction is installed. This may be done by any suitable means whereby dry air is forced through one of the tubes 10, and is evacuated through the other tubes until the air which fills the space between the glass sheets is completely dry. The jo outer ends of the tubes are then sealed by means of the screws Η, 11 which are threaded into the tubes.

Fig. 5 illustrates a modification in which the sash 12 is of metal instead of wood and in which 15 two clamping plates 13, 13 are employed, such plates being held in place by means of the machine screws 14. In this instance, the transparent plates IS, 15 are of safety glass; that is, each plate consists of a pair of sheets of thin ₂₀plate glass with an interposed sheet of reinforcing material to Which the glass sheets are cemented. In this construction, the sealing member 16 is integral with the sash instead of being separate therefrom and is provided on its sides .,with sealing strips of rubber, similar to the strips 8 and 9 heretofore described.

Fig. 6 illustrates another modification in which the sash 17 is of metal and the glass sheets 18, 18 are held in position by means of the single o_nmetal plate 19 secured by the screws 20. In this case, the sealing member 21 is of the same construction as in Figs. 1 to 4.

When safety glass is used in the construction, as shown in Fig. 5, it is highly desirable that ₃₅a special form of such glass be used, in order that the transparency of the window shall be unimpaired after a long period of service. The cellulose plastic reinforcing between the sheets tends to become yellow and brittle in the course ₄₀of time, due to the decomposing action of ultraviolet light, and in order to counteract this tendency, the outer glass sheet of each pane is made with a small content of an oxide, such as iron oxide, which acts as an ultraviolet ray cut-off ₄₃medium. An amount of from .35 to 1.00 per cent of iron oxide serves to cut off the major portion of the damaging ultraviolet rays, and at the same time, adds only a slight tinge of color to the glass. The inner sheet of each ₅₀pane of glass is also preferably made from a special batch in order to avoid the phenomenon known as ‘‘efflorescence”. This is a deposit of white alkaline dust which occurs upon glass and becomes noticeable in a double glazed structure 55

2,064,530 because the inner surfaces of the glass sheets are not accessible for wiping. With dry air in the insulating space, this deposit is reduced to a minimum, but in order to further guard against 6 this defect, the inner sheets of glass are made from a batch containing from 2 to 10 per cent of potassium oxide. This has been found to reduce efflorescence to a negligible amount. The window, as thus constructed, therefore main10 tains its original appearance through a period of service in .which a window employing ordinary safety glass would become so discolored and clouded as to require replacement. Oxides other than iron oxide may be used in the glass as ulti-a15 violet cut-off ingredients, such as cerium, titanium, nickel, and chromium, and both the inner and outer sheets may have a content of both iron oxide or its equivalent, and potassium oxide, but this involves much greater cost with no added 20 advantage.