GB2099540A

GB2099540A - Sight glass fitting

Info

Publication number: GB2099540A
Application number: GB8210942A
Authority: GB
Original assignee: SCHULZ AND CO KG
Current assignee: SCHULZ AND CO KG
Priority date: 1981-04-18
Filing date: 1982-04-15
Publication date: 1982-12-08
Also published as: DE3145086A1; DE3145086C2; FR2504258A1; GB2099540B; CH654895A5

Abstract

The invention relates to a sight glass fitting, which consists of a pipe section in which apertures provided on diametrally opposite sides are covered fluid-tightly by glass panes. According to the invention the apertures (4) covered by the glass panes (3) are arranged eccentrically with reference to the central longitudinal axis of the pipe section, to avoid having a recess in which dirt can accumulate. <IMAGE>

Description

SPECIFICATION Sight glass fitting The invention relates to a sight glass fitting, consisting of a pipe section in which apertures provided on diametrally opposite sides are covered fluid-tightly by glass panes.

Sight glass fittings which are installed upstream or downstream of shut--off fittings in pipes or on tanks, serve for the observation of the flowing medium as regards colour, consistence or degree of pollution. Known sight glass fittings are produced by die casting and exhibit a tubular section, at the opposite open ends of which fixing flanges are integrally shaped, welded on or placed.

In the central section, pipe stubs with flanges are likewise shaped integrally or welded on on diametrally opposite sides of the cylinder envelope. The former flanges serve for the installation of the sight glass fitting into the pipe, the latter flanges for the fixing of the glass panes, which are generally fixed detachably by means of a flange ring with interposition of sealing rings, to enable them to be exchanged when damaged or to be cleaned.

The production of the known sight glass fitting by the die casting process is comparatively expensive because a particular pattern has to be prepared for each dimension and the casting has to take place individually. Since there are also continual changes in the materials of which the sight glass fittings are required to consist, namely a similar material to the pipe into which they are to be installed, a comparatively expensive individual production is necessary. Since moreover the wall thickness of the cast products is comparatively great, a high use of material is necessary. Furthermore, the pipe stubs to which the transparent panes are attached by flanges form dead spaces in which dirt settles, so that the view through the sight glass becomes impaired in time.

In German Offenlegungsschrift 29 33 939 a more economic production of such sight glass fittings is rendered possible in that integrally shaped plane support surfaces for the glass panes are provided on the pipe section in the region round the apertures. By this means dead spaces are avoided, so that the view through the glass panes is not impaired by settled dirt even when the fitting is in service for long periods.

In the case of this known sight glass fitting a section of the pipeline into which the sight glass fitting is required to be installed is used in order to produce the same. This section then consists of the same material as the pipeline and therefore no problems of different material matching arise. It has a smaller wall thickness than a die casting product, and therefore requires less material and is less expensive for this reason alone. The formation of the support surfaces for the glass panes of the sight glass fitting, in the region of the apertures provided on diametrally opposite sides of the pipe envelope, which are required to be covered fluidtightly by the pane, can be performed in a very simple production technique by pressing on, which reduces the production costs.

The underlying aim of the invention is to produce a sight glass fitting for installation into horizontally oriented pipelines or at horizontal outlets from tanks, which is economic to produce and in which settling of dirt, which would cloud the view through the sight glass fitting or render cleaning difficult, cannot occur. The diameter of the glass panes inserted is preferably equal to or greater than the diameter of the pipe section of the fitting.

According to the invention there is provided a sight glass fitting, consisting of a pipe section having a central longitudinal axis in which section lateral apertures provided on diametrally opposite sides are covered fluid-tightly by glass panes, characterised in that the said apertures are arranged eccentrically with reference to the said axis. The eccentric arrangement of the glass panes with reference to the axis of the pipe section of the sight glass fitting is intended according to the invention to be made so that no recess is formed in the lower part of the pipe section, as is generally the case with the conventional sight glass fittings.

Preferably the apertures are offset eccentrically with reference to the axis of the pipe section to the extent that a protruberance beyond the pipe section when seen side-on is present for the accommodation of each glass panel only to one side of the centre of the section.

Due to the absence of any recess in the lower part of the pipe section of the sight glass fitting, no settling of dirt occurs. Consequently the view through the sight glass fitting remains unclouded even during long periods of service, and no cleaning problems arise.

The production of the sight glass fitting according to the invention can be economical, because either the apertures which are covered by glass panes are necked out by cold pressing, i.e.

are shaped integrally, from a pipe section of the same material as that of the pipeline, or else the outlet pipes of smaller diameter are likewise necked out by cold pressing from a tubular section having the diameter of the sight apertures covered by the glass panes.

According to an advantageous further development of the sight glass fitting, plane support surfaces for the glass panes may be shaped on and located as close as possible to the pipe envelope. This, on the one hand, reduces the external circumference of the sight glass fitting, and also prevents the creation of dead spaces. The glass panes may be connected by flanges to the plane support surfaces with interposition of a seal in simple manner.

If, according to a further advantageous development of the sight glass fitting, the glass pane is inserted into the aperture with slight play between a stop shoulder and a circlip and the peripheral gap is sealed by an inserted sealing ring, then the sealing occurs quasi spontaneously under internal pressure in the sight glass fitting.

I.e., the complicated manipulation during the carefully uniform tightening of flange fixing screws by means of torque wrenches, which is a necessary condition for a uniformly tight contact of flange-connected glass panes, is eliminated.

The slight play with which the glass pane is inserted between the stops ensures stress-free installation and uniform sealing on the circumference at all times. It is also particularly advantageous that screws and flanges for the fixing of the glass panes can be eliminated. These additional parts, which also occupy considerable space, thus become superfluous. Besides the facilitation during assembly, a cost advantage thus also results by the elimination of components.

The glass pane may be fused into a metal ring, which may also exhibit one or more grooves in its external periphery for the insertion of sealing rings.

The durability of the glass pane is increased by this means, since it does not break so rapidly. The advantage of improved accessibility to the interior of the fitting during cleaning and an easier and more rapid assembly during exchange of the glass panes is also achieved. It is only necessary to remove the circlip, to extract the glass pane, to reinsert a new one, or the same one cleaned, and to insert the circlip. The glass pane with metal ring is prepared complete with the sealing ring for installation. Because there is no need to provide a groove for the sealing ring in the metal housing of the fitting, it can consist of thinner material and is simpler to machine.

The invention is explained with reference to the exemplary embodiments of the sight glass fitting according to the invention illustrated in the drawing.

Fig. 1 shows a longitudinal section through an exemplary embodiment, Fig. 2 shows the related cross-section, Fig. 3 shows, in cross-section on a larger scale, the sight aperture illustrated in the right-hand half of the fitting according to Fig. 1, and Fig. 4 the same in a variant construction of Fig. 3, Fig. 5 is a longitudinal section, and Fig. 6 is a cross-section of a further exemplary embodiment of the invention.

The sight glass fitting consists of the pipe section 1, at the opposite open ends of which flanges 2 are shaped on, welded to or on or placed on. They serve to fix the sight glass fitting in a horizontally laid pipeline, not shown, or in the horizontal outlet on a tank or a shut-off fitting.

Apertures 4, which permit a view through the medium flowing through the pipe section 1, are provided on diametrally opposite sides in the central part of the pipe section 1. As may be seen best from Fig. 2, these apertures are arranged eccentrically with reference to the axis of the pipe section 1, 50 that no recess is created in the lower part of the pipe section 1. The lower edge of the glass pane 3 covering the aperture 4 lies approximately in one plane with the lowest envelope line of the pipe section 1.

Different exemplary embodiments for the insertion of the glass panes into the sight glass fitting are illustrated in the drawing.

In the embodiment illustrated in the left-hand part of Figs. 1 and 2, plane support surfaces 6 are shaped integrally by cold pressing on the pipe section 1, and the glass panes 3 are laid upon them with inter-position of a seal and are fixed to the pipe section 1, covering and sealing the apertures 4, by means of a screwed-on flange ring 7.

According to the right-hand part of Figs. 1 and 2, the glass panes 3 may however also be inserted into a tubular necking-out 8 on the pipe section 1.

The necking-out 8, which may be formed by integral shaping by cold pressing, exhibits internally a stop shoulder 9, a peripheral groove into which a sealing ring 12 is inserted, and a further groove for the insertion of the circlip 10 as an outer limitation for the axial mobility of the glass pane 3, which can move by the residual interval s. Sealing occurs by means of the sealing ring 12, which packs the gap between the necking-out 8 and the peripheral surface of the round glass pane 3, and which is somewhat compressed by the inserted glass pane 3.

Under an internal pressure, the glass pane 3 is pressed outwards by the amount s into abutment against the stop ring 1 1, against which the glass pane 3 has uniform contact. The escape of medium is efficaciously prevented by the sealing ring 12.

In the exemplary embodiment illustrated in Fig. 4 the glass pane 3 is fused into a metal ring 13. The sealing ring 12 is inserted into a groove which is worked in the external peripheral surface of the metal ring 13. Thus completed, the glass pane is pushed into the tubular necking-out 8 and fixed by means of a circlip 10. When the glass pane 3 is inserted into the necking-out 8, the sealing ring 12 is somewhat compressed and efficaciously seals the gap between the metal ring peripheral surface and the necking-out 8.

In the exemplary embodiment of the sight glass fitting according to the invention illustrated in Figs. 5 and 6, the metallic fitting housing consists of a tubular section 8a, out of the envelope of which the pipe outlets 1 a are shaped integrally by cold pressing on opposite sides and provided with connecting flanges to the pipeline. The pipe outlets 1 a defined the pipe section for transit of fluid. The apertures 4 on opposite sides of the tubular section 8a are covered fluid-tightly by the glass panes 3 in the same manner as previously described. This embodiment conforms to standard recommendations as regards the size of the viewing apertures 4.

Claims

1. Sight glass fitting, consisting of a pipe section having a central longitudinal axis in which section lateral apertures provided on diametrally opposite sides are covered fluid-tightly by glass panes, characterised in that the said apertures are arranged eccentrically with reference to the said axis.

2. Sight glass fitting according to Claim 1, characterised in that the apertures are arranged offset eccentrically with reference to the axis of the pipe section to the extent that a protruberance beyond the pipe section when seen side-on is present for the accommodation of each glass panel only to one side of the centre of the pipe section.

3. Sight glass fitting according to Claim 1 or 2, characterised in that the diameter of the apertures is greater than the diameter of the pipe section.

4. Sight glass fitting according to any of Claims 1 to 3, characterised in that the pipe section exhibits plane support surfaces for the glass panes, shaped integrally and made by cold pressing in the region round the apertures.

5. Sight glass fitting according to Claim 4, characterised in that the plane support surfaces are located as close as possible to the envelope of the pipe section.

6. Sight glass fitting according to Claim 3 comprising a tubular section having the diameter of the apertures to be covered fluid-tightly by glass panes, from which by cold pressing on opposite sides of the walls two lateral pipe outlets, eccentric relative to the central axis of the tubular section, are necked out to form the pipe section.

7. Sight glass fitting according to any of Claims 1 to 6, characterised in that the glass pane is inserted with play(s) and that the gap between the necking-out or the pipe section and the external peripheral surface of the glass pane is sealed by a sealing ring inserted into a groove.

8. Sight glass fitting according to any of Claims 1 to 6, characterised in that the glass pane is fused into a metal ring, in the external peripheral surface of which one or more grooves are provided for the insertion of sealing rings.

9. Sight glass fitting substantially as hereinbefore described with reference to Figs. 1 and 2, or 3, or 4, or 5 and 6 of the accompanying drawings.