WO1979000204A1

WO1979000204A1 - Protective hood for valves with hand wheels

Info

Publication number: WO1979000204A1
Application number: PCT/SE1978/000057
Authority: WO
Inventors: A Persson
Original assignee: A Persson
Priority date: 1977-10-13
Filing date: 1978-10-10
Publication date: 1979-04-19
Also published as: SE403824B; EP0006929A1

Abstract

A protective hood, mainly cylindrical, having an end wall (8) at one end and being open at the other end, intended for fitting over valves for conduits, said valves being of the type fitted with a hand wheel. The hood (1) is made of a fabric (7), such as glass fibre fabric, able to keep out solid contaminating particles but permeable to gas and, further, heat resistant, tensioned over a frame of metal wire (10) wound to coil spring shape, so that for transport and storage the hood can be kept axially compressed to a height several times smaller than when it is expanded by the spring action of the frame. At its upper, closed end the hood is fitted with fastening means, such as clamps (13) or the like, intended to be passed over the spokes (4) of the hand wheel for retaining the hood over the valve.

Description

Protective hood for valves with hand wheels

In process industries, e.g. the cellulose industry, extensive conduit systems are used which are fitted with shut-off and control valves, such as, for example, wedge valves and similar types of valve, usually fitted with a hand wheel and manually operated. The valves are often located in an environment where, after some time, they become heavily coated with contaminants on their outside. The valves and their hand wheels are often more or less totally caked with or buried in contaminating particles which, apart from making the operation of the valves more difficult to the operators, can also cause corrosion and damage to valve spindles and bearings.

It is therefore known to fit the valves with protective hoods, which are usually made of sheet metal and more or less specially made from one application to another with regard to sizes and means for attaching them to the valves. These hoods are expensive and show other disadvantages as well. They become heavily dirtied on their outside and are also time-consuming and clumsy to fit and remove, which makes them unattractive to handle, so that the operators of the valves tend to neglect re-fitting the hoods after once having removed them. Further, it is costly, space-consuming and impractical to stock and keep in reserve the necessary number of all the various hood sizes, since it is a question of large numbers - there may be thousands of valves in one single plant.

The object of the present invention is to provide a protective hood which is light, inexpensive, simple to fit and remove, has a repelling effect on contaminating solid particles falling down on it and requires little space for transport and storing. This has been obtained by giving the protective hood the characteristics set forth in the accompanying Claims.

The invention is described in closer detail with reference to the enclosed drawing. Fig. 1 in the drawing shows a side elevation of a protective hood fitted over a wedge valve shown partly in side elevation and partly by outlines. Fig. 2 is a perspective sketch of the hood in the expanded position and fig. 3 a perspective sketch of same when compressed for transport or storage. In the drawing the numeral 1 designates a hood in accordance with the invention, 2 is a valve fitted with a hand wheel 3 with spokes 4, a nut 5 for retaining the hand wheel, and a valve spindle 6. The hood 1 is made from a fabric 7, which is suitably heat resistant and can, for example, be a glass fibre fabric. The fabric should be dense enough to give efficient protection against penetration of contaminating solid particles but should be permeable to rising air streams produced inside the hood in cases where hot media are transported in the conduit on which the valve is fitted. The hood is made in the form of a cylinder, open at one end and fitted, at the other end, with an end wall 8 with a central opening 9. The fabric of the hood is tensioned over a frame consisting of metal wire 10 wound to helical spring shape, to which the fabric is fastened at suitable points, e.g. by sewing the fabric around the wire, the spring action keeping the hood expanded in the axial direction. At the end of the hood where the end wall 8 is provided, the hood is fitted with four rods 11, arranged like the spokes of a wheel and interconnected by a ring 12 defining the central opening of the end wall, to which ring the fabric of the end wall is fastened. The rods 11 are fitted with two fork-shaped clamps 13 intended to be passed over the spokes 4 of the hand wheel.

The hoods in accordance with the invention are suitably made in a number of different sizes corresponding to different standard sizes of valves and their hand wheels. Since the frame is made in the form of a helical spring, the hoods can, for transport and storage, be compressed in the way shown in fig. 3 and can then suitably be kept in this position either direct by their packaging or, for example, by a pair of clamps 14 or similar. In this way the hoods require a minimum of transport and storage space, which is of great importance within process industries where large numbers of hoods may be needed. When a hood is to be fitted over a valve, the helical spring of the frame is released, so that the hood is expanded to its full length, whereupon the hood is fastened by passing the clamps 13 over the spokes 4 of the hand wheel of the valve. It is suitable to have the size of the hood in the axial direction so adjusted that the bottom edge of the hood will seal - under light spring pressure - against the projecting flange 15 of the valve housing or a corresponding surface. A valve spindle 6 can be passed through the central opening 9 of the hood. The ring 12 defining the central opening seals against the hand wheel nut 5 or a corresponding part, depending on the type of valve. Since the fabric of the hood is permeable to gas, the outside of the hood will to a considerable extent be self-cleaning in the many cases where hot media are transported in the conduits and the heat from these media causes rising currents of air inside the hood. The permeable hood will also function as a protection against bodily injuries caused by jets of steam or other hot media escaping from the valve, since the hood will act as a brake and spreader and, at the same time, is less inclined to be thrown off the valve due to the pressure than is a completely impermeable hood.

Claims

1. A protective hood for fitting over valves for conduits, said valves being of the type fitted with a hand wheel and said hood being substantially cylindrical, open at one end and provided with an end wall at its other end, c h a r a c t e r i z e d i n t h a t the hood (1) is made of a fabric (7), such as glass fibre fabric, able to keep out solid contaminating particles but permeable to gas and, further, heat resistant, tensioned over a frame of metal wire (10) wound to coil spring shape, so that for transport and storage said hood can be kept axially compressed to a height several times smaller than when the hood is kept expanded by the frame due to its spring action; and in that, at the upper, closed end of the hood, the frame is fitted, on its inside, with two or more clamps (13) or similar, intended to be passed over the spokes (4) of the hand wheel for retaining the hood over the valve.

2. A protective hood as claimed in claim 1, c h a r a c t e ri z e d i n t h a t the height of said hood (1), i.e. its axial extension, is so adjusted that the lower, open end of the hood will seal, under light spring pressure, against a flange (15) of the valve housing or a corresponding surface.