the valve is in the fully open condition the shield 66 extends less than about 90 of the length of the valve spring 60 the shield member 66 as illustrated in the preferred embodiment of the invention is cylindrical in shape and formed of a solid corrosion resistant metallic material however the shield 66 may suitably be formed in other shapes such as conical and any other suitable shapes so long as the shape selected does not adversely interfere with the flow of fluid and give rise to disadvantageous flow disturbances the shield may also be formed of any other suitable materials such as plastics and the like and the shield may have holes or perforations 76 formed in the walls thereof as illustrated in fig6 which will enhance fluid flow while maintaining protection of the spring from serious flow disturbances installation of the shield member 66 in valve 10 may be accomplished by various techniques for example as depicted in fig3 5 elbow members 68 are affixed to the shield 66 by any suitable means such as welding adhesive and like techniques and these elbows 68 are provided with bolt appertures 70 through which bolts 72 are applied to enable bolt connection of elbow 68 to the cover plate 20 of valve 10 in an alternative embodiment.