the locking element 32 has a slide 33 which extends as a perpendicularly arranged and radially displaceable plate from the locking element 32 to the upper side of the upper housing part 2 fig3 illustrates the slide 33 in the radially inserted state with respect to the spindle axis i e in the normal operating state of the valve 1 the slide 33 has a through opening 34 through which the cams 35 which are formed on the upper side of the upper housing part 2 pass during the rotational movement of the hand wheel 4 in the position shown in fig3 the valve 1 can be actuated with the hand wheel 4 fig4 illustrates the slide 33 in the radially withdrawn state in this position the radial position of the hand wheel 4 is fixed the hand wheel 4 cannot be actuated and the spindle 5 cannot be rotated in this position in order to secure the valve in the locked position the locking element 32 has a bore 36 into which a padlock not illustrated here or any other suitable security device can be introduced this prevents unauthorized actuation of the valve 1 as illustrated in fig5 and 6 the locking element 32 further has.