portion 49 of valve operator 40 close off the space surrounding valve stem 50 sealing means other than o ring seals 51 and 52 may be used the upper end of a conduit 53 connects into the upper end of cylinder 44 through passageway 53a conduit 53b and passageway 53c the lower end of conduit 53 connects into a conduit 54 which extends through the upper end of valve housing 41 consuit 54 is equivalent to conduit 30 of fig1 and is therefore connected to an accumulator such as 29 through a valve such as 32 the upper end of another conduit 55 connects into the lower end of cylinder 44 below piston 45 through passageway 55a and also into the interior of housing 42 the lower end of conduit 55 connects into a conduit 56 which extends through the upper end of valve housing 41 conduit 56 is equivalent to conduit 31 and is therefore connected to a reservoir such as 25 through a valve such as 32 the remainder of the apparatus for connecting valve operator 40 to valve housing 41 generally indicated at 61 will be described in more detail with reference to fig4 a to 4f a seal 62 fig2 seals off fluid flow into or from the interior of valve housing 41 when the valve operator 40 is clamped onto valve housing 41 by clamp 63 clamp 63 is similar to the clamp connector described and claimed in u s patent.