Protective fluid system

A protective fluid system comprising a fluid pump and a fluid control valve and a fluid protective valve and a fluid motor means, all fluid-flow connected together with fluid lines and having said protective valve positioned closest to said fluid motor means and said fluid control valve being positioned between said pump and said fluid protective valve, said fluid motor means having two fluid-flow capacity requirements respectively with each separately fluid-flow connected with said protective valve, said protective valve having a valve body with two fluid-flow separated compartments, an elongated valve spool disposed in said valve body and having each end extending into a respective one of said compartments and being axially movable therein, each end of said spool having two fluid-flow closure portions thereon and also having a projection interposed between said two closure portions with fluid-flow orifices extending through said projections in the longitudinal axial direction of said spool, spool-centering springs in said valve body and acting on said spool for positioning said spool in a centered position to have fluid flow between said passageways in each of said pair of passageways, said orifices in said respective projections being of a total fluid-flow capacity equally proportioned relative to said two fluid-flow capacity requirements of said motor means to effect equal fluid pressure drop through said respective orifices when said motor means is experiencing fluid flow of its said two fluid-flow capacity requirements, said body having a pair of fluid-flow passageways extending into each of said two compartment and with the latter said passageways being spaced apart on said body in the longitudinal axial directions of said spool, said projections disposed on said spool to be positionable intermediate said passageways of each said pair of passageways and have said orifices respectively receive all the flow of fluid between said passageways in each said pair of passageways, said closure portions on each end of said spool disposed on said spool to be respectively positionable to one side of each of said pairs of passageways, in one axial position of said spool for the flow of fluid between said passageways in each of said pair of passageways and through said orifices, and to be respectively positionable between said passageways in each of said pair of passageways, in another axial position of said spool, to block the flow of fluid between said passageways in each of said pair of passageways, whereby an unequal fluid pressure drop through said orifices and thus on oposite sides of said projections axially shifts said spool for the blocking of fluid flow, said fluid control valve being of a type to create fluid back pressure in said fluid line connected therewith, whereby opening of said fluid control valve does not simulate a break in said fluid line to trigger said protective valve, and said protective valve being operable for blocking of fluid flow for breaks in said fluid line which do not effect a back pressure therein.