Downhole valve for paraffin control

Claim 1

In an oil well having a production string concentrically disposed within a borehole to form an annulus therebetween, a production pump at the end of the production string for pumping fluid up through the production string, a string of sucker rod leading down through the production string for actuating the pump from the surface of the ground, the improvement comprising: a tool sub, means series connecting said sub within the production string at an intermediate position thereof; said sub having an axial passageway formed therethrough, with the sucker rod extending through said axial passageway in spaced relationship to the side walls thereof; an enlargement forming part of said sub and radially extending away from said axial passageway; means defining a lateral passageway within said enlargement through which fluid can flow from said axial passageway into the casing annulus; means forming a working chamber which is in communication with said lateral passageway; a valve means positioned within said working chamber for controlling the flow of fluid through said lateral passageway; said valve means includes a valve seat positioned within said lateral passageway, a valve element, a piston, a cylinder, and a spring means; said valve element normally being forced into sealing engagement with said valve seat to prevent flow through said passageway, said piston having opposed ends with one end thereof being engaged against said valve element, said piston being reciprocatingly received in sealed relationship within said cylinder with said spring means being located within said cylinder and forced into engagement with the end of said piston which is opposed to said valve element, adjustment means by which said cylinder is forced towards said valve seat to thereby vary the biasing force of said spring means; said end of said piston which is reciprocatingly received within said cylinder includes a reduced diameter marginal portion arranged such that said piston and cylinder form a variable chamber therebetween; means forming a bleed passageway from said axial passageway into said variable chamber; said lateral passageway includes an outlet which is formed between said piston and said valve seat so that when said valve element is displaced from said seat, flow can occur from said axial passageway, through said lateral flow passageway, including said seat, and into the annulus.