Method of joining a ceramic plug tip and a steel support member using a threaded joint and an adhesive

A method of joining a valve plug assembly comprising:

• providing a metal support member having a support member body having a support member first end and a support member second end opposite the support member first end;
• forming a first mating feature on the support member, the first mating feature being disposed proximate the support member first end, and the first mating feature having a threaded portion;
• forming a stem mating feature on the support member, the stem mating feature being disposed proximate the support member second end, wherein the stem mating feature is adapted to secure the support member to a valve stem;
• providing a ceramic plug tip having a plug tip first end and a plug tip second end opposite the plug tip first end;
• forming a second mating feature on the plug tip, the second mating feature being disposed adjacent the plug tip second end, and the second mating feature having a threaded portion;
• forming a plug sealing surface on the plug tip, the plug sealing surface being disposed proximate the plug tip first end, wherein the plug sealing surface is adapted to sealingly engage a valve seat;
• applying an adhesive to at least one of the threaded portion of the first mating feature and the threaded portion of the second mating feature;
• threadingly engaging the threaded portion of the first mating feature to the threaded portion of the second mating feature such that the adhesive contacts at least a portion of the threaded portion of the first mating feature and at least a portion of the threaded portion of the second mating feature and such that a portion of the threaded portion of the first mating feature of the support member is in contact with a portion of the threaded portion of the second mating feature of the plug tip;
• and
• curing the adhesive by heating the support member, the plug tip, and the adhesive to a temperature that does not exceed 400° F.

A fluid control valve comprising:

• a valve body having a fluid inlet, a fluid outlet, a passageway in fluid communication with the fluid inlet and the fluid outlet, and a valve seat in the passageway for controlling the fluid flow;
• an elongated valve stem having a valve stem first end and a valve stem second end, the valve stem first end being adapted to be coupled to a valve actuator, and the valve stem second end opposite the valve stem first end;
• a valve plug assembly coupled to the second end of the valve stem, the valve plug assembly comprising:
• a support member having a support member body extending along a support member longitudinal axis from a support member first end to a support member second end opposite the support member first end, the support member also having an axially disposed first mating feature disposed adjacent the support member first end, wherein the first mating feature has a threaded portion, the support member also having a stem mating feature disposed proximate to the support member second end, and at least a portion of the valve stem second end is coupled to the stem mating feature to secure the support member to the valve stem, and wherein the support member comprises a metal material;
• a plug tip extending along a plug tip longitudinal axis from a plug tip first end to a plug tip second end opposite the plug tip first end, the plug tip also having an axially disposed second mating feature disposed adjacent the plug tip second end, wherein the second mating feature has a threaded portion, the plug tip also having a plug sealing surface disposed proximate the plug tip first end, the plug sealing surface being adapted to sealingly engage the valve seat, and wherein the plug tip comprises a ceramic material;
• and
• an adhesive,
• wherein the threaded portion of the first mating feature of the support member engages the threaded portion of the second mating feature of the plug tip such that a portion of the threaded portion of the first mating feature of the support member is in contact with a portion of the threaded portion of the second mating feature of the plug tip, and
• wherein the adhesive bonds to at least a portion of the threaded portion of the first mating feature and at least a portion of the threaded portion of the second mating feature to secure the plug tip to the support member.