Abstract: Apparatus to bias spool valves using supply pressure are disclosed. An example apparatus includes a sleeve of a spool valve, and a spool within the sleeve to control a flow of fluid at a supply pressure through the spool valve as the spool is moved relative to the sleeve in response to a variable input force. A biasing force is to bias the spool opposite the variable input force. The biasing force is to be generated from a biasing pressure of the fluid within a chamber adjacent a biasing end of the spool. The biasing pressure is to be based on the fluid at the supply pressure provided directly to the chamber from a supply of the fluid independent of the flow of the fluid through the spool valve.

Abstract: Apparatus to bias spool valves using supply pressure are disclosed. An example apparatus includes a sleeve of a spool valve, and a spool within the sleeve to control a flow of fluid at a supply pressure through the spool valve as the spool is moved relative to the sleeve in response to a variable input force. A biasing force is to bias the spool opposite the variable input force. The biasing force is to be generated from a biasing pressure of the fluid within a chamber adjacent a biasing end of the spool. The biasing pressure is to be based on the fluid at the supply pressure provided directly to the chamber from a supply of the fluid independent of the flow of the fluid through the spool valve.

Abstract: Hard coated spool valves are disclosed. An example spool valve includes a sleeve and a spool to be positioned within the sleeve. The sleeve and the spool are made of a corrosion resistant material. The spool valve includes a wear resistant coating on at least one of the spool or the sleeve.

Abstract: Methods and apparatus to bias spool valves using supply pressure are disclosed. An example apparatus includes a housing of a spool valve, the housing including a first port to receive a fluid at a supply pressure. The example apparatus further includes a spool within the housing. A position of the spool is to be selectively controlled via an input force acting on the spool, the position of the spool to define a path of a flow of the fluid through the spool valve from the first port to a second port of the housing. A biasing force is to bias the spool opposite the input force, the biasing force to be generated from the supply pressure applied to an end of the spool.

Abstract: Methods and apparatus to bias spool valves using supply pressure are disclosed. An example apparatus includes a housing of a spool valve, the housing including a first port to receive a fluid at a supply pressure. The example apparatus further includes a spool within the housing. A position of the spool is to be selectively controlled via an input force acting on the spool, the position of the spool to define a path of a flow of the fluid through the spool valve from the first port to a second port of the housing. A biasing force is to bias the spool opposite the input force, the biasing force to be generated from the supply pressure applied to an end of the spool.