Direct acting sequence valves are spool-type devices that allow multiple functions to operate in sequence without the need for solenoid valves, limit switches, or complex control systems. Parker’s B02, B04, and SV10 sequence valves provide design options for 2-position 2-way or 2-position 3-way sequencing with pilot signals and drains provided internally or externally. Externally drained versions are not sensitive to downstream pressure if they are drained to the tank. One or more sequence valves can be used in a circuit to allow multiple functions to operate in a specific order based on pressure. Normally closed and normally open versions are available to allow for design flexibility. Parker’s B04H4, B04J4, and SV104 series of direct acting sequence valves are Externally Piloted and Externally Drained. The Normally Closed B04H4 is a 2-position 2-way valve that blocks flow in both directions until an external pilot supply pressure overcomes the sequencing setting. B04J4 and SV104 are Normally Open 2-position 2-way valves that allow bi-directional flow until the external pilot supply reaches the sequence setting. All three valves are insensitive to back pressure when their drain line is connected to tank. Parker’s B04F3, B04G3, B04K4, and SV105 series of direct acting sequence valves are Externally Piloted and Internally Drained. The Normally Closed B04F3 and SV105 are 2-postion 2-way valves that prevent flow from passing from port 3 to 2 until an external pilot supply pressure overcomes the sequencing setting. Once the sequence pressure is reached the valve will open allowing flow from port 3 to 2. B04G3 is a 2-position 2-way Normally Open valve that allows flow from port 2 to 3 until the external pilot pressure reaches the sequence pressure blocking flow from 2 to 3. B04K4 is a 2-position 3-way normally open valve that allows bi-directional flow between ports 2 and 3 until the sequence pressure is met. Once the pilot pressure exceeds the set pressure, port 2 is blocked and flow is allowed from port 3 to port 4. The internal drain causes downstream pressure to be additive to the valves pressure setting, therefore it is most common for the downstream port to be connected to tank. Parker’s B02E3F and B04E3 direct acting 2-position 3-way sequence valves are Internally Piloted and Internally Drained. Flow from port 2 to 1 is normally open until the pressure at port 1 exceeds the valves setting which closes port 3 and allows flow from port 1 to port 2. Parker’s SV103 direct acting 2-position 3-way sequence valve is Internally Piloted and Externally Drained. Flow from port 1 to 2 is Normally Closed until the pressure at port 1 exceeds the sequence setting which allows flow from port 1 to 2. Port 3 is a dedicated spring chamber vent which makes the valve insensitive to downstream pressure at port 2. Common Applications include: Dump Circuits, High Low Systems, Agriculture, Power units, Construction, Material-Handling……