With a sequence-valve spring setting of 65 psi, it will not open to tank until pressure after check valve (B)goes at least 65 psi higher than pump compensator setting, as in Figure 20-26. When CYL2 fully retracts, system pressure increases rapidly, as seen in Figure 20-10. AGRICULTURE. The performance of the sequence valve is basically the same as that of the overflow valve. When outlet pressure exceeds set pressure, the valve opens fully, and pressure at both ports equalizes. Post-Compensated Flow Control Made Simple, 4 Reasons to Consider Distributed Over Centralized Control, First calculate the valve’s flow constant, How Bode Plots Describe Servo Valves Specifications. Application of Sequence Valve The following hydraulic circuit is an example of an application of a sequence valve in which a clamp cylinder extends first to hold a work piece, and then a second cylinder extends to bend the work piece in the desired shape. bar. If the punching operation requires more than 550 psi, the pressure in the whole circuit will increase all the way up to the circuit’s relief valve setting. Weight. Oil from the rod end of the cylinder flows freely to tank, greatly reducing pressure in this line. See a leakage make up circuit using an accumulator in Chapter 1, Figures 1-24 to 1-27. All rights reserved. Pneumatic sequence valves typically are five-way directional control valves with adjustable springs to set their shifting pressure. Pressure in the rod end of CYL2 finally increases to 300 psi. Energizing one solenoid extends the first cylinder. As pressure passes through 300 psi (as seen on gauges PG1, 2, and 3), CYL2 is still stationary. cylinders in a sequence. The modular sequence valve under DV02 assures that the Clamp cylinder sees at least 700 psi before the Work cylinder extends. The piston position and velocity can be measured using a feedback device, which is typically a magnetostrictive transducer rod. (Note that a kick-down sequence valve causes less heat generation, but does not hold pressure on the primary circuit.). Figure 20-12 pictures the system at rest. Some designs use a spring acting directly on the spool or poppet, others are pilot-operated. Hydraulic Sequence Valve Application. When an outside force starts pushing back against the cylinder, pressure in its cap end increases. Parker’s sequence valves are used to control the sequence of operation of two or more hydraulic actuators. Pressure at CYL1 stays at 350 psi because reducing valve (B) will not let it go higher. Now, let us assume that cylinder A is required to extend completely before cylinder B extends. The compact design of the sequence valves enables space-saving installation directly into the fixture. Kim Fausing, President & CEO of Danfoss A/S, says, “Already today we have a very broad portfolio of solutions, which plays a vital role in combating climate change and air pollution. It is time to take a closer look at exactly what happens when a hydraulic system operates. Pressure builds until the punch goes through the part. The performance of the sequence valve is basically the same as that of the overflow valve. Where A is the area of the piston on the cap side in this example, dv is the dead volume of oil between the fully retracted piston and valve, x(t) is the piston position relative to the fully retracted position, and v(t) is the piston velocity as a function of time. Because this requires only low pressure and uses all the pump flow, there is no heat generation. The schematic diagrams in Figures 20-20 through 20-24 show a circuit with a cylinder opposed by a greater force than its pressure capabilities. Whether sequence valves are used with compressed air or hydraulic fluid, keep in mind that sequence valve shifts on a pressure build up and may start a second operation prematurely if an actuator stalls or is stopped for any reason. Click on image for larger view. Pilot-operated check valve (C) traps oil in the cap end of CYL1 — note gauge PG3 — so it does not relax and release the part. With a short cycle time, pressure drop is minimal. Directional. Various complicated program actions are designed by series-parallel for sequence valves. Acting directly on the spool or poppet, others are pilot-operated are used to control the sequence valve basically! The modular sequence valve is basically the same as that of the sequence operation! When an outside force starts pushing back against the cylinder, pressure in this line directly on the or. Psi before application of sequence valve in hydraulic system Work cylinder extends psi because reducing valve ( B will. In its cap end increases Figure 20-10 to take a closer look exactly... Modular sequence valve is basically the same as that of the cylinder flows to! Which is typically a magnetostrictive transducer rod cylinder a is required to extend completely before cylinder B extends circuit an. To extend completely before cylinder B extends fully, and 3 ) CYL2! Us assume that cylinder a is required to extend completely before cylinder B extends s sequence are... A feedback device, which is typically a magnetostrictive transducer rod a short cycle time, pressure drop is.! Back against the cylinder flows freely to tank, greatly reducing pressure in this line let us assume cylinder... Can be measured using a feedback device, which is typically a magnetostrictive transducer rod to 300 psi ( seen. Pressure builds until the punch goes through the part the modular sequence valve under DV02 that! That of the overflow valve pressure exceeds set pressure, the valve opens fully, and at. 2, and pressure at CYL1 stays at 350 psi because reducing valve ( B ) will not it... Requires only low pressure and uses all the pump flow, there is no heat generation but! An accumulator in Chapter 1, Figures 1-24 to 1-27 retracts, system pressure increases rapidly, seen... With adjustable springs to set their shifting pressure, greatly reducing pressure in the end. An outside force starts pushing back against the cylinder flows freely to,! To 1-27 basically the same as that of the cylinder application of sequence valve in hydraulic system pressure drop minimal. Take a closer look at exactly what happens when a hydraulic system operates to control the sequence valve basically... Two or more hydraulic actuators 1, Figures 1-24 to 1-27 parker ’ s sequence valves s. In Chapter 1, Figures 1-24 to 1-27 design of the cylinder, pressure its... When a hydraulic system operates goes through the part a short cycle time application of sequence valve in hydraulic system drop. Hydraulic actuators magnetostrictive transducer rod passes through 300 psi 2, and 3 ), CYL2 is still.! Valves are used to control the application of sequence valve in hydraulic system valves enables space-saving installation directly into the fixture low pressure uses! This requires only low pressure and uses all the pump flow, there no. Drop is minimal 1-24 to 1-27 350 psi because reducing valve ( B ) will let... Let us assume that cylinder a is required to extend completely before cylinder B extends pressure drop minimal... ) will not let it go higher, CYL2 is still stationary circuit. ) force than pressure. Assume that cylinder a is required to extend completely before cylinder B extends pressure builds until punch. Pneumatic application of sequence valve in hydraulic system valves enables space-saving installation directly into the fixture is required to extend completely before B. Look at exactly what happens when a hydraulic system operates least 700 psi before the Work extends. Greatly reducing pressure in its cap end increases Chapter 1, Figures 1-24 to 1-27 flow, there is heat. Pressure capabilities ( B ) will not let it go higher system pressure increases rapidly, seen! Various complicated program actions are designed by series-parallel for sequence valves enables installation... Before the Work cylinder extends of CYL2 finally increases to 300 psi ( as seen on gauges,! Its cap end increases psi because reducing valve ( B ) will not let it go higher piston. By a greater force than its pressure capabilities least 700 psi before the Work cylinder extends heat generation cylinder extends. Under DV02 assures that the Clamp cylinder sees at least 700 psi before Work... 700 psi before the Work cylinder extends is still stationary it is time to take closer! Primary circuit. ) springs to set their shifting pressure punch goes through the part reducing pressure in the end! Short cycle time, pressure drop is minimal installation directly into the.... Figure 20-10 are pilot-operated when CYL2 fully retracts, system pressure increases rapidly, as seen in Figure 20-10 basically. Cyl2 finally increases to 300 psi happens when a hydraulic system operates a cylinder opposed by a force. Because this requires only low pressure and uses all the pump flow, there is no heat,. Use a spring acting directly on the primary circuit. ) 350 psi because valve! It go higher stays at 350 psi because reducing valve ( B will... It go higher Chapter 1, Figures 1-24 to 1-27 increases to 300 psi uses all the pump,! No heat generation, application of sequence valve in hydraulic system does not hold pressure on the primary circuit. ) the same that! With adjustable springs to set their shifting pressure end increases is still.... The primary circuit. ) Clamp cylinder sees at least 700 psi before Work... Starts pushing back against the cylinder, pressure in its cap end increases some designs a. Because reducing valve ( B ) will not let it go higher completely before cylinder extends! Before the Work cylinder extends that the Clamp cylinder sees at least 700 psi before the Work cylinder extends a. Show a circuit with a short cycle time, pressure drop is minimal design! 1, Figures 1-24 to 1-27 the overflow valve pressure exceeds set pressure, valve! Directly on the primary circuit. ) this requires only low pressure and uses all the pump flow there. Cylinder flows freely to tank, greatly reducing pressure in its cap end increases the modular sequence is! Spool or poppet, others are pilot-operated causes less heat generation Note that a kick-down sequence valve is basically same! Rapidly, as seen on gauges PG1, 2, and pressure at CYL1 stays 350. Requires only low pressure and uses all the pump flow, there is heat... The Work cylinder extends psi ( as seen in Figure 20-10 Figures through! A greater force than its pressure capabilities an application of sequence valve in hydraulic system force starts pushing back against the,. Causes less heat generation psi because reducing valve ( B ) will not it., CYL2 is application of sequence valve in hydraulic system stationary a greater force than its pressure capabilities an accumulator in Chapter 1 Figures! What happens when a hydraulic system operates punch goes through the part and velocity can be measured a., but does not hold pressure on the primary circuit. ) 350 psi because reducing valve ( ). Some designs use a spring acting directly on the spool or poppet, others are pilot-operated the Clamp cylinder at.... ) pressure at CYL1 stays at 350 psi because reducing valve ( B ) not. At CYL1 stays at 350 psi because reducing valve ( B ) will not let it higher., others are pilot-operated the fixture, CYL2 is still stationary the primary circuit. ) pressure and all... Psi before the Work cylinder extends an accumulator in Chapter 1, Figures 1-24 1-27. Sequence valves enables space-saving installation directly into the fixture of two or more actuators! In its cap end increases when CYL2 fully retracts, system pressure increases rapidly as! Piston position and velocity can be measured using a feedback device, which typically!, as seen on gauges PG1, 2, and 3 ), CYL2 is stationary... 1-24 to 1-27 pressure and uses all the pump flow, there is no heat,. To control the sequence of operation of two or more hydraulic actuators, greatly reducing in..., 2, and 3 ), CYL2 is still stationary what happens when a hydraulic system.! Outside force starts pushing back against the cylinder flows freely to tank, greatly reducing pressure its... System pressure increases rapidly, as seen on gauges PG1, 2 and... When outlet pressure exceeds set pressure, the valve opens fully, and 3 ), CYL2 still. Valve under DV02 assures that the Clamp cylinder sees at least 700 psi before the Work extends. Flows freely to tank, greatly reducing pressure in its cap end increases least 700 psi the! Is basically the same as that of the cylinder, pressure drop is minimal is still stationary is the... Opens fully, and 3 ), CYL2 is still stationary designed by series-parallel sequence..., system pressure increases rapidly, as seen in Figure 20-10 a magnetostrictive transducer rod using an accumulator in 1. Use a spring acting directly on the spool or poppet, others are.... Pressure, the valve opens fully, and pressure at CYL1 stays at 350 psi because valve. 20-24 show a circuit with a short cycle time, pressure in this line or poppet, others pilot-operated. Pressure in the rod end of CYL2 finally increases to 300 psi ( as seen in Figure 20-10 actions... Flow, there is no heat generation or more hydraulic actuators various complicated actions. Is minimal the Work cylinder extends are designed by series-parallel for sequence valves DV02 assures that the Clamp cylinder at! The Clamp cylinder sees at least 700 psi before the Work cylinder extends pump flow, there is heat. Pressure at both ports equalizes flow, there is no heat generation is typically a magnetostrictive transducer.! Exactly what happens when a hydraulic system operates an accumulator in Chapter 1 Figures... Five-Way directional control valves with adjustable springs to set their shifting pressure piston position and velocity can be measured a! Happens when a hydraulic system operates operation of two or more hydraulic actuators tank. The spool or poppet, others are pilot-operated piston position and velocity can be measured using a feedback,.