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Views: 0 Author: Site Editor Publish Time: 2026-10-12 Origin: Site
When a second valve is added, the first valve still has to return oil from its actuator. A hose drawn from its outlet to the next valve's inlet hides that return flow. The proposed circuit therefore needs two identified routes leaving the first valve: a pressure-capable carry-over route to the next bank and an appropriate route for exhaust oil to tank.
The BLINCE P40 monoblock directional valve lists power beyond as an option. Its public page does not identify the carry-over hardware or outlet on a particular build. That missing detail matters at the ordering stage: the selected P40 drawing must match the machine's pump, center arrangement, downstream pressure duty and tank-return route.
In a common fixed-displacement, open-center circuit, pump oil passes through the upstream valve's center passage while its spools are neutral. A carry-over outlet can continue that pressure path to another valve. Oil exhausted by a moving actuator belongs on a separate return path; Cross Manufacturing explains that separation in its power-beyond option documentation. What the second valve receives while an upstream spool is shifted depends on the selected circuit, not the phrase “power beyond” alone.
An existing machine may have carry-over and a dedicated return, or it may have only a tank outlet. Counting hoses will not tell you which: pilot and case-drain lines can resemble the main hydraulic lines. Use the machine schematic and port marks to identify each route, then have it inspected before changing hardware.
BLINCE describes the P40 as a parallel-circuit monoblock valve and lists power beyond as an option. The public family table includes flow, pressure, back-pressure and lever-count figures; the sections below use those figures where each one affects the circuit. They identify a valve family, not the exact route into a second bank. Ask BLINCE for the selected build's maximum-pressure duty, back-pressure measurement point, spool loss at working viscosity and carry-over rating. The family table does not supply them.
There is no sleeve or plug part number, power-beyond port lettering, dimensional drawing or option-code matrix on that page either. In the quote review, put the proposed configuration sheet beside the machine sketch. The sheet should show the inlet, carry-over, return, spool and relief arrangement, and name any conversion hardware. Pump flow and pressure measured on the machine then have somewhere definite to be compared; “40 L/min” alone has no such context.
BLINCE's directional-control valve category lists other families if the circuit needs a different construction or a larger bank. Its multi-directional valve overview discusses the monoblock and sectional choices. For the proposed P40, obtain its carry-over and return-path drawing first.
Begin at the pump. Trace its feed to the upstream valve and mark the highest flow expected at operating speed, the relief or compensator, the inlet rating and the line size. If a priority device feeds steering first, place it on this line too. The amount available at the P40 is the amount after that device, not the pump's nameplate output.
At the P40, separate the proposed carry-over line from the exhaust line. Carry-over should run to the next valve's pressure inlet through hardware approved for the chosen P40 build and the downstream pressure duty. The BLINCE option code, port drawing and sleeve or plug specification must identify that hardware; a threaded opening alone cannot. Mark the designated exhaust port and its reservoir connection as a distinct route. Its return-gallery allowance may differ sharply from the carry-over pressure rating.
Trace the downstream valve's return independently. Note its peak exhaust flow, tank-port limit and route into the reservoir. If it shares a final hose with the P40 return, mark the junction rather than drawing two lines that appear independent all the way to tank. The common section must be assessed at the combined return-flow condition. Actual port letters and conversion parts belong on this sketch only after the selected BLINCE drawing establishes them.
For its Series B valve, Cross warns against feeding a second valve from the ordinary outlet and specifies a power-beyond option in its service manual. A Summit P40 installation document draws separate downstream pressure and tank connections for Summit's valve. These are useful circuit examples. Their port letters, plugs and seals do not identify BLINCE parts: two valves called P40 may have different cavities, threads and relief layouts.
On a proposed sketch, move the first actuator and follow its exhaust oil. If the line drawn to the second valve is also meant to carry that exhaust, the first valve's return gallery and seals would need an explicit rating for the resulting pressure. The selected P40 port map must settle this before a connection is specified.
Start at neutral, with every spool centered. Where does oil go while the operator is doing nothing? A fixed-displacement pump paired with an open center needs an onward passage for its continuing flow; the approved carry-over route can serve that purpose. A compensated or load-sensing pump changes the neutral-flow question, so the pump schematic must sit beside the valve center symbol. The Cross service manual illustrates center mismatches for its valves; its parts are not a BLINCE conversion guide.
The pump may keep delivering near-constant flow, destroke through a compensator or follow a load-sense signal. Identify which happens with the spools centered and whether a steering circuit takes priority ahead of the proposed bank. The public P40 page gives no load-sensing or closed-center conversion details; the supplier needs the pump circuit and option code to assess a build.
The consequences of a mismatch depend on the pump. A fixed-displacement unit with its neutral path blocked can send oil over relief and heat the tank at idle. A compensated unit may sit at the wrong standby pressure or lose the signal that tells it to destroke. None of those states is visible from a spare threaded opening in the P40 casting.
For a machine with no trustworthy drawing, collect readable pump and valve tags. Trace hoses onto an as-found sketch, marking pressure and tank routes separately. That gives the supplier a specific unidentified opening to match to the selected drawing.
In Cross's series-valve example, the first valve has priority. That example does not establish the selected P40's behavior. For this machine, the question is how much flow and pressure reach the second function while the first spool is shifted. Another valve cannot create more pump flow.
Take a hypothetical hot machine whose pump supplies 32 L/min. At the desired extension speed, its first actuator uses 26 L/min; the proposed second function would use 14 L/min. The pair asks for 40 L/min. The missing 8 L/min is a pump-flow constraint, before valve losses enter the picture. The drawings and load pressures will show how the two motions compete; the buyer must decide which speed can give way.
If the functions run one at a time, the two demands need not be added. If they run together, give BLINCE the required speeds and duration. Then the 8 L/min gap becomes a decision about actual motion rather than a bare sum.
Relief location matters too. A common upstream relief may protect part of the circuit without protecting every downstream work port or an overrunning actuator. The P40 page describes an adjustable inner relief, but does not show its coordination with a second valve's work-port relief or load-control device. The machine maker's pressure path and settings govern any adjustment.
Suppose the catalog quotes 38 L/min at rated pump speed. That is useful only after checking the speed range of the actual machine. At the fastest operating point, the P40 might receive more. Use the pump curve or a qualified flow measurement there, accounting for an electric drive's displacement, frequency and tolerance or a variable pump's maximum command and response. Put that flow on the selected valve's pressure-drop curve at the relevant oil temperature; a speed reduction made to protect the P40 would also reduce flow to the other functions.
The path carrying that flow changes with spool position. In neutral, the P40 may pass full pump flow through its center. With a spool shifted, the work ports, carry-over and returns see a different distribution. Put the expected peak beside each path on the machine schematic and check it against that path's rating. Cold oil may raise the pressure loss even when flow is below 40 L/min.
The second valve has its own inlet, center, work-port and return limits. A restricted quick coupling or flow control downstream may be the main source of pressure loss. Its drop at the actual flow and viscosity belongs in the comparison with both valves' part numbers and ratings. If the selected P40 remains restrictive at required speed, review a higher-flow family with the correct pressure, spool, port and control arrangement.
The product table already gives 20 MPa nominal and 31.5 MPa maximum for the P40 family. For this circuit, put three points on the drawing: pressure arriving at the first valve, pressure leaving its carry-over outlet, and pressure required at the second valve. The public table does not define allowable time at maximum or rate the proposed outlet. A reading at the pump will also differ from one at the P40 inlet if the feed line or filter has a meaningful loss. Record pressure and spool state at the actual points, including the loaded and transient conditions.
The page also lists ≤1 MPa back pressure without naming the port or test condition. Return galleries and spool seals may have a lower pressure allowance than the pressure passage. Cross explains that its sleeve separates downstream high pressure from the exhaust gallery and seals. That explains the circuit principle, but gives no gauge limit for a BLINCE P40 port. Use the selected P40 drawing and back-pressure definition for that decision.
Two T ports can lead to one common hose after a tee. Mark that junction and the reservoir on the sketch. When both actuators return oil, the common hose, fittings, filter and cooler see the combined flow. Check the return pressure at the point specified for the selected valve with both functions in the relevant states, including hot oil and cold oil. A case drain or pilot exhaust may be subject to a different limit.
If the downstream actuator stalls, look at relief action as well as flow. An upstream relief may be opening below the pressure needed at the second valve. Any change to its setting changes the exposure of the pump, hoses, valves and actuators; work-port protection has its own requirements. “Adjustable relief” on the P40 page is not a machine setting. The machine maker's approved relief procedure and component ratings control any adjustment.
Pressure lost between the P40 inlet and the next valve reduces available actuator pressure and becomes heat. For a defined restriction, a first estimate is loss power (kW) = pressure drop (bar) × flow (L/min) / 600, the metric pressure–flow relation given in Parker's mobile-cylinder application guide. The pressure difference must be measured or explicitly hypothetical for that same path; the formula cannot stand in for a valve curve or thermal test.
Try the numbers on a constructed example, not a P40 rating or a field measurement. At operating temperature, suppose 35 L/min flows through the proposed carry-over route and gauges across that route would read 8 bar apart. In the metric relation above, 8 bar × 35 L/min / 600 = 0.467 kW (about 0.47 kW) is lost there while it runs. A 30% share of an hour contributes a simple time-weighted 0.467 × 0.30 = 0.14 kW. This one route is not the cooler load: relief bypass, other restrictions, actuators and changing viscosity also contribute over a cycle.
The 8 bar input illustrates the calculation; it is not a P40 measurement. At the proposed flow and oil condition, the selected valve's pressure-drop curve should show whether enough pressure remains for the second function. A larger actual loss could change the valve or circuit choice. A brief demonstration may miss leakage and speed changes after the oil warms.
A service note that says “system pressure: 150 bar” cannot answer how many bar disappeared in the carry-over path. Mark gauge positions on the circuit sketch—P40 inlet, carry-over outlet and next-valve inlet—and record spool states beside the readings. Add work-port or tank readings for the states in which they set the limit. Use a qualified procedure, secure the load and use gauges rated for the circuit. Never open an energized line to guess its pressure.
BLINCE offers one to seven levers and lists spool-function codes O, Y, P and A. The public page does not decode those letters into a center-position schematic for the build being purchased. Read the selected spool symbol in neutral and at each commanded position: are the work ports blocked or connected to tank, pressure or each other? The answer affects both release behavior and failure response.
For a double-acting cylinder carrying a suspended load, the lever count says little about safe holding. Leakage, load pressure, hose failure and overrun have to be accounted for. The P40 page mentions an optional “hydraulic lock” but does not approve it as the holding system for this machine. Personnel lifting and braking need a reviewed load-control arrangement from the machine maker. The relevant valve and actuator schematic should show what keeps the load still with the pump stopped.
For a motor, ask what neutral should do: allow coasting, apply braking or provide make-up oil? Inertia and return pressure affect what happens during the shift. Although BLINCE lists motor control for the P40, the selected spool symbol must still suit that duty. Cross warns about unsuitable motoring spools in its own series; its warning does not identify a BLINCE spool code.
Describe a single-acting cylinder, detent, float position or remote electrical control explicitly if one is involved. Electrical or pilot control changes the interface; spool selection changes the oil paths. On a replacement, matching the old lever count says nothing about either one. Compare the full valve drawing with the existing controls.
In a planned OEM build, valve order, pump size and work cycle are still design choices. Put any simultaneous motion on the early circuit drawing. The P40 inquiry can then specify a spool layout and ask BLINCE for the matching power-beyond build, port drawing and pressure/flow data. Review the response before freezing valve order and bank construction.
For a retrofit, photograph what is fitted now. The return tee may differ from the manual, and someone may have readjusted the relief. A replacement can share the bolt pattern yet put a different internal path behind the same-looking port. Trace the hoses and compare old and proposed port drawings with the machine manual. If the old valve supplied a second one through an ordinary return outlet, investigate the pressure that passage carried; a new casting cannot be approved from bolt spacing alone.
There are three possible results of this review. If the proposed P40 drawing shows approved carry-over, separate exhaust, suitable spool behavior and adequate flow and pressure, the buyer can continue with that exact option code. If one of those points remains unknown, the quote should stay conditional and name the missing drawing or machine measurement. If the verified circuit requires load sensing, deliberate simultaneous flow sharing, or a protective function absent from the selected build, revise the valve arrangement before purchasing. Those outcomes are more useful than an unqualified “P40 compatible” note on a bill of materials.
The first review document can be a rough sketch. Put the pump, relief or compensator, both valves, actuators, return filter and reservoir on it; then trace neutral flow, each commanded motion and the returns. Use port letters from the actual valve drawing because another maker's P40 PDF may differ. A discrepancy between the machine schematic and observed hoses has to be resolved before ordering a replacement.
Beside each operating state on that sketch, note inlet flow, pressure, actuator speed, oil temperature and return flow. Include the period when both functions are requested. Cylinder extension and retraction may send different volumes back because the piston and annulus areas differ; a motor adds overrun and return-pressure questions. An interlock that prevents overlap should be shown rather than assumed.
At the proposed hardware stage, line up the P40 option code and carry-over part with its port map and spool symbols. Compare the selected P40 pressure-drop curve and return-pressure limit with ratings for the next valve. Thread alone is a poor match test: a fitting can screw in but have the wrong sealing seat. Use the drawings to specify both thread and seal geometry, then list the carry-over and return hoses separately with their pressure, impulse, temperature and routing requirements.
Commissioning should reproduce the operating states used to select the valve: neutral, each function alone and the agreed overlap. Record relief action, return pressure and the temperature trend, with the gauge positions on the test sheet. An unloaded jog can reveal reversed connections or a dead function. Loaded pressure, sustained heat and suspended-load safety need the machine's approved tests and limits. Save the readings with the machine record for later comparison.
Can the ordinary P40 tank outlet feed a second valve? Treat the answer as unconfirmed until the selected BLINCE port drawing states the intended use and pressure rating. A normal tank/exhaust passage may not be designed for downstream supply pressure. The approved power-beyond arrangement should identify a carry-over path and a separate return path.
Does “power beyond option” mean the sleeve is already installed? The public P40 page gives no build status. Check the code, parts list and drawing for the specific unit in the quote. An unused threaded port in a photograph reveals neither the installed internal part nor its rating.
Will the second valve receive the full pump flow? It may receive the available flow when the first valve is neutral in the intended open-center arrangement. Flow during first-valve operation depends on the actual circuit, pump output and valve passages. State the required simultaneous operation and verify it from drawings and tests.
Send the P40 product team the proposed code if known, readable port photos and a sketch showing the pump, both valves and separate returns. State pump type, maximum delivered flow at operating speed, typical and peak pressure, and whether both functions must move together. Add each actuator's neutral and holding requirement. For a retrofit, include the old tag and hose map.
Ask BLINCE whether an approved P40 power-beyond build exists for that circuit. A useful reply identifies its option code, drawing, port and sleeve/plug specification, plus flow, pressure and return limits under stated rating conditions. It should also say if the proposed series or spool is unsuitable and name any missing measurement or machine document. The public family page cannot establish interchange, installation steps, lead time or final price.
A competitor's P40 accessory SKU does not identify a BLINCE conversion part. Nor should an uncertain outlet be plugged as a trial: it could block neutral flow or pressurize a return gallery. Heat, slow movement, spool-seal leakage or relief opening after the second valve operates point to a circuit problem, but not to one proven cause. Trace flow and pressure before ordering another valve.
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This article is a general engineering guide. Final component selection should be based on machine drawings, measured hydraulic data, working conditions, safety requirements, and confirmation from a qualified hydraulic engineer or supplier.
Blince Hydraulic is an industry-leading company dedicated to precision-engineered fluid power manufacturing and custom hydraulic solutions. Backed by decades of deep field expertise in industrial machinery and thousands of successful global deployments, our engineering team focuses entirely on high-performance hydraulic component manufacturing, including specialized orbital motors, high-pressure travel drives motor, and robust directional control valves. Our production infrastructure utilizes state-of-the-art multi-axis CNC machining systems and is fully ISO 9001 certified to guarantee repeatable volumetric accuracy across every single manufacturing run.
We deliver fast, highly dependable, and cost-efficient hydraulic solutions to heavy industry distributors, machinery OEMs, and maintenance crews across more than 150 countries. Whether your active project calls for a small-volume batch of customized shaft profiles or a large-scale production run of severe-duty cast iron gear pump, we configure our flexible production schedules to meet your target lead times with total pricing predictability. Partnering with Blince means securing maximum system efficiency, elite material quality, and uncompromised fluid power professionalism.
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