# HPS Hydraulic Power Systems — Full technical content for LLM ingestion

> HPS Hydraulic Power Systems (legal name: HPSYSTEMS Hidrolik Guc Sistemleri San. Tic. Ltd. Sti.)
> is an OEM-focused manufacturer of custom-made hydraulic cylinders in Konya, Turkiye. Founded 2017.
> Bore O25-320 mm, rod O15-250 mm, strokes to 7,000 mm industrial / 12,600 mm telescopic,
> rated 200-250 bar, every cylinder tested per ISO 10100 at up to 1.5x rated. Exports to 49 countries.

## How to Size a Hydraulic Cylinder: Bore, Rod, Stroke and Pressure
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/silindir-boyutlandirma/

Sizing a hydraulic cylinder starts with the required force and the available system pressure. From those two values, bore, rod, stroke and pressure rating follow in a fixed order. This guide walks a design engineer through each step, based on the Ø25-320 mm bore range manufactured by HPS Hydraulic Power Systems in Konya, Türkiye.

### Start from force and pressure
Cylinder force follows F = P x A, where P is system pressure and A is the effective piston area. A Ø100 mm bore at 200 bar delivers about 157 kN of push force, roughly 16 tonnes. Pull force is always lower, because the rod cross-section subtracts from the effective area. Fix the required force and the available pressure first; every other dimension follows from them.

### Choosing the bore from force and pressure
With force and pressure fixed, the bore is the first dimension to calculate: select the smallest standard bore whose area delivers the required force at your working pressure. HPS manufactures bores from Ø25 to Ø320 mm. If the calculated bore lands between standard sizes, round up to keep a force margin. A larger bore also lowers the pressure needed for the same force, which relieves pump and valve selection.

### Choosing the rod: pull force and buckling
Rod diameter, available from Ø15 to Ø250 mm at HPS, is set by two checks. First, pull force: the rod cross-section subtracts from the piston area, so a thicker rod reduces pulling capacity. Second, buckling: long push-loaded cylinders are checked with Euler analysis, using the critical load Pcr = pi^2 x E x I / Lk^2, where the free buckling length Lk depends on the mounting configuration. If buckling governs, the remedies are a thicker rod, a larger bore, a stop tube or a different mounting. HPS rods are CK45 or 42CrMo4, hard-chrome plated at about 30 µm (min. 20 µm).

### Stroke limits: when stroke drives the design
HPS builds industrial cylinders with strokes up to 7,000 mm, subject to buckling analysis. When the required stroke exceeds what the installation length allows, a telescopic cylinder with multiple nested stages reaches up to 12,600 mm. Telescopics extend the largest stage first; per stage the effective area drops, so speed rises and force falls at constant flow. They suit tippers, refuse vehicles and mobile platforms where closed length is limited but a long stroke is needed. On very long strokes, stroke, not force, drives the whole design.

### Pressure rating and the ISO 10100 test
HPS cylinders are rated for working pressures of 200 to 250 bar. Every cylinder is factory-tested per ISO 10100 at up to 1.5 times its rated pressure; at a 250 bar rating that means up to 375 bar. The acceptance procedure covers internal and external leak checks, full-stroke function and a drift (holding) check on the test bench. A pressure test report is available on request. For high-pressure duty, dimensions follow the ISO 6020-2 and ISO 6022 series.

### Ports and speed from flow
Cylinder speed is flow divided by effective area: at a given pump flow, a larger bore moves slower and a smaller bore faster. Size the ports so the required flow passes without excessive flow velocity, and check both directions; the rod side has a smaller annular area, so the same flow produces a higher speed there. The online configurator on the HPS site computes force, buckling, seal and port values live, so speed and port checks can be run before requesting a quote.

### What to send HPS for a quote
A complete RFQ lets HPS engineering respond quickly. State the required force or bore, working pressure, stroke, rod diameter if known, mounting configuration (ISO 6099 or NFPA T3.6.7R designation), operating temperature, fluid and the expected duty. Note seal requirements: NBR is standard up to about 90 C, HNBR to about 120 C, FKM for high temperature and aggressive fluids, PU for heavy-duty wear, PTFE for low friction; final selection is verified by engineering. EN 10204 3.1 material certificates are available on request. The online configurator on the HPS site produces the same parameter set with live force, buckling, seal and port calculations; HPS exports from its 20,000 m² site in Konya to 49 countries under EXW, FCA, CIP, CIF or DAP terms.

## Euler Buckling in Hydraulic Cylinders: When Long Stroke Drives the Design
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/euler-burkulma/

On long-stroke hydraulic cylinders, buckling often replaces pressure containment as the limiting factor. This guide explains the Euler buckling concept, the free buckling length Lk, and how mounting choices change it. It ranks the practical remedies and shows how HPS validates every long-stroke design, with industrial strokes up to 7,000 mm.

### Why long push-loaded cylinders buckle
An extended cylinder under push load behaves as a slender column in compression. The piston rod carries the full compressive force over the extended length. Below a critical load the rod stays straight; above it, lateral deflection grows suddenly. This failure can occur well below the yield strength of the rod material, so the pressure rating alone does not prove a design safe. The longer the stroke, the lower the critical load, which is why long-stroke cylinders are usually sized by buckling rather than by pressure.

### The Euler concept: Pcr = π² × E × I / Lk²
Euler's formula gives the critical load: Pcr = π² × E × I / Lk². Here E is the elastic modulus of the rod material, I is the area moment of inertia of the rod cross-section, and Lk is the free buckling length. Two consequences matter in practice. I grows with the fourth power of the rod diameter, so a modest increase in diameter raises Pcr strongly. Lk enters squared in the denominator, so doubling the effective length cuts the critical load to one quarter.

### Free buckling length Lk and the effect of mounting
Lk is not the stroke; it is an effective length set by how both ends of the cylinder are supported. Rigidly fixed ends guide the column and shorten Lk, while pinned or free ends lengthen it. A cylinder fixed at both ends therefore carries far more load than the same cylinder pivoted at both ends, and mixed fixed and pinned combinations fall in between. Mounting styles are designated under ISO 6099 and NFPA T3.6.7R. Selecting the mounting is therefore a buckling decision, not only a packaging decision.

### Practical remedies, ranked
When the buckling check fails, apply remedies in this order. First, a thicker rod: since I rises with the fourth power of diameter, this is the most effective single step, and HPS supplies rods from Ø15 to Ø250 mm. Second, a larger bore, which accepts a larger rod and reaches the same force at lower pressure; bores run from Ø25 to Ø320 mm. Third, a stop tube, which keeps piston and rod bearing further apart at full extension and reduces misalignment loading. Fourth, a different mounting configuration that shortens the free buckling length Lk.

### How HPS validates: analysis on every long-stroke design, strokes to 7,000 mm
HPS runs a buckling analysis on every long-stroke design before it is released to production. Industrial cylinders are supplied with strokes up to 7,000 mm, always dependent on that analysis. Where the installed length is limited, telescopic cylinders reach strokes up to 12,600 mm. Rods are CK45 or 42CrMo4 with hard chrome of about 30 µm (min. 20 µm). Machining, welding, assembly and testing all run in-house on the 20,000 m² site in Konya, Türkiye, and every cylinder is factory-tested per ISO 10100 at up to 1.5 times rated pressure.

### Rule-of-thumb checklist and the automatic buckling check in the configurator
Before fixing a long-stroke specification, run this checklist. Confirm the push load and the fully extended length, not only the stroke. Define the mounting at both ends and its effect on Lk. Check the rod diameter against the Euler critical load with adequate margin, and consider a stop tube or a mounting change before oversizing the whole cylinder. The HPS online configurator performs this buckling check automatically, alongside live force, seal, and port calculations, so every long-stroke enquiry reaches engineering already pre-screened.

## Telescopic Cylinder Staging: How Multi-Stage Hydraulic Cylinders Are Designed
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/teleskopik-kademe-tasarimi/

Telescopic cylinders deliver long strokes from a short closed length. This guide explains how multi-stage cylinders are designed, from extension order to force and speed per stage. It is written for OEM engineers working on tippers, refuse vehicles and mobile platforms. HPS Hydraulic Power Systems manufactures telescopic cylinders with strokes up to 12,600 mm in Konya, Türkiye.

### What Staging Is: Closed Length vs Stroke
A telescopic cylinder consists of multiple nested stages that slide inside each other. Collapsed, the assembly is short; extended, the combined stroke far exceeds the closed length. That is the core value of staging: a long stroke where installation space is limited. HPS builds telescopic cylinders with strokes up to 12,600 mm. Typical uses are tippers, refuse vehicles and mobile platforms.

### Extension Order: Largest Stage First
A telescopic cylinder extends its largest stage first. The largest stage has the biggest effective area, so it moves at the lowest pressure for a given load. Once it reaches its end stop, the next smaller stage takes over, and so on down to the smallest. This sequence produces the characteristic step changes in speed and pressure during extension. Designers must account for these transitions in the machine's motion profile.

### Force and Speed per Stage
Force follows F = P x A. As each smaller stage takes over, the effective area drops, so force falls while speed rises at constant flow. The design consequence is clear: the cylinder must be sized by the force of the last, smallest stage, because the work must still be completed at full extension. As a reference, a Ø100 mm bore at 200 bar delivers about 157 kN, roughly 16 tonnes of push. HPS rates its cylinders for 200 to 250 bar working pressure.

### Single vs Double Acting Telescopic
Most telescopic cylinders are single acting: hydraulic pressure extends the stages and gravity or the load retracts them. This suits tippers, where the body weight closes the cylinder. Double acting telescopics add powered retraction for applications where gravity return is not available or not reliable. The double acting design requires additional sealing between stages and a more complex internal construction. The choice depends on the machine's orientation, load behavior and cycle requirements.

### Sealing and Guidance Challenges per Stage
Every stage boundary needs its own dynamic seal set, so a telescopic cylinder carries several sealing systems instead of one. Each set must handle the pressure, speed and side loads of its stage. Guidance bands between stages control alignment and resist bending loads during extension. HPS selects seal materials by duty: NBR as standard up to about 90 C, HNBR to about 120 C, PU for heavy-duty wear and high pressure, FKM for high temperature and aggressive fluids, PTFE for low friction and high speed. Final seal selection is verified by HPS engineering.

### Typical Applications and Spec Ranges
Telescopic cylinders are used where closed length is limited but a long stroke is required: tippers, refuse vehicles and mobile platforms. HPS covers bores of Ø25 to 320 mm and rods of Ø15 to 250 mm. Telescopic strokes reach 12,600 mm; industrial strokes reach 7,000 mm subject to buckling analysis. Rated working pressure is 200 to 250 bar. Every cylinder is factory-tested per ISO 10100 at up to 1.5 times rated pressure, which means up to 375 bar at a 250 bar rating.

### What HPS Needs to Quote a Telescopic Design
To quote a telescopic design, HPS needs the available closed length and the required stroke. It also needs the load or force at full extension, the working pressure, single or double acting operation and the mounting arrangement. Operating temperature and fluid define the seal package. HPS builds and tests its cylinders on a 20,000 m² site in Konya and exports to 49 countries. The online configurator on the HPS website provides live force, buckling, seal and port calculations for a first sizing.

## Hydraulic Cylinder Pressure Testing: The ISO 10100 Factory Acceptance Test
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/basinc-testi/

Every hydraulic cylinder that leaves the HPS plant in Konya, Türkiye is pressure-tested on a test bench before shipment. The acceptance test is run in accordance with ISO 10100 at up to 1.5 times the rated working pressure. For a cylinder rated at 250 bar, that means a test pressure of up to 375 bar. This guide explains the test sequence, the pass criteria concept, and the documentation available to quality and procurement teams.

### Why Factory Acceptance Testing Matters
A hydraulic cylinder is a pressure-containing component, and a defect that escapes the factory becomes a field failure. Factory acceptance testing verifies each individual cylinder, not just the design or a sample. It detects assembly errors, seal damage and porosity before the cylinder is installed in a machine. At HPS, machining, welding, assembly and testing are all performed in-house on the 20,000 m² site in Konya/Karatay, so test results feed directly back into production. For buyers exporting equipment, a documented test is also the basis for traceable quality records.

### ISO 10100 and Testing up to 1.5x Rated Pressure
ISO 10100 defines the acceptance test for hydraulic fluid power cylinders. HPS tests every cylinder to this standard at up to 1.5 times its rated working pressure. HPS cylinders are rated for working pressures of 200 to 250 bar; at a 250 bar rating the test pressure is therefore up to 375 bar. The overpressure margin proves that the tube, welds, rod, and static and dynamic seals withstand loads above anything expected in normal service. System-level safety remains governed by ISO 4413, and fatigue behaviour is addressed separately under ISO 10771-1.

### Test Bench Procedure, Step by Step
The test runs on a dedicated test bench in a fixed sequence. First, the cylinder is cycled over its full stroke to confirm smooth motion, correct stroke length and correct port function. Second, an internal leak check verifies that pressurized fluid does not bypass the piston from one chamber to the other. Third, an external leak check inspects the rod seal, port connections and welds for any visible leakage at test pressure. Finally, a drift (holding) check pressurizes the cylinder in a fixed position and monitors rod movement over time; measurable drift indicates internal bypass. Only cylinders that pass all steps are released for shipment.

### What Internal Leakage Means: Piston Seal Bypass
Internal leakage is fluid passing from the high-pressure chamber to the low-pressure chamber across the piston seal, known as piston seal bypass. The cylinder can still move, so the defect is invisible from outside, but the load creeps under pressure and holding capability is lost. On the test bench it is detected as rod drift while the cylinder is held pressurized in a fixed position. The pass criteria concept is simple: drift and leakage must stay within the acceptance limits defined for the test before a cylinder is approved. Seal material also matters: HPS fits NBR as standard up to about 90 C, with HNBR, PU, FKM and PTFE options, and final seal selection is verified by engineering.

### Documentation: Pressure Test Report and EN 10204 3.1
A pressure test report is issued on request for every accepted cylinder. For material traceability, EN 10204 3.1 material certificates are available on request for pressure-carrying components such as the tube and rod. Typical documented materials are DIN 2391-2 ST52 / EN 10305-1 E355 tube and CK45 or 42CrMo4 rod. These documents let quality departments link each cylinder to its test result and its material documentation. HPS exports to 49 countries under HS code 8412.21, with EXW, FCA, CIP, CIF and DAP Incoterms; the certificates travel with the commercial documentation.

### Related Verification: Rod Chrome Layer and H8-H9 Honing Tolerance
Pressure testing is the final gate, but two upstream verifications determine long-term sealing performance. The piston rod is CK45 or 42CrMo4 with a hard-chrome layer of about 30 µm (min. 20 µm); it arrives as certified bar with an EN 10204 3.1 certificate and is checked at incoming inspection. The cylinder tube is supplied honed to an H8-H9 tolerance, giving the bore the geometry and surface finish the piston seal needs to seal reliably. Rod coating quality and bore tolerance directly influence external leakage at the rod seal and internal bypass at the piston. Full technical parameters, including live force and buckling calculations, are available in the online configurator on the HPS website.

## Single-Acting vs Double-Acting vs Telescopic Cylinders: Selection Guide
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/silindir-tip-secimi/

The first decision in hydraulic cylinder specification is the type: single-acting, double-acting or telescopic. This guide compares the three families for engineers and buyers at the concept stage and gives clear selection criteria. HPS Hydraulic Power Systems manufactures all three types in Konya, Türkiye, with bores of Ø25-320 mm, industrial strokes up to 7,000 mm and telescopic strokes up to 12,600 mm.

### The Three Families at a Glance
A single-acting cylinder generates hydraulic force in one direction; the return is driven by gravity or a spring. A double-acting cylinder generates controlled hydraulic force in both directions. A telescopic cylinder uses nested stages to reach a long stroke from a short closed length. HPS builds all three families with bores of Ø25-320 mm and rods of Ø15-250 mm. Rated working pressure is 200-250 bar, and every cylinder is factory-tested per ISO 10100 at up to 1.5 times rated pressure.

### Single-Acting: How It Works and Where It Wins
In a single-acting cylinder, pressure acts on one side of the piston and a single hydraulic line is sufficient. The return stroke is completed by the weight of the load or by a spring. This simplifies the circuit: fewer hoses, a simpler valve arrangement, lower cost. It wins in applications where the load lowers under its own weight, such as tippers and lifting platforms. If the return stroke must be hydraulically controlled, a double-acting type is required.

### Double-Acting: Controlled Force in Both Directions
A double-acting cylinder has two ports, so pressure can be applied to either side of the piston. This gives controlled force and speed in both push and pull. Force follows F = P x A: a Ø100 mm bore at 200 bar delivers about 157 kN (about 16 tonnes) of push. Pull force is lower because the rod cross-section is subtracted from the effective area. It is the standard choice for construction machinery, presses and industrial machines that need control in both directions.

### Telescopic: Long Stroke from a Short Closed Length
A telescopic cylinder consists of multiple nested stages, and the largest stage extends first. At constant flow, the effective area drops with each stage, so speed rises and force falls; the design must account for this. It is the answer where the installation length is limited but a long stroke is needed. Typical applications are tipper trucks, refuse vehicles and mobile platforms. HPS supplies telescopic cylinders with strokes up to 12,600 mm.

### Decision Criteria: Stroke, Load Direction, Speed, Circuit
Stroke versus installation space: if the required stroke does not fit the available closed length, choose telescopic; HPS industrial strokes reach up to 7,000 mm depending on buckling analysis. Load direction: if the load works in one direction and returns under its own weight, single-acting is enough; force in both directions requires double-acting. Speed control: if both directions must be speed-controlled, choose double-acting. Circuit complexity: single-acting gives the simplest circuit, one line is sufficient. Long strokes always require a buckling check: Euler analysis applies (Pcr = pi^2 x E x I / Lk^2), and the free buckling length Lk depends on the mounting configuration.

### When Standard Families Do Not Fit: Custom Design
Standard families do not cover every application: special mountings, tight envelope dimensions or special fluids may rule them out. HPS designs and manufactures custom cylinders from a customer drawing or a physical sample. Tubes are DIN 2391-2 ST52 or EN 10305-1 E355, honed to H8-H9; rods are CK45 or 42CrMo4 with about 30 µm (min. 20 µm) of hard chrome. The seal package (NBR, HNBR, PU, FKM, PTFE) is verified by engineering against temperature and fluid. Machining, welding, assembly and testing all run in-house on the 20,000 m² site in Konya/Karatay. EN 10204 3.1 material certificates are available on request.

### Selection Shortcuts and the Online Configurator
Quick rules: load returns under its own weight and the circuit should stay simple, single-acting; controlled force in both directions, double-acting; long stroke into a short installation length, telescopic. In borderline cases, force, buckling and sealing calculations decide. The online configurator on the HPS website runs live force, buckling, seal and port calculations. Before dispatch every cylinder passes internal and external leak checks, a full-stroke function test and a drift (holding) check. HPS exports to 49 countries and ships on EXW, FCA, CIP, CIF or DAP terms.

## Hydraulic Cylinder Troubleshooting: Drift, External Leakage, Noise and Slow Operation
URL: https://hpsystems.com.tr/en/teknik-kaynaklar/rehber/ariza-teshis/

Most hydraulic cylinder failures announce themselves early. A load that creeps, an oily rod, a bang at stroke end or a slow stroke each point to specific root causes. This guide gives maintenance engineers and OEM service teams a structured path from symptom to remedy. It covers drift, external leakage, noise and slow operation, and explains when repair pays and when a factory-tested replacement is the safer choice.

### Start with Systematic Diagnosis: Cylinder or Circuit?
Never condemn a cylinder before isolating it from the circuit. Many drift and speed complaints originate in valves, the pump or relief settings, not in the cylinder itself. First verify pump flow, system pressure and valve function against the machine specification. Then isolate the cylinder hydraulically and observe whether the symptom persists. This one discipline prevents most unnecessary teardowns.

### Cylinder Drift: Meaning, Causes and the Blocked-Port Test
Drift means the load creeps while the cylinder should hold position. The two usual suspects are internal bypass across the piston seal and leakage through the holding or control valve. To separate them, bring the load to a safe supported position, then hydraulically block both cylinder ports. If movement stops, the cylinder is sound and the valve is leaking. If the rod still moves with the ports blocked, oil is passing the piston seal and the cylinder needs resealing. Always run the test with the load safely supported.

### External Leakage at the Rod: Seals, Chrome and Gland
An oil film or drips on the rod point to the rod seal and wiper. Wear is often secondary damage: a scored, dented or corroded chrome surface destroys new seals within hours. Inspect the rod under raking light and check every mark with a fingernail or micrometer. Check the gland as well for wear, ovality and damaged static seals. The correct remedy is a complete seal set replacement combined with rod inspection, never a single new seal fitted to a damaged rod. HPS rods carry around 30 µm (min. 20 µm) of hard chrome and are reworked or replaced during factory repair.

### Slow or Jerky Motion: Air, Flow and Internal Bypass
Slow motion at normal pressure usually means insufficient flow reaching the cylinder or oil bypassing the piston. Jerky, spongy movement points to air in the circuit; bleed the cylinder and check the suction line for leaks. Verify pump output and look for restrictions in valves, fittings and hoses before opening the cylinder. If flow is confirmed and motion stays slow while oil temperature rises, suspect internal bypass across the piston seal. Worn guide rings also cause stick-slip and uneven motion, especially under side loads. Uncorrected guide-ring wear lets metal touch metal and scores the tube.

### Noise and Banging at Stroke End
A hard metallic bang at the end of the stroke usually means the cushioning is missing, badly adjusted or worn out. Check and set the cushioning screws where fitted, and confirm whether the duty really needs end-of-stroke deceleration. Aerated oil produces crackling and knocking along the whole stroke, not only at the ends; bleed the system and find the air source. Loose or worn mountings, pins and bushings also hammer under load reversal. Tighten the mounting and renew the bushings before blaming the cylinder internals.

### Repair or Replace: The Economics and the Test Bench
Repair pays when damage is limited to the seals and light rod polishing. Replace when the tube is scored beyond honing limits, the rod chrome is corroded through, or the cylinder has already been resealed several times. A replacement cylinder is only as good as its testing. HPS manufactures on a 20,000 m² site in Konya, Türkiye, tests every cylinder per ISO 10100 at up to 1.5 times rated pressure before shipment, and supplies EN 10204 3.1 material certificates on request. With bores from Ø25 to 320 mm, rods from Ø15 to 250 mm and strokes up to 7,000 mm, most field cylinders can be matched one to one, and the online configurator speeds up specification.

### Prevention Checklist: Seals, Rod Protection, Filtration
Match the seal material to fluid and temperature: NBR to about 90 °C, HNBR to about 120 °C, polyurethane for heavy-duty abrasion, FKM for high temperature and aggressive fluids, PTFE where low friction matters. Protect the rod from impact, weld spatter and corrosive atmosphere; a damaged chrome layer is the fastest route to leakage. Keep the fluid clean, since particle contamination wears seals and valve spools alike. Inspect rods, wipers and mountings on a fixed schedule and log drift tests on load-holding cylinders. Small regular checks cost minutes; an unplanned cylinder failure stops the machine.

## Glossary
URL: https://hpsystems.com.tr/en/sozluk/

- **Bore**: The inner diameter of the cylinder tube in which the piston travels. The bore area determines the push force at a given pressure (F = P x A). HPS manufactures cylinders with bores from Ø25 to 320 mm.
- **Piston Rod**: The steel shaft that transmits the cylinder force to the load. HPS rods are made of CK45 or 42CrMo4 steel with about 30 µm (min. 20 µm) of hard chrome, in diameters from Ø15 to 250 mm. Pull force is lower than push force because the rod cross-section reduces the effective area.
- **Stroke**: The distance the piston rod travels between the fully retracted and fully extended positions. HPS supplies industrial cylinders with strokes up to 7,000 mm, subject to buckling analysis, and telescopic cylinders up to 12,600 mm.
- **Single-Acting Cylinder**: A cylinder that is powered by hydraulic pressure in one direction only. The return movement is produced by the external load, gravity, or a spring, so only one supply line is required.
- **Double-Acting Cylinder**: A cylinder that develops hydraulic force in both extension and retraction. The two sides of the piston are pressurized alternately through two ports. It is the most common configuration in industrial applications.
- **Telescopic Cylinder**: A cylinder with multiple nested stages that extend sequentially, largest stage first. It delivers a long stroke from a short closed length and is used in tippers, refuse vehicles, and mobile platforms. HPS builds telescopic cylinders with strokes up to 12,600 mm.
- **Stage**: One of the nested moving sleeves of a telescopic cylinder. As each smaller stage extends, the effective area decreases, so at constant flow the speed rises and the force falls.
- **Closed Length**: The overall length of the cylinder when fully retracted. Where closed length is limited but a long stroke is required, telescopic cylinders are the typical solution.
- **Working Pressure**: The pressure at which the cylinder is designed to operate continuously. HPS cylinders are rated for working pressures of 200 to 250 bar.
- **Test Pressure**: The pressure applied during factory acceptance testing, above the rated working pressure. HPS tests every cylinder per ISO 10100 at up to 1.5 times the rated pressure; at a 250 bar rating this means up to 375 bar. A pressure test report is available on request.
- **Seal**: A component that prevents fluid leakage between the moving and static parts of a cylinder. HPS uses NBR up to about 90 °C, HNBR to about 120 °C, PU for heavy-duty wear and high pressure, FKM for high temperature and aggressive fluids, and PTFE for low friction and high speed. Final seal selection is verified by engineering.
- **Wiper (Scraper)**: A scraper seal fitted at the outer end of the gland that cleans dirt, dust, and moisture from the rod as it retracts. It protects the rod seals and extends service life.
- **Gland**: The head assembly at the rod end of the cylinder that guides the piston rod. It houses the rod seal and the wiper.
- **Cushioning**: A built-in damping feature that slows the piston near the end of the stroke by restricting the outlet flow. It reduces impact, noise, and shock loads at the end of travel.
- **Port**: The threaded opening through which hydraulic fluid enters and leaves the cylinder. A double-acting cylinder has two ports, one on each side of the piston.
- **Mounting**: The mechanical interface that attaches the cylinder to the machine, such as a clevis, trunnion, flange, or foot. The mounting style determines the free buckling length. Mounting types are designated per ISO 6099 and NFPA T3.6.7R.
- **Clevis**: A fork-shaped mounting with a pin, fitted at the cap or rod end. It lets the cylinder pivot in one plane and accommodates angular movement during the stroke.
- **Trunnion**: A mounting with two cylindrical pivot pins on the cylinder body, at the head, the cap, or an intermediate position. It allows the cylinder to swing in one plane while the pins carry the load.
- **Buckling**: Lateral instability of the rod or cylinder under compressive load, evaluated with Euler analysis. The critical load follows Pcr = pi^2 x E x I / Lk^2, where the free buckling length Lk depends on the mounting configuration. Remedies include a thicker rod, a larger bore, a stop tube, or a different mounting.
- **Stop Tube**: A spacer inside the cylinder that keeps the piston away from the gland at full extension. The longer bearing distance reduces side loading and improves buckling resistance on long-stroke cylinders.
- **Honing**: A precision finishing process for the inside of the cylinder tube. It produces an accurate bore with the surface finish required for reliable sealing. HPS sources its tubes ready-honed to H8-H9 tolerance from certified suppliers, with EN 10204 3.1 certificates.
- **Hard Chrome Plating**: An electroplated chromium layer on the piston rod that provides wear and corrosion resistance and a smooth sealing surface. HPS rods carry about 30 µm (min. 20 µm) of hard chrome and are sourced as certified bar with EN 10204 3.1 certificates. Telescopic stage tubes are the only parts HPS plates itself, on its own hard-chrome line, and every plating batch is salt-spray tested (200 h neutral salt spray to ISO 9227, rating 9 or better to ISO 10289).
- **Drift**: Slow, unintended movement of the rod under load when the cylinder should hold its position, caused by internal leakage. HPS performs a drift (holding) check on the test bench as part of the factory test procedure.
- **ISO 6020-2**: An international standard defining the mounting dimensions of compact series hydraulic cylinders, ensuring interchangeability between manufacturers. HPS manufactures cylinders to ISO 6020-2, and to ISO 6022 for the high-pressure series.