Understanding Filtration – Fluid Cleanliness & Filter Efficiency

Understanding Filtration – Fluid Cleanliness & Filter Efficiency

In part 1 of this series on Understanding Filtration – Viscosity and Temperature we covered the significant impact that temperature has on the viscosity of an oil, which in turn affects its performance during filtration and lubrication.

There are other factors that must be taken into account when it come to hydraulic filter selection.

These variables will affect each other. To select the correct filter you need to establish the expected fluid viscosity as it varies with temperature.

The following must be known:

  • The fluid type
  • The fluid temperature at start up
  • The fluid temperature during normal operation

Other important factors are:

  • The required fluid cleanliness target
  • The efficiency rating of the filter

Fluid Cleanliness Targets

When discussing fluid cleanliness, we refer to ISO 4406 as a method of counting and quantifying contamination in a system.

Hydraulic Filters - Cleanliness Codes

The chart above shows recommended ratings for common system components. Many hydraulic manufacturers publish required fluid cleanliness levels for their equipment.

Guide to Filter Placement

The table below can be used as a guide for filter placement in a system.

Each of the blocks shows the suggested micron rating for the filter element. Note that RYCO support suction and return filters only.

Hydraulic Filters - Placement Guide

The method for selecting the filter type is to check the published minimum cleanliness level for the most sensitive component in the system, and then looking at the chart to select the filter rating and placement required.

Beta Ratios and Filter Efficiency

When choosing filtration products, it is important to understand how well the product will perform.

ISO 4572 is known as a multipass test. It measures the filtering efficiency of the element, which is published as the Beta ratio.

Hydraulic Filters - Multipass Test

The multipass test also establishes the pressure drop across a filter element, and the dirt holding capacity of the element.

The Beta ratio is the ratio between the number of particles introduced to a fluid before a filter, and the number of particles after the fluid has passed through a filter element.

The Beta ratio is displayed with a micron rating. In this way the ratio describes the filtering efficiency of the filter element when trapping particles of a given size.

Hydraulic Filters - 5 Micron Beta Ratio Calculation

A filter that is a poor performer at trapping particles will have a lower Beta ratio than a more efficient filter.

Filters with a low Beta ratio are called NOMINAL filters, as they have a NOMINAL rating. This means that the filter will be adequate at trapping particles of a given size.

Hydraulic Filters - Beta Ratio Example Calculation

Filters that are highly efficient will have a higher Beta ratio. Filters with a Beta ratio over 75 are called ABSOLUTE rated filters. This means that they can be considered to trap all particles of a given size or larger.

This chart below also appears on page 381 of the RYCO Product Technical Manual, (AUS July 2007).

Hydraulic Filters - Multi-Pass Test Results

It demonstrates that a 10 micron absolute filter is very efficient at trapping particles larger than 10 micron, but ineffective at trapping smaller particles.

Filter Bypass

Almost all filter elements are supported on the inside surface. Fluid flows through the element from the outside to the inside.

Hydraulic Filters - Cutaway

As a filter catches and holds particles, it gets harder for fluid to flow through the element.

Hydraulic Filters - Element Flow

This causes a build up of pressure on the outside of the element, therefore a pressure differential across it.

If too high a pressure is allowed to build up inside a filter housing, it could cause the element to collapse, or the housing to rupture.

Many filters incorporate a bypass valve, which limits the pressure differential by allowing the fluid to bypass the element.

Hydraulic Filters - Bypass Valve

During the bypass condition, there is no filtering taking place.

Hydraulic Filters - Bypass Filtering

It is important to remember that filter bypass is not a desirable condition.

Hydraulic Filters - Filtering vs Bypassing

A rule of thumb for system designers and selectors of filtration products is that the pressure drop across a new or “clean” element should not exceed 25% of the bypass rating. i.e. 2.5 Bar pressure drop allowed for a 10 Bar bypass spring rating.

Indicators are fitted to filters to display the pressure drop across the element.

Hydraulic Filters - Pressure Drop Indicators

It is strongly recommended that all filters have condition indicators fitted.

For more information, see page 370 of the RYCO Product Technical Manual (RHY-RHC0707AUS).

Understanding Hydraulic Filtration

In simple terms, filtration is a method of removing particles from a fluid by trapping them within a screen of suitable material.

Hydraulic Filters - Filter Products

Filtration becomes more complex when you look more closely at it.

Fluid type, temperature, operating temperature, filter efficiency and by-pass settings all influence the effectiveness of any filtration product.

Please also read the (yellow) filters section of the RYCO Product Technical Manual to understand hydraulic filtration in even more detail.

Want more information?

Read more about effective filtration of hydraulic systems in part 1 of this series on Understanding Filtration – Viscosity and Temperature.

And to help you choose the right hydraulic hose for your project, download our 15 Keys To Selecting The Right Hose guide now.

Understanding Filtration – Temperature and Viscosity

Understanding Filtration – Temperature and Viscosity

Understanding Filtration in Hydraulic Systems

When adding filtration to an hydraulic system, it’s important to understand the role of viscosity, pressure drop, fluid cleanliness and filter efficiency (beta ratios) in the overall performance of the system.

Temperature is also a key factor in determining the effectiveness of hydraulic filters.

What is Viscosity?

Viscosity is the measure of the resistance of a fluid to deform under sheer stress.

It is commonly perceived as thickness, or as a resistance to pouring. It may also be described as a fluid’s resistance to flow, or a measure of fluid friction.

Water has a low viscosity, and honey has a high viscosity.

Hydraulic Filters - Viscosity

However, viscosity can be affected by changes in the fluid temperature. For example, when heated, honey will flow more easily.

Understanding the behaviour of a fluid’s viscosity is an important part of understanding filtration technology.

Pressure Drop

Pressure drop is a measure of how much pressure is required to push a fluid through a restriction, or ‘orifice’.

A filter element acts as a restriction when fluid is flowing through it. The level of restriction is a product of the fluid flow, fluid viscosity and the element rating.

Hydraulic Filters - Pressure Drop Across A Filter

A restriction to flow will cause a higher pressure before the element, and a lower pressure after the element, i.e. a pressure drop.

Fluid viscosity changes with fluid temperature. Oil becomes less viscous, i.e. thinner at higher temperatures, which affects the pressure drop.

Pressure Drop Flow Graphs For Filters

Refer to the RYCO Product Technical Manual for more details.

Hydraulic Filters - Pressure Drop Chart - RIF 10

These graphs show how the pressure drop across a filter is expected to rise as flow increases.

Hydraulic Filters - Pressure Drop Chart - RIF 12

While these graphs show vital information, the user must be aware that there is another variable that must be taken into account before these charts are used: temperature.

Temperature will have a dramatic effect on the oil viscosity, which in turn will change the expected pressure drop across the element.

The Effect of Temperature on Hydraulic Filter Performance

The selection of a hydraulic filter is more complex than that of selecting hoses, couplings or adaptors.

System parameters must be understood before the selection process can begin.

Factors such as fluid type, temperature, start-up conditions and the desired filtration outcomes must be considered.

Firstly, we need to more closely examine the effects that temperature will have on mineral oil.

Viscosity Calculation

This chart can also be found in the RYCO Product Technical Manual.

Hydraulic Filters - Pressure Drop Chart Example

It is entitled “Effect of temperature and viscosity on flow rate and pressure drop”.

It is used to calculate the expected viscosity for mineral type hydraulic oil as temperatures vary.

ISO Ratings for Hydraulic Oil

The ISO rating given to a hydraulic oil is based on the kinematic viscosity of the fluid at 40 degrees celsius.

This is ISO 3104: 1994 – “Determination of kinematic viscosity and calculation of dynamic viscosity”.

  • The kinematic viscosity is the relationship between viscous and inertial forces in a fluid.
    Dynamic viscosity is the relationship between the shear stress and the shear rate in a fluid.
    A centistoke (cSt) is the derived centimeter-gram-second (CGS) unit of kinematic viscosity.


Hydraulic Filters - Pressure Drop Chart Calculation - ISO 3104

This rating is based on the viscosity of the fluid at 40 degrees celsius.

For example, ISO 60 fluid will be 60 centistokes (cSt) at 40 degrees celsius.

Hydraulic Filters - Pressure Drop Chart Calculation - ISO 3104 40 degrees

ISO 32 fluid will be 32 centistokes (cSt) at 40 degrees celsius.

ISO 32 fluid will be 178 centistokes (cSt) at 10 degrees celsius.

Hydraulic Filters - Pressure Drop Chart Calculation - ISO 3104 10 degrees (cold)

For this reason, it is vital to consider the “cold start” condition of a hydraulic machine. i.e. What will the viscosity be at start up on a cold day?

ISO 32 fluid will be just over 11 centistokes (cSt) at 70 degrees celsius.

Hydraulic Filters - Pressure Drop Chart Calculation - ISO 3104 70 degrees (hot)

It is important to note that hydraulic fluid will lose lubricity if allowed to become too thin. This is dangerous.

The chart demonstrates the massive effect that temperature will have on the viscosity of an oil.

Want more information?

Read more about effective filtration of hydraulic systems in part 2 of this series on Understanding Filtration – Fluid Cleanliness & Filter Efficiency.

And download our 15 Keys To Selecting The Right Hose guide today and make sure you select the right hydraulic hose for your next project.

Who are the Type Approval Surveyors For RYCO’s products?

Who are the Type Approval Surveyors For RYCO’s products?

Approval bodies (Surveyors)

RYCO works with a number of approval bodies, or surveyors, to obtain type approvals for RYCO hydraulic hose assemblies, and maintain best practice quality management system standards.

Following is information about the surveyors who are currently providing type approval for RYCO products, using their own words.

Marine Approval Bodies

American Bureau of Shipping

ABS LogoMission Statement from the ABS website:

“The mission of ABS is to serve the public interest as well as the needs of our clients by promoting the security of life, property and the natural environment primarily through the development and verification of standards for the design, construction and operational maintenance of marine-related facilities.”


DNV-GL logoStatement from the DNV GL website:

“DNV GL’s shared roots stretch back to 1864, when Det Norske Veritas (DNV) was founded as a membership organisation in Oslo and GL was formed out of a desire to achieve transparency. Today DNV GL is a globally leading quality assurance and risk management company. Driven by their purpose of safeguarding life, property and the environment, DNV-GL enables organisations to advance the safety and sustainability of their business.”

Korean Register of Shipping

Korean Register LogoStatement from the KR website:

“Promoting technologies related to ships, land & offshore facilities, Enhancing safety of life and property, and protecting environment”

Lloyd’s Register

Lloyds Register LogoMission Statement from the LR website:

“We provide independent assurance to companies operating high-risk, capital-intensive assets in the energy and transportation sectors, to enhance the safety of life, property and the environment. This helps our clients to create safe, responsible and sustainable supply chains.”

Marine Equipment Directive

MED logoStatement from the MED website:

“The European Union has developed original and innovative instruments to remove the barriers to free circulation of goods. The mechanisms in place to achieve this aim are based on prevention of new barriers to trade, mutual recognition and technical harmonisation. Among these, the new approach to product regulation and the global approach to conformity assessment take pride of place.”

This group is sometimes called MED, sometimes MarED. Approved hose assemblies display a ships wheel symbol.

The number on the hose next to the wheel is the code of the listing agency, in this case DNV. The numbers after the slash are the batch code; a record of the production date.

The Royal Institution of Naval Architects

Royal Institute of Naval Architects LogoStatement from the RINA website:

“The Royal Institution of Naval Architects is a world renowned and highly respected international professional institution and learned society whose members are involved at all levels in the design, construction, maintenance and operation of all marine vessels and structures. ”

United States Coast Guard

United States Coast Guard logoStatement from the USCG website:

“For over two centuries the U.S. Coast Guard has safeguarded our Nation’s maritime interests in the heartland, in the ports, at sea, and around the globe. We protect the maritime economy and the environment, we defend our maritime borders, and we save those in peril. This history has forged our character and purpose as America’s Maritime Guardian —Always Ready for all hazards and all threats.”

Vehicle Approval Body

United States Department of Transportation

US Department of Transportation LogoStatement from the DOT website:

“To serve the United States by ensuring a fast, safe, efficient, accessible and convenient transportation system that meets our vital national interests and enhances the quality of life of the American people, today and into the future. ”

The United States Department of Transportation assesses and approves our “Automotive” hoses, T5 and RQP5. These hoses are often used on trucks.

Other Approval Bodies

Australian Gas Association

Australian Gas Association logoStatement from the AGA website:

“To provide high quality competitive certification services to industry and regulatory authorities and contribute to the safety, reliability and energy efficiency of gas and related products sold to Australian & international consumers.”

Australia – Mechanical Design Guidelines

Statement from the MDG 41 website:

“Over the past few years there has been an increase in fluid injection injuries from the use of pressurised fluid power systems. Pressurised fluid power systems are a potential major hazard which may result in fatal injuries if uncontrolled. This Guideline for Fluid Power System Safety at Mines has been compiled to assist in formulating a management system approach for the safe use of fluid power systems in mines. It should be used by designers, manufacturers, purchasers, owners, operators, site contractors and Industry & Investment NSW Mine Safety Operations when assessing the safety aspects of fluid power systems.”

British Standards Institution

British Standards Institute logoStatement from the BSI website:

“BSI is the business standards company that helps organizations all over the world make excellence a habit. For more than a century we have been challenging mediocrity and complacency to help embed excellence into the way people and products work. ”

Bureau Veritas

Bureau Veritas logoStatement from the BV website:

“To deliver economic value to customers through Quality, Health, Safety, Environment and Social Responsibility management of their assets, projects, products and systems, resulting in licence to operate risk reduction and performance improvement.”

China Classification Society

China Classification Society logoStatement from the CCS website:

“By committing to the mission of “safety, environmental protection and creating value for clients and society” and based on the 90 offices established across the globe, CCS provides services for a range of industry and fields, and is constantly developing new business areas.”


ClassNK LogoStatement from the ClassNK website:

“Since its inception in 1899, ClassNK has been engaged in a range of activities dedicated to ensuring the safety of life and property at sea and protecting the marine environment over the course of its 116 year history as a leading classification society.

ClassNK will use its expertise and practical experience accumulated over many years to continue contributing to the long-term development of the maritime cluster.”

National Association of Hose and Accessories Distributors (USA)

NAHAD member logoStatement from the NAHAD website:

“Professionalism and integrity within the hose and hose accessory industry. A community of communication, education and training dedicated to maximizing quality and enhancing profitability.”

National Fluid Power Association (USA)

NFPA logoStatement from the NFPA website:

“Our success depends on the active involvement of our stakeholders from across the supply chain—both in developing new programs and participating in those that provide the greatest benefits to their organizations, including manufacturers, distributors, suppliers, educators and customers.”

Quality & Safety Declaration of Conformity

GOST R LogoStatement from the GOST-R website:

“CCIS-Expertise is an international audit and advisory company, its activity is organized around three main areas of expertise: marketing of products, regulatory monitoring and industrial commissioning in Russia, in CIS countries and more recently in the EEU (Eurasian Economic Union).”

Rubber Manufacturers Association / U.S. Tire Manufacturers Association

Rubber Manufacturers Association logoStatement from the RMA website:

“To strengthen the reputation and competitiveness of the U.S. tire manufacturing industry. To be the premier advocate, trusted voice, and thought leader for the U.S. tire manufacturing industry. Advancing safe, sustainable mobility for the future.”

SAE International

SAE International logoStatement from the SAE website:

“To advance mobility knowledge and solutions for the benefit of humanity. SAE is the leader in connecting and educating mobility professionals to enable safe, clean, and accessible mobility solutions.”

State Administration of Work Safety (MAKA)

Maka LogoStatement from the MAKA website:

To organize, guide and supervise, in accordance with the law, the assessment of workers from specially identified industries (excluding the operators of special equipment), and the safety qualifications of chief administrators and safety supervisors of enterprises;

U.S. Department of Labor, Mine Safety and Health Administration

US MSHA logoStatement from the MSHA website:

“The U.S. Department of Labor’s Mine Safety and Health Administration (MSHA) works to prevent death, illness, and injury from mining and promote safe and healthful workplaces for U.S. miners.”

The Importance of Type Approval Surveyors

Each of these type approval bodies plays an important role in ensuring that all of RYCO’s hydraulic products comply with the relevant regulatory, technical and safety requirements.

Our rigorous and continual testing of our products ensures that not only do they meet the necessary standards, but generally exceed them.

To ensure the safety of your business and its employees, you’ll want to choose products with proven performance, that have been independently assessed and type approved by multiple parties, as is the case with all RYCO products.

Want more information?

Make sure you select the right hydraulic hose for your next project.Download our 15 Keys To Selecting The Right Hose guide today.

Type approvals for hydraulic hoses and fittings and why they matter

Type approvals for hydraulic hoses and fittings and why they matter

What is a Type Approval?

Type Approval is granted to a product that meets a minimum set of regulatory, technical and safety requirements.

Hydraulic Hose Type Approvals - Boat, Sea, Marine Approvals

Generally, type approval is required before a product is allowed to be sold into a particular country or industry sector, so the requirements for a given product will vary around the world.

The requirements can also differ from industry to industry.

For example, SAE J517 is a Society of Automotive Engineers standard that tells a manufacturer how to make a variety of hose products.

This does not necessarily mean that a hose will automatically be able to work in that industry. It may still require a TYPE APPROVAL.

Marine Approvals

Marine Surveyors

As maritime vessels will always work in an environment of risk, maritime insurers use marine inspectors as expert assessors to report on the condition of the vessels being insured.

Hydraulic Hose Type Approvals - Freighter, Cargo, Shipping Containers

A marine surveyor is a person who conducts inspections or surveys of marine vessels to assess, monitor and report on the vessel’s condition, and on the condition of any products that have been installed within them.

While marine surveyors are sometimes employed by the insurers directly, they will maintain a certain professional autonomy in order to provide an unbiased view.

Marine surveys typically include an assessment of the structure of the vessel, and of the machinery and equipment used aboard that vessel.

Hydraulic Hose Type Approvals - Marine Surveyor in Action

This can also include equipment intended for use on a new or existing vessel, in order to ensure compliance with various standards or specifications.

This will include a survey of navigation, rescue and safety equipment, as well as any industrial components used on the vessel, such as hydraulic components and hose assemblies.

Safety at sea

The overriding reason for marine surveys is safety.

For example, fire is a very dangerous condition for those aboard a vessel. This is due to a lack of breathable air in confined spaces, and the fact that there are limited avenues of escape from a vessel.

Hydraulic Hose Type Approvals - Flames, Fire at Sea

The intention of marine approvals is to minimise these risks.

When surveyors are examining hose assemblies for use on a vessel, they will be looking for a type approval for that product.

This means that the assembly will need to be formally approved as being a product safe for use aboard a maritime vessel. The assessment will include fire resistance as an important consideration.

The approval process is conducted by an approval body.

The Type Approvals Process

The process for gaining type approvals for hydraulic hose assemblies is simple.

When a product is made and sold as meeting or exceeding a standard, this is self appointed by the manufacturer.

For example, RYCO T28A hose exceeds standard SAE 100R2AT because it has been designed to do so, and we have proven its performance through extensive and continual testing.

Hydraulic Hose Type Approvals - The RYCO Process

A type approval is when a third party independently assesses the performance of the product, and issues a statement that the product meets all necessary performance requirements.

This statement is a type approval certificate.

Type Approval Certificates

When a type approval is awarded to a product, a certificate is issued by the surveyor.

The certificate will clearly state the products that are included.

Hydraulic Hose Type Approvals - Certificate Examples

If there are service restrictions placed upon the use of the product, then these will also be clearly defined in the wording of the certificate.

Approval certificates have a sunset clause, which means that the type approval for that product will need to be reassessed after a defined period of time, e.g. 5 years.

Pages 43-49 of the RYCO Product Technical Manual show the approvals for the RYCO products.

Hydraulic Hose Type Approvals - Product Technical Manuals

IMPORTANT: The approvals shown in the RYCO Product Technical Manual may not be the most current.

Please refer to the company website, www.ryco.com.au, or contact the RYCO Hydraulics quality department for the current status of all approvals.

Why Type Approvals Matter

In a thriving industry, it is important to set yourself apart from your competitors. Customers will often ask you to state your case, and tell them why your products should be considered above others.

The approvals for RYCO’s products are a tangible point of difference. The majority of RYCO products have been independently assessed and type approved by multiple parties – in all sizes.

This is a difference worth noting, compare the number of approved RYCO hydraulic hoses against those of a competitor.

Want more information?

Make sure you select the right hydraulic hose for your next project. Download our 15 Keys To Selecting The Right Hose guide today.

How to use the RYCO proof test rig – Machine Operation

In this second part of this series on impulse testing, we discuss how to use the proof test rig to safely test your hydraulic equipment set up.

Machine Operation

Connect the assembly

Prepare the connection.

Select an adaptor to suit your hose assembly and fit it to the rig.

RYCO Proof Test Rig - Connect the Hose

Ensure you’re not damaging any thread at this point.

Fit your hose assembly to the rig. Use two spanners to tighten the hex, so as to not damage any parts.

NOTE: When fitting an adaptor, it is vital that the connection is leak free. When the rig creates a high pressure, it does so with a minimal amount of fluid. A small leak will limit the amount of pressure that can be produced.

Purge the hose

Leave the other end of the hose uncapped.

RYCO Proof Test Rig - Vent Fluid Through Hose

Open up the High Pressure valve by turning anti-clockwise, and open up the pre-fill valve by turning it to the “‘on” position.

Allow the fluid to vent through the hose.

Cap the hose assembly

Elevating the hose will ensure that all of the air is purged from it.

RYCO Proof Test Rig - Elevate the Hose

Once all of the air has been evacuated through the hose, close the prefill valve, but leave the hose elevated.

Loosely fit a blanking plug or cap to the end of the hose.

Slightly open the prefill valve again to be sure that all air is exhausted.

Finally, tighten the plug or cap, and ensure it is positively sealed.

You may want to straighten the hose in preparation for the test.

Release the safety chain and close the door

Close the door, ensuring you’re standing well clear.

RYCO Proof Test Rig - Close the Door

Note: The door movement may be erratic and sudden movements may occur. If there are others in the vicinity, ensure that they are well clear also.

Close the High Pressure Valve

Close the High Pressure valve by turning it clockwise.

RYCO Proof Test Rig - Close HP Valve

NOTE: Take care not to over-crank the valve, or damage to the needle or sealing seat will occur.

Open the Air Valve

Next, open the Air Valve.

RYCO Proof Test Rig - Open Air Valve

IMPORTANT: Insure that the regulator is set to its minimum set pressure before opening this valve. (Ensure that it is fully wound back, and the gauge is as close as possible to zero).

Apply a low pressure to the hose

Slowly increase the pressure by winding the regulator clockwise.

RYCO Proof Test Rig - Apply Low Pressure

Pressure is displayed on the digital gauge.

Stop when the gauge displays around about 3Mpa, or 30 Bar. (Aproximately. 400 psi).

Check for leaks

Inspect the hose to ensure that there are no leaks.

RYCO Proof Test Rig - Check for Leaks

Apply the test pressure to the hose

Finally, wind the regulator clockwise until the required test pressure is reached.

Stabilize the test pressure

Once the test pressure is reached, back off the regulator to stop the pump.

RYCO Proof Test Rig - Stabilize test pressure

NOTE: Care must be exercised due to the time it takes to wind back the pressure on the regulator.

Check for leaks

Once the test pressure is set, back off the regulator fully to stop the pump.

RYCO Proof Test Rig - Look For Leaks

The pressure should stay constant. If the pressure drops, it is most likely due to leaks.

If there are leaks, locate them by observing the assembly through the windows.



Normal test duration is between 30s and 60s.

RYCO Proof Test Rig - Wait for test to complete

Some hoses (e.g. TEFLON hose) use a different proof test pressure or duration.

Have a clear understanding of the required testing process before you begin.

Relieve the pressure

When the test is complete, relieve the pressure by opening the High Pressure valve. (Turn counter-clockwise).

RYCO Proof Test Rig - Relieve the Pressure

IMPORTANT: Check the pressure gauges have returned to zero before opening the door.

Remove the assembly from the rig

Remove the cap or plug from the loose end of the hydraulic hose.

Remove the hose assembly.

RYCO Proof Test Rig - Remove Hose Assembly

Gently clear the test fluid from the hydraulic hose by using compressed air.

Clean the inside of the hose with a foam pellet

Complete any relevant paperwork. Prepare the assembly for shipping.

Important Safety Tips

Remember that fluid pressure is extremely dangerous.

If used as per instructions, the pressure will be inside, with the people outside.

RYCO Proof Test Rig - Safety Warning

Do not under any circumstances try to override the pressure safety dump switch on the door.

Do not “Burst Test” any parts or assemblies in this rig.

Want more information?

Read part 1 of our information on using RYCO’s proof test rigs to understand the important safety procedures and the controls that are available on the test rig machine.

Make sure you select the right hydraulic hose for your next project. Download our 15 Keys To Selecting The Right Hose guide today.

How to use the RYCO proof test rig – Safety & Controls

How to use the RYCO proof test rig – Safety & Controls

In this first part of this series on impulse testing, we discuss the importance of safety procedures and the controls that are available on the RYCO proof test rig.

Supporting Documents for the RYCO Proof Test Rig

Refer to these supporting document to ensure you fully understand the process and safety measures required. RH-SWP-9 Safe Work Procedure – Proof Test Rigs RH-Wl-13 Work Instruction – Internal Proof Pressure Test SAE J343 Test and Test Procedures for SAE IOOR Series Hydraulic Hose and Hose Assemblies AS 1180.5-1999 Methods of test for hose made from elastomeric materials – Hydrostatic pressure.

Safe Work Procedure

Before operating the machine, refer to the latest edition of RYCO Safe Work Procedure RH-SWP-9. (Step 1 – Preparation)

RYCO Proof Test Rig - Safety Procedures

Prior to switching on power, check the condition of the power cord to ensure that the plug is secure, that the cord is not damaged or frayed, and that a current electrical safety test tag attached.

Ensure the electrical plug is securely fitted in the socket. This applies to both the Air Compressor and the Test Rig in general.

If an extension lead, or power board is used, the above also applies. Ensure that the cord is correctly routed and clear of the floor, so as not to cause a tripping hazard, and to reduce the possibility of the cord being damaged by sharp edges or falling objects.

Ensure that the area where work is being carried out is well lit, and that there are no trip hazards, or other debris.

Ensure that the viewing windows are in good condition, are clean and can be seen through.

Before applying power to either the compressor or test rig, ensure that the air receiver of the compressor receiver is drained and that the drain cock closed. Ensure that there is adequate fluid in the reservoir of the test rig. Check the compressor oil level before starting.

Connect the air supply to the test rig.

  • Safety Glasses
  • Safety Boots
  • Protective Clothing
  • Waterproof Gloves and Apron are optional


This rig is designed for Non Destructive Testing Only!

RYCO Proof Test Rig - Safety Warning

Under no circumstances are assemblies to be burst tested.

Proof Test Rig Machine Controls


This unit uses ‘air over oil’ pumps to pressurise a fluid.

Proof testing is a process where a hose assembly is pressurised to prove that it can hold pressure. Therefore this can be regarded as a test to ensure that a manufactured assembly is ‘Fit for Purpose’ before it is fitted.

RYCO Proof Test Rig - Controls Overview

This is often a required test where the hose will be fitted in close proximity to personnel.

This test rig creates a static and regulated high pressure to safely test the hydraulic hose in an enclosed environment.

An emulsion of Water and Oil is used as the pressure medium.

Compressed air is made available to an ‘Air over Oil’ piston pump at a regulated pressure. The air pressure is intensified (amplified), and applied to the test fluid. The ratio of Air to Fluid pressure is 200:1.

RYCO Proof Test Rig - Overview of System Design

Therefore if 50 psi air pressure is applied, the static hydraulic pressure output is 200 times 50 psi, (10,000 psi).

Controls: Low Pressure

Air Valve

This valve isolates the air supply to the air over oil piston pump. This is a “Ball Valve”, and therefore turns on and off over a 1/4 turn.

RYCO Proof Test Rig - Air Valve

The valve is shown in the photo in the “On” position. To turn it off, turn the handle clockwise 1/4 turn. (The air supply is isolated when the handle is pointing downwards).

Air Gauge

This Gauge displays the pressure available to the air over oil pump. This pressure is controlled by the regulator.

RYCO Proof Test Rig - Air Gauge


This control varies the pressure available to the air over oil pump. Turn the knob clockwise to increase the pressure, and counter- clockwise to decrease the pressure.

RYCO Proof Test Rig - Regulator

The controlled pressure can be read on the Air Gauge.

The knob incorporates a lock. Pushing the knob downward will lock the knob, and not allow adjustments. Pulling the knob upwards, (as shown), will allow pressure changes to be made.

Controls: Lid Control

Lid control

This is the lever for the pneumatic valve that operates the lid.

RYCO Proof Test Rig - Lid Control

Be aware that the lid may operate at different speeds up and down.

Ensure you are well clear of the moving lid.

Controls: High Pressure

HP Valve

This is the knob for a needle valve that vents the High Pressure. (Test Pressure).

RYCO Proof Test Rig - High Pressure Valve

Turn the valve fully clockwide to close the valve and allow pressure to build up.

Turning the valve counter-clockwise will open the valve and vent the pressure to tank.

HP Gauge

This gauge is an analogue read out for the high pressure side.

RYCO Proof Test Rig - High Pressure Gauge

It incorporates an adjustable red pointer needle which is used as a “quick glance” indicator.

Digital Read Out

A digital read out for the high pressure side. This gauge displays Megapascals, (Mpa).

RYCO Proof Test Rig - Digital Read Out

Conversion to Mpa:

10 Bar = 1 Mpa.

To convert from Bar to Mpa, move the decimal point one position to the left. (e.g. 600 Bar = 60.0 Mpa).

145 psi = 1 Mpa.

To convert from Psi to Mpa, multiply by 0.0069 (e.g. 5000 Psi = 34.5 Mpa).

HP Outlet

The high pressure outlet port is 1/2″ BSPT.

RYCO Proof Test Rig - High Pressure Outlet

The flat plate has a threaded boss into which an adaptor is fitted. This adaptor is sealed by the use of a high pressure face to face seal. It does not seal on the thread.

This adaptor can be removed and placed in a vice to facilitate the fitment of a test adaptor.

Care must be taken when re-installing, as damage can occur to the sealing faces.

Want more information?

Read part 2 of our information on using RYCO’s proof test rigs, and discover how to safely operate the machine to perform a test..

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