Hose Tube Failure

Hydraulic Fluids

Hydraulic fluids can be categorized as petroleum-based, water glycol or synthetic based (i.e., phosphate ester).  All types provide specific properties that need to be considered to meet the needs of a given hydraulic application.

In the past, hydraulic fluids were petroleum based fluids that could potentially cause problems by leaking into the ground and contaminating the area and water supply. Today, the industry is moving toward more environmentally friendly fluids where advances have led to many new generations of “green” fluids.

Green fluids are typically synthetic- or vegetable-based. Green fluid’s base compound may be biodegradable and non-toxic, however,  additives in the fluid may not be.

 

Synthetic fluids are primarily ester-based.

 

Vegetable oils are gaining popularity since they cost less than synthetic and are more biodegradable. They also have excellent lubricity and a high viscosity index. However, they have a limited temperature range with rapid oxidation at elevated temperatures.

Fluid Power Troubleshooting - Crimp

Poly Chain GT2 Sprocket Specifications

Poly Chain GT2 sprockets are manufactured to close tolerances to ensure proper drive alignment, tooth engagement, and overall drive performance.  Modifications such as reboring may result in unsatisfactory results in the belt drive system.  Strict adherence to the standard tolerances outlined below is highly recommended.

For any additional questions feel free to look through our other blog topics or contact us at ptpasupport@gates.com or 303-744-5800.

Calculating Sprocket Pitch Diameter

When working with synchronous sprockets you'll need to know about pitch diameter.

In the image below you can see that the pitch diameter on a sprocket is an invisible dimension that represents where the pitch line of the belt would be if it was wrapped around the sprocket. Calculating pitch diameter is simple. 

Pitch Diameter = (Belt/Sprocket Pitch) * (# of sprocket grooves) / π

More - Maximizing Hose Assembly Service Life

Maximum service life can be attained by following with the

recommendations shown below.

Hose Routing–Restraints, protect or guide hose (clamps) can be used to minimize risk of damage due to excessive flexing, whipping or contacting other moving parts or corrosives. Determine hose lengths and configurations that will result in proper routing and protection from abrasion, snagging or kinking and provide leak resistant connections.

Hose Length–Correct hose length determinations include considerations for length changes under pressure, machine vibration and motion, and hose assembly routing.

Hose Applications–Select the proper hose for the application.

Vacuum service (for example, Gates Global MegaVac®), special fluids or high temperature capabilities are among the applications requiring particular consideration and a specific hose. Do not use Gates hydraulic hose in place of permanent piping. When additional information is required, contact Product Application Engineering.

Maximizing Hose Assembly Service Life

Maximum hose assembly service life can be attained by following the recommendations shown below. 

Fluid Compatibility–The complete hydraulic assembly (tube, cover, reinforcement and couplings) must be fluid compatible. Phosphate ester and petroleum-based hydraulic fluids have drastically different chemical characteristics therefore it is important that the correct hose must be used. Hoses are compatible with many, but not all fluids. Gates G2XH and C5D hoses are unique because they are capable of handling both phosphate ester and petroleum-based hydraulic fluids.

Minimum Bend Radius–Do not bend or flex hose to a Bend Radius smaller than the recommended minimum Bend Radius or subject the hose to tension or torque. These can place excessive stress on the reinforcement and severely reduce the ability of the hose to withstand pressure.

Hose Size–The hose size (inside diameter) must be adequate to keep pressure loss to a minimum or required flow volume. Inside diameter that is too small for a given volume of flow results in excessive fluid turbulence, pressure drop, heat generation and tube damage. It is generally a best practice not to exceed16 feet per second fluid velocity in a hydraulic system. Using a larger I.D. hose will lower fluid velocity.

Maximizing Hydraulic Hose Assembly Life

Maximum service life can be attained by complying with the

following recommendations:

Working Pressure–The hydraulic system pressure should not exceed the rated working pressure of the hose. Pressure surges or peaks exceeding the rated working pressure are destructive and must be taken into account when selecting a hose. It is not safe to use hose assemblies above their rated working pressure.

Minimum Burst Pressure–Burst pressures are reference pressures intended for destructive testing purposes and design safety factors only.  Do not subject hose to the Minimum Burst Pressure.

Temperature Range– The hose should not be exposed to internal or external temperatures that exceed the recommended limits.

Consult Product Application when hydraulic fluids contain emulsions or solutions. Some fluids reduce the safe operating temperature of a hose therefore the fluid manufacturer’s recommended maximum operating temperature for any given fluid must not be exceeded, (i.e. water in a hydraulic hose).

Hose Assembly Performance

Hydraulic hose and hose assemblies have a performance life which is dependent on service conditions of the application

·       Subjecting hose (and hose assemblies) to conditions more severe than the recommended product limits can reduce service life

·   Subjecting hose to combinations of circumstances at or near recommended rating limits (i.e., continuous use at maximum rated working pressure while at maximum recommended operating temperature or minimum bend radius)

Injury to personnel and/or damage to equipment could be the result by not following proper selection, installation and maintenance procedures.

Hose assemblies in service should be regularly inspected for leaks, abrasion, kinks, cover blisters or other such damage. Assemblies showing signs of wear or damage should be replaced immediately.