Hydraulic cylinders are commonly found in industrial machines. Consisting of an actuator, it uses hydrostatic energy to generate force. Hydraulic cylinders essentially use fluid to create a pull or push force. Because they contain fluid, however, they require the use of seals. There are hydraulic seals found in most hydraulic cylinders. What are hydraulic seals exactly?
Overview of Hydraulic Seals
Hydraulic seals are gasket-like rings that are designed to seal areas between the components in a hydraulic cylinder. Hydraulic cylinders contain many different components, some of which are exposed to the fluid. To prevent fluid from leaking around these components, hydraulic seals are used. Hydraulic seals are designed to fit the components in a hydraulic cylinder while creating a leak-proof seal around them.
Hydraulic seals are essentially o-rings. However, they feature a groove within the lip that allows them to fit the components with which they are used. The groove will slide over the component to create a leak-proof seal. Even when the hydraulic cylinder’s piston moves and its fluid pressurizes, the component won’t leak. The hydraulic seal will keep the fluid within the appropriate container so that it doesn’t leak around the component.
Hydraulic Seal Materials
You can find hydraulic seals available in several materials. Rubber is a common material used for hydraulic seals. Rubber hydraulic seals are elastic, resistant to cracking, and long-lasting. There are also polyurethane hydraulic seals. Polyurethane hydraulic seals feature many of the same qualities as those made of rubber, but they are typically stronger and better protected against wear. While not as common as rubber or polyurethane, some hydraulic seals are made of polytetrafluoroethylene (PTFE). PTFE is a synthetic material that’s flexible, strong and resistant to extreme temperatures.
Composite Centrifugal Pump Wear Rings
Pump Composite Wear Ring Key Features
Pump wear rings are simple components, but they have a profound impact on pump reliability, efficiency, and safety.
Most centrifugal pump designs include replaceable rotating wear rings on the impeller (impeller wear rings) and stationary wear rings inside the casing (case wear rings). The wear rings in a pump serve three key purposes:
Create the contact area between rotating and stationary parts inside the pump
Reduce internal recirculation from pump discharge to pump suction or between stages
Create hydraulic forces which stabilize the pump rotor
The wear ring running clearance impacts pump discharge pressure, flow, efficiency, power consumption, vibration, and cavitation. Using composite wear rings with reduced clearance has a positive impact on all these factors.
Composite Centrifugal Pump Wear Ring Advantages
Long-term, large-scale field studies have shown that composite materials can improve pump life by up to 100%, reduce vibrations, and reduce seal leaks. Field tests and pump test stands have shown that reduce clearance can improve pump efficiency anywhere from 2-5% for typical process pumps. Additional pump composite wear ring material benefits include:
Eliminating the metal-to-metal contact points essentially eliminates the risk of galling or seizure
The wear rings will not seize or gall during slow roll or alignment
The pump will have a better tolerance of run-dry events and other process upsets, with a chance of surviving extended off-design conditions
Lower vibration due to improved damping at the wear rings
Fewer seal leaks due to reduced pump vibration and reduced shaft deflection due to tighter wear ring clearance
Higher efficiency due to lower leakage losses across the wear rings
Guide Rings | Wear Rings
The guide ring or wear ring guides a hydraulic cylinder piston and rod and absorbs lateral forces. Metal to metal contact between the moving parts of the cylinder, for instance between the piston and the cylinder or the rod and the cylinder head. The advantages of these non-metallic guide rings (compared with traditional metal guide rings) are, among others, a high bearing load capacity, the elimination of local stress concentrations, wear resistance, a low coefficient of friction, and low maintenance costs.
Advantages Guide Ring
The tapes can be supplied either cut to length or by the meter, to be cut according to requirement.
High load capacity (compressive strength), low wear, and reduced friction due to an additive of carbon to the PTFE material.
No tendency to stick-slip in the case of low sliding speed.
Available in practical dimensions.
Simple groove designs.
Simple piston designs without metallic contact of the sliding surfaces.
Profile geometry is exactly suited to work in lubricated air as well as dry and oil-free air.
