What is a gland seal?
The primary function of a rod seal, often referred to as a gland seal, is to prevent pressurised fluid from leaking out of a system whilst a rod reciprocates through its travel past the seal. A rod seal is often the most critical seal in a system as it seals the internal fluid or gas to prevent it from escaping out into the surrounding environment. While leakage past a piston seal will affect its efficiency, the system’s contents remain contained in the system. However, with a hydraulic gland seal, failure will allow external leakage, and it should be paired with an appropriate wiper and gland housing design to ensure correct operation.
How a gland seal works
A rod seal is used to contain pressure within a system to prevent leakage out of the gland. This allows maximum mechanical effort to be applied to moving the piston along the bore of a cylinder. Gland seals can be used either hydraulically or pneumatically, with appropriate seal designs for each system and application. Hydraulic cylinder rod seals are made to prevent leakage across the moving ram rod surface diameter, and therefore contain the system fluid or gas.
Types of hydraulic rod seals
There are two types of gland seals: single-acting and double-acting gland seals. Single-acting gland seals can have pressure applied from one direction and double-acting rod seals can have pressure applied from either side to drive the ram that the piston is fixed to both in and out. Individual rod seal profile designs show specific behaviours and performance, which need to be in line with the application’s requirement. Gland seals can be made in various materials, which will also influence the choice of the seal profile. When determining the best rod seal design and material for a particular application, consideration needs to be given to:
- Pressure expected
- Whether a single or double-acting rod seal is required
- The friction losses acceptable
- Whether energisation is necessary
Gland seal design
The design of the gland is important, as this will dictate what types of seal profile and material can be used in the application. Many high-pressure systems require very stiff, robust hydraulic cylinder rod seals, along with the associated guide rings to control the action of the ram rod. In such cases, it is usual to split the gland into several parts so that the gland seals do not need to be compressed into the gland and snapped into place, but can simply be assembled in place and the gland head bolted on with securing fixings once fully built up.
Given that our Rod Seals can be CNC machined to bespoke sizes, we can add material to compensate for worn or re-manufactured rod seal or gland seal conditions, and help restore the original performance of used equipment as well as provide components for new build designs.
Order your rod seals from Martin’s Rubber’s rod and gland seal catalogue
For general guidance, view our standard hydraulic gland seal profiles, where you will find our selection of standard rod seals listed as:
Each of our standard gland seals conform to BS ISO 5597:2010 & BS 5751:1987 (R05). S109 conforms to BS6984:1998 & BS ISO 7425-1:2002 & BS ISO 7425-2:1989. S116, S216, S117 and S117R conform to BS ISO 5597:2010 & BS 5751:1978 (R05). S121, S125, S139 and S141 conform to BS ISO 5597:2010 & BS 5751:1978 (R05), S124, S129, S138 and S142 conform to BS 6984:1998 & BS ISO 7425-1:2002 & BS ISO 7425-2:1989.
These styles can be rapid manufactured in a variety of different materials depending on the application. We also stock standard products for immediate shipment and fast delivery.
Please contact us on 023 80226330, to discuss your specific requirements so that we may advise on the best solution for your application. Alternatively, simply email us and we will be able to advise you further.