Nitrogen Gas Springs: Frequently Asked Questions

What life can we expect from nitrogen cylinders?
How do we know how many cylinders we require?
Can we link independent units back to an external charge point on the outside of the tool?
What is the force increase over the stroke of the gas spring?
What is the maximum speed we can stroke the springs at?
How are NITRO-SPRINGS tested for durability?
What guarantees do NITRO-SPRINGS come with?
Do Nitro-Springs conform to the latest PED requirements?
Do you have another question not answered here?

What life can we expect from nitrogen cylinders?

The life expectancy of nitrogen die cylinders is determined by many factors. In ideal conditions we would expect to achieve 100,000 stroke metres, this being the length of piston to travel through the seal unit before failure. (It must be remembered that at 50mm stroke, one cycle will be equal to 100mm of movement).

Like all mechanical devices, if they are looked after they will last longer.

How do we know how many cylinders we require?

Experience pays dividends in this field. Tonnages are the "Black Art" of press tool design and many force requirements are based on previous job knowledge. If you are looking to take a tool off of a cushion the pressure required can be worked out by using the following formula:

Cushion area in inches squared x running pressure in PSI = Total pad pressure in pounds. Divide the result of the above by 2.2 and this will give you the total pad force in KG. Divide this by the number of rods you require and this will tell you the size of cylinders needed.

Can we link independent units back to an external charge point on the outside of the tool?

Using our unique "NITRO-FLEX" Hose system you can link all standard NG range springs. Available in standard sizes, off the shelf, or made to order in specific lengths. On new tool build we are able to mount and link the system here in our works. This takes a lot of time consuming work away from the toolmaker, and ensures a leak-proof system.

What is the force increase over the stroke of the gas spring?

Standard gas springs have a sixty five percent increase in force over their stroke. This is caused by a reduction in free volume for the nitrogen as the piston enters the cylinder during the stroke.

The LF series springs are designed to reduce the force increase to just over twenty five percent. This is achieved by using larger bodies thus lessening the reduction in volume as the piston enters the cylinder.

In a linked system it is possible to use an external pressure vessel to further increase the initial gas capacity once again lowering the reduction in volume as the pistons enter the cylinders.

What is the maximum speed we can stroke the springs at?

The recommended maximum stroking speed for NITRO-SPRINGS is 35 metres/minute; it must be remembered that this is not the cyclic speed of the press. We recommend a maximum stroke rate of sixty cycles per minute.

How are NITRO-SPRINGS tested for durability?

Arduous dynamic testing is carried out on all of our products. All aspects of the gas spring manufacturing process are monitored by the latest SPC systems ensuring the very highest production standards, as demanded world-wide by all of our customers.

What guarantees do NITRO-SPRINGS come with?

All NITRO-SPRINGS come with a full 2-year guarantee. We are aware that most new tooling, using gas springs, will not enter production for at least 12 months. When most of our competitors warranties are expiring NITRO-SPRINGS are just entering their second year of cover. Once again this illustrates our supreme confidence in our product.

Do Nitro-Springs conform to the latest PED requirements?

Metrol Springs is proud to confirm that all of its products meet the latest Pressure Equipment Directive.

Do you have another question not answered here?

We will be delighted to help you with your query. Please email your question to technical@metrol.com. You may prefer to use our feedback form but either method of contacting us will guarantee a fast response and we look forward to helping you.