Morisei Shoji Co.,ltd. faq & glossary

●As for glossary this

Q1. What is O-ring?
Q2. How to choose O-ring?
Q3. How long is the useful life of O-ring?
Q4. How to store O-ring?
Q5. What is the important point when installing O-ring?
Q6. When O-ring breaks after short period use.
Q7. Is it possible to export O-ring?
Q8. Does O-ring contains non environmental friendly material?
Q9. What is back-up ring?

Q1. What is an O-ring?
A. An O-ring is a circular ring which has a round shape section. Mainly rubber is used for the material. There are also O-rings made from resin or metal. O-rings are used for sealing up the vapor or liquid.

Q2. How to choose an O-ring?
A. There are two elements in order to choose an O-ring. They are the material and the size.

Material:
There are many factors to choose material from. Firstly, as for the environmental factors there are temperature, fluid, pressure, etc. Based on these factors materials need to be selected.
As for the temperature it can be referred to the temperature indicated in our catalogue as a benchmark. However if there is any other factor please choose the temperature range with allowances.
As for the fluid, typical fluid types are indicated in our catalogue. However if you can not find a particular fluid, please contact us. Using mixed or high density liquid, the condition will be harsher. Therefore if you are not certain which fluid type to refer, please contact us.
Pressure is related to hardness and tensility. Generally, in order to use under high pressure choose the one with high hardness. However, if the hardness exceeds the limit it causes breakage of the O-ring. As a benchmark, if the pressure exceeds 5 MPs more consideration on the selection of the O-ring is necessary. In case the pressure exceeds 10 MPs please contact us.

Size:
Morisei has more than a thousand standard products types including JIS. JIS products are designed using mm for the measuring unit. AS products are designed using inch for the measuring unit. If you are looking for a size outside the standards please contact us as we own a couple of hundreds of original molds.

Q3. How long is the useful life of O-ring?
A. It depends on the use environment. Using under the condition close to maximum temperature limit it might be less than one month. The useful life can not be measured in a simple way. The best way is using it as a trial for a certain period of time and check the status of the O-ring afterwards. Basically O-rings are consumable products. It is not recommended to use an O-ring more than three years continuously even used in a best environment condition.

Q4. How to store O-rings?
A. It totally depends on storage condition. Where is dark, cool and low humid place it may not change the appearance approximately for ten years even if the weather resistance of the O-ring material is low. On the contrary there are some materials that are degraded within a week if the O-ring is exposed to the direct rays of the sun and kept in a high temperature and high humidity place. Especially for O-rings made from low weather resistant materials, we recommend to use them quickly.

Q5. What is the important point when installing an O-ring?
A. It is to avoid damaging the O-ring. O-rings receive external stress such as hydro pressure and pressure from tightening. Damages often cause severance of the O-ring in those circumstances. In addition it is not appropriate to install O-rings stretching too much as this gives extra stress.

Q6. When O-ring breaks after short period use.
A. There are mainly two reasons for the breakage in a short time period. One reason is the choice of the design of groove, material or the size was not appropriate for the using condition. The other reason is there was some defect when it was installed or before the installation. However, statistically, the former is the main reason for the breakage most of the time. If this situation happens please contact us with as much detailed information of using condition. It is also necessary to keep the damaged O-ring and check it as it may have the trail useful to know the cause of the breakage.

Q7. Is it possible to export O-ring?
A. It is possible to issue documents based on the Export Trade Control Ordinance. Please inform us the fact that you are requiring the documents, the destination country and the purpose of product use (machine type) when you place an order.

Q8. Does O-ring contain non environmental friendly material?
A As for the material of the O-ring we are currently selling we do not intentionally use material listed on Eu RoHs (EU Restrictions of Hazardous Substances) and Green Procurement Standards during our manufacturing process.

Q9. What is a back-up ring?
A. In order to support the O-ring it is widely used especially in high pressure condition. It is not commonly used in low pressurized fixed parts. For dynamic parts it has a good effect even in low pressure condition. Please look into our O-ring catalogue for the details.

Thickness
The diameter of O-ring

Alias of Material
(1) Type 1 A, Type 1 B = NBR, Nytril, Bunazosin, Oil resistant rubber, Carbon-Hydrogen, etc
(2) Type 4 C, VMQ-50 = MQ, Q, Silicone, etc
(3) Type 4 D = FKM, FPM, Fluoride Rubber

Alias of Standards
(1) AN6227 = W1516, WP
(2) AN6230 = W1517, WG
(3) AS568A = AS568B and ARP

Compression set
This is a factor which has a great impact on the useful life of the O-ring. The lower the figure the longer the useful life of the materials is.

Flaw mark
When the O-ring is formed rubber flows into the mold and the flow creates a trail. The trail can be a similar condition to a flaw. If the flaw mark is large it causes problems when the O-ring is used.

Bite
When the O-ring does not fit properly to the groove, a part of the O-ring could be caught in the gap of main parts. This creates cracks to the O-ring and is called a ﾒBiteﾓ. This is a common case which causes breakage to an O-ring.

Swelling
When the choice of the O-ring material to the sealing fluid is not correct, the O-ring may absorb the fluid, and it makes the O-ring swelling. If this happens, the size of the O-ring changes, and the strength of the O-ring decreases dramatically. This causes breakage, hence leaking.

Page Top