The following is a comparison between the most widely used return filter elements for 20 ton class excavators (dimensions: 150mm diameter, 450mm height)

• When examining the outside of both Yamashin Original Parts and imitation parts, it can be difficult to see any big difference. However…

• When we examine these same filters with the outer steel cover removed, it is easy to see that the placement of the horizontal support bands by imitation manufacturers is inconsistent and improper. Although this may seem to be a minor issue, in fact these horizontal bands play an important roll in the proper functionality of the filter

• The proper connection of the filter media is naturally of very great importance to the proper functionality of a filter!
• Yamashin utilizes a metal band to tightly and securely connect the ends of the filter media. However, imitation manufacturers will often use glue to connect the filter media and in some circumstances, imitation manufacturers simply staple the two ends of the filter media together!
• If this connection of the filter media is not done properly, this will cause the filter to leak!

• Using the appropriate binding agent in the proper manner is another vital area of a filter’s construction.
• As shown in the above photos, imitation manufacturers use incompatible binding agents which leads to improper setting of the filter media and creates open air pathways. The result is that hydraulic oil and contaminants leak and the part is unable to properly and effectively control contamination
  

• The above pictures represent what is referred to the verification of fabrication integrity as the “First Bubble-Point Test.” By applying pressurized air into a filter element submerged in water, we are able to determine fabrication integrity of a filter. In other words, this test allows us to confirm the oil flow through a filter.

• As illustrated by the above photos, the Yamashin filter shows a regular and steady stream of air bubbles flowing out of the entire length of the element. 

• However, imitation parts (shown in the picture on the right) shows large bubbles coming from a small location. This shows that the fabrication integrity of the imitation filter is unacceptable and will be unable to provide contamination control since the vast majority of the hydraulic fluid will simply pass through such openings.
   
  　

• According to Japanese Industrial Standard (JIS), filter elements are required to be able to withstand over 0.6 MPa of pressure. Yamashin filters are, of course, able to comply with this standard and withstand more than 0.6MPa of pressure. 
• However, imitation filters collapse when less that 0.6MPa of pressure is applied. When such a collapse occurs with an imitation filter installed in a construction machine, this not only re-introduces dust back into the hydraulic system, but also allows pieces of binding agent, filter media and other large contaminants to enter the hydraulic circuit, causing a potentially huge problem for the machine.
  

Yamashin Filter Manufacturing Corporation.
Hydarulic Filter Group.

Phone: 81-45-311-1091 Fax: 81-45-311-2097
　

Copyright(C)1998-2003 Yamashin Filter Manufacuturing Corporation. All rights Reserved.