Dave’s Corner: Metal Finishing

In addition to our standard product line, Yamada offers a variety of surface finishes for our stainless steel pumps. These finishes are primarily used for food, pharmaceutical and high purity applications. Our FDA Series of pumps come with an electro-polished finish (reference figure A).

The process involves immersing the part in an acid bath, then an electric current is introduced to help pull out the in the stainless steel, removing surface contamination and leaving the part with a shiny finish.

Additionally, Yamada can also mechanically polish any stainless steel pump that is 1” of size or smaller. This process helps to remove the porosity from the stainless steel. Parts can be polished to either a 20 RA finish (180# grit) or a 10 RA finish (320# grit). The 20 RA finish is typically used in the food and pharmaceutical
industries; whereas the 10 RA finish is primarily used for semiconductor applications. Yamada pumps that are considered electro-polished are first mechanically polished.

electro-polished

Terms:

  • Electro-polished – acid dip with electrical
  • Passivated – acid dip, no current applied
  • Mechanically polished – uses mechanical action to remove porosity from surface
  • 20 RA finish (180# grit) – food and pharmaceutical
  • 10 RA finish (320# grit) – semiconductor

Dave’s Corner: AD Dampener Control

Yamada makes an automatic pulsation dampener, known as the AD Series Dampener. The AD Series Dampener is self adjusting and runs off the same regulated air supply that powers the pump.

In most situations, the dampener does not need an air regulator of its own. However, there may be times when a separate air regulator for the pulsation dampener is helpful.

An example of this would be using an NDP-40BAN with an AD-40AN pulsation dampener. When running at 90 GPM at 50’ TDH (22 PSI) the air requirements are 100 PSI air pressure and 100 SCFM air volume.

dampener diagram

Running at that point on the performance curve generates a difference between the air pressure and the discharge pressure of 78 PSI. With the differential pressure being that high the dampener will consume more than the normal amount of air.

The solution to the pulsation dampeners high air consumption is to install an air regulator in the dampener air line (see Fig. 0.1). We recommend setting the dampener air pressure 10% above the discharge pressure. So with a discharge pressure of 22 PSI, adjust the dampener air pressure to 24 PSI.

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