Throughout the year we diagnose hundreds of pump and equipment problems over the phone and have found that in most cases it isn’t a pump problem, but rather a system problem. Sometimes the best tool you can use to help us determine your pumping issue is a camera.
By sending us a few well snapped pictures from your camera, of the pump and/or system, will give us a greater understanding on diagnosing your pumping issue. In addition to visuals, if we know the suction pressure, discharge pressure, and air inlet pressure, most problems can be solved quickly.
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When someone asks me about a Yamada 1/2” pump, most people think about the NDP-15 series pump. However, there is another option called the DP-15. This pump uses the NDP-15 polypropylene liquid side, but uses the DP-10 air section.
The DP-15 is only pump available with a polypropylene liquid end and has the same elastomer options as the NDP-15 series pumps. Be advised: there is a significant difference in the maximum flow rates. The DP-15 series has a maximum flow rate of 7.4 GPM, while the NDP-15 series has a 13.5 GPM maximum flow rate. While the NDP-15 series is good for higher flow rates, the DP-15 is ideal for low flow rates, extended dead head and dispensing applications. Both pumps share a common liquid end kit, but require different air motor kits. The DP-15 uses a K115-AM air motor kit and the NDP-15 uses a K15-AM motor kit. Lately we have seen several pump failures due to improperly installed shaft cushions (p/n 770582). We have noticed that the problem occurs when a shaft cushion is installed in a pump that does not require it.
For instance, the shaft cushion is used on all NDP-40 and NDP-50pumps with rubber diaphragms, including Santoprene® and Hytrel® elastomers. However, the shaft cushions are not to be used on NDP-40 and NDP-50 pumps with PTFE diaphragms or any NDP-80 series pump. The purpose of the shaft cushion is to prevent the center disk from impacting the air chamber wall when operating at the far right of the performance curve. This isn’t an issue with the NDP-40 and NDP-50 pumps outfitted with PTFE diaphragms because the pumps are destroked and will not travel far enough to impact the chamber. This can, however, happen with the NDP-80 series pumps. A shaft cushion cannot be used because it will interfere with the center disk as it makes contact with the pilot valve. Lastly, if you have a rebuilt NDP-80 pump and cannot get it to cycle, check to see if it was rebuilt (incorrectly) with shaft cushions. Below is a quick reference guide to follow when determining whether you can install shaft cushions in your pump. Often, we get a request for a Pulsation Dampener with ANSI Flanges, rather than the standard NPT port. Yamada only offers the ANSI Flange port option on the AD-25 and AD-40 series dampeners. We do not offer ANSI Flange ports on the AD-10 and AD-50VKynar® series dampeners. In addition, the ANSI Flange on the Aluminum AD-25 and AD-40 series dampeners is a threaded companion flange that is Loctited in place (see image). All other available flanges will be fabricated. Please consult Yamada for pricing.
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. Terms:
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. 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. The installation of a Yamada high pressure pump is the same as a standard Yamada Air-Operated Double Diaphragm pump. The bottom port is the liquid suction; the top port is the liquid discharge, etc. The main difference is the pumps ability to generate twice as much discharge pressure as air pressure, a 2 to 1 ratio. If using hose or light duty piping on the discharge of a high pressure pump, you must make sure that it will be able to stand up to the higher discharge pressure. High pressure pumps will generate more pulsation than a standard AODD pump. With this in mind it is recommended that a suction stabilizer and a pulsation dampener be used with any high pressure pump. The sizing of a pulsation dampener for a high pressure diaphragm pump is different from a standard AODD pump due to the fact that a high pressure pump is a simplex pump, rather than a duplex pump. The working volume of a pulsation dampener for a high pressure pump should be 5-10 times the working volume of the pump. When using a high pressure pump, you cannot use an automatic dampener. You will need to use a manually adjustable or chargeable dampener on the discharge side and chargeable only on the suction side of the pump. In place of a pulsation dampener, a stand pipe may be used. Consult Yamada for help in selecting the proper dampener. High pressure pumps are available in metal only. These pumps are available in the NDP-20 (3/4”) series size and larger. PTFE diaphragms are not available in the high pressure pumps and a shortened diaphragm life should be expected. For questions or technical assistance, please contact Yamada. With the introduction of the XDP Series pumps we needed to use a proximity sensor other than the P1 and P2 sensors used on the rest of the Yamada product line, which sense the position of the C-Spool to count the cycles of the pump. The P1X does not sense the air valve position. Rather, it senses the pressure shift that happens internally when the air valve in the pump shifts. Please contact Yamada technical services for further information
In August of 2008 the NDP-20 / NDP-25 series pumps came with a new style diaphragm which has an o-ring molded into the air side. This change was made for two reasons:
To prevent air leaks where the diaphragm contacts the air chamber. To prevent a diaphragm from pulling out of place if there is excessive air pressure. On the thermoplastic diaphragms (TPO, TPE, PTFE), there is no o-ring molded in the diaphragm. Instead a separate o-ring is used to fill the o’ring groove in the air chamber wall. The new style diaphragms cannot be used in the old style pumps, however the old style diaphragms can be used in the new style pump when used with the air chamber wall o-ring. The old style diaphragm will continue to be available for a few more years. I often receive phone calls from end users about diaphragm cycle life and the first few questions I ask are:
Operating a larger pump at half throttle would extend the diaphragm life, consume less air consumption and overall provide less wear and tear on the equipment. |
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