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About flexpvc

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  1. I made some corrections and update to the above and posted it on our site: http://flexpvc.com/TechArticles/NominalBallValves.shtml Give it a look.:-)
  2. flexpvc

    Flexible tubing

    Yea, that's about the only way to settle this. :-) In the end, probably "much ado about nothing."
  3. flexpvc

    FlexPVC Images

  4. Semi OT, but the throttle body spacers don't really increase the hp/tq, but what they do is move the peaks because you are changing the vol. of air in the intake system as well as the length from the TB to the valve. What I've seen is that they tend to "rock" the curves about the peak point based on the length and the peak rpm point is based on the total vol in conjunction with the cam/ports combination, so it can move it up or down the rpm range. Back on semi-topic there is a gizmo the hucksters sell called a vortex generator [not to be confused with aerodynamic vortex generators which aircraft and race cars use with good results] which actually has vanes in it to "swirl" the incoming air. They claim more mileage and power.. but when they are tested, just the opposite is shown, less power, worse fuel mileage. So "straightening" the air is probably the best approach, just like in the example given above. Ie, it works! :-) Thanks for the reply.
  5. flexpvc

    Flexible tubing

    Overall, I agree. This is probably NOT a big deal. However, I don't know that I 100% agree with you on the "plasticizers go straight to air" statement. Pthalates belong to a class of chemicals called Semivolatile Organic Compounds, which as a general rule, are only marginally likely (semi, lol) to be apt to directly sublimate from a solid, through the aqueous/dissolved phase and out into the atmosphere. I see pthalates in groundwater regularly. Even though I technically disagree with the statement that they jump right out into the air, I agree that the likelihood of issues are small, and that most people run GAC which would remove it from the water column anyway. Hello Sir, Thanks for the reply. When I was saying they go to the air, what I mean by that is you have a hose. On the inside is a liquid under pressure above 1 ATM (water). On the outside of the hose you have air at 1 atmosphere. I realize it's a tiny difference, but it is a difference non-the-less. Also the ID of the hose is much smaller than the OD of the hose, therefore the surface area on the OD is greater than the surface area of the inside of the hose in contact with the liquid. So it's my contention that these two factors would cause the pthalates to "migrate" toward the OD of the hose, not the ID. I have no doubt you have found them in ground and every other kind of water. No disagreement there. :-)
  6. flexpvc

    Flexible tubing

    And years ago you could have done that. But the last several years we've seen a flood of imported products. As one of the original sites (if not the first site) selling flexible pvc pipe online, we get tons of offers to sell to us... all from imported distributors. So we know what is out there. :-) What has prompted me to write this is the no. of customers who have come to us with defective product (bought from other sites) over the last 2 years. 2011 was the big year for the imported stuff and it seems to break down in about 2-3 years. So I expect much more in the coming years. ;-/ Please don't blame me, I'm just the messenger. ;-)
  7. flexpvc

    Flexible tubing

    Is there any major chemical difference (rigidity aside) between the clear flexible vinyl tubing and the flexible PVC that you guys offer? Article is sort of vague on whether they are referring to the stuff you guys offer or the other tubing or both. I have always used the flexible vinyl for my pump returns and have used the flexible PVC several times on other projects. Throwing out any obvious cognitive dissonance, I like to see something other than anecdote when an affirmative claim is made for or against a product, which that article is clearly doing. Question 1, Almost any tubing or hose other than Silicone or Rubber will have some plasticizer in it. Both the clear vinyl tubing (which is really PVC, you can even glue it with standard PVC Glue/Cement/Primer) and our flexible pvc pipe have the same plasticizer in it. I believe they used the term "vinyl" not to confuse people when the products first started to be sold and the name has stuck. But they are mostly the same materials, just manufactured in a different way. Question 2. I gave the names of the plasticizers. The one we use and the one banned and shown to be maybe harmful. It'll take a minute on google to look them up. I know for a fact some, maybe much, of the flexible pvc pipe sold online NOT from our site is imported. If you want to check yourself, just ask them for a certificate of origin. If you exporting the product by NAFTA they have to provide a COA. It's a legal document. It must show where the product is made. As for the plasticizer you'd have to ask. They may or may not be truthful. Did I misunderstand your 2nd Question? If so please let me know and I'll try again. :-) Thank you.
  8. Hello, This is Eric from FlexPVC.com We've learned 99.9% of all aquarium people are very specific on their tanks. They go to a lot of expense and effort to get them just perfect. But there is a common mistake amost everyone has in their system: Nominal Ball Valves. Aka, MIP (Molded In Place) ball valves. Why is it a mistake? What does Nominal mean? Nominal means "in name only." For example a 1/2" pipe is not 1/2". Just like at the lumber store a "4x2" is not a 4" x 2". Those are nominal names. A 1/2" Sch 40 pipe is almost 5/8" ID (inside diameter) and almost 7/8th OD (outside diameter.) So why do they call it 1/2"? Just tradition. It's about 1/2", but the tolerance is the OD not the ID. Confusing, I know. Just like a 4x2 (lumber) is 3.5" x 1.75". So what does this have to do with Nominal Ball Valves? Well they are worse. A 1/2" Nominal Ball valves is WAY LESS than 1/2" ID. It's about 7/16". A 2" Nominal Ball valve is about 1.5" ID. If you don't believe me, go look at some. I made a video showing this and put in on youtube along with a solution: (basically if you want a full flow ball valve, you buy the next larger size and use reducer bushings to take it back down to the size of the pipe you want to us.) I hope you found this informative. :-) And now you may know why your 1000gph pump really isn't putting out 1000gph... (well actually that's a whole 'nother post.... ) HTH Eric Flexpvc.com All Rights Reserved
  9. Hello, This is Eric at FlexPVC.com® again. This time I'm going to write about pump ratings. Most of the time people buy a pump based on it's flow. GPH (gallons per hour) or GPM (Gallons per minute) or LPM, etc for the metrically inclined. But what most people don't know is the conditions these pumps are rated at. I'm going to explain how they rate them and how you can get closest to the full rating. #1. Most all pumps are rated with a flooded suction and with at least 10 times the diameter of straight pipe going into the suction side of the pipe. That means a pump with a 1.5" entrance will have at least 15" of straight pipe going into it. The pumps are engineered to pull from that STRAIGHT column of water. So if you have a 90 or any other direction change on the input of your pump, you will never see the full flow rating. #2. Most pumps are rated with a draw from a tank, a very large tank. This provides almost a perfect smooth source of water to draw from. Not a tank with a bunch of pumps swirling the water around. Back in the day, Jacuzzi pumps were tested with a 8' in diameter, 30" deep cistern. Now, how do you get around these problem? #1, Obviously try to keep your intake straight and pull from a pool of water that does not have any swirls in it. #2. For large pumps (1/2hp and larger) you can build a flow straightener. Here is one I built for a 5hp 25K gph pump. Here is what it looks like on the inside before the straighteners are inserted: (notice the nice radiused intake. Very important!) Here is what it looks like after they are inserted: I used SDR21 purple pipe because it's the cheapest pipe you can buy and it's pretty thin wall. You just "stuff" the pipes in till they are tight. They will bend and flex around. That's what you want. After they are all tight, you just dribble primer in all around them. Each contact point of each pipe will weld together. You then add glue to bond them in case of vibration. Then you put the other end on and you have a flow straightener. Just this one mod alone increased flow from 21K gph to 23K gph. Initially the people who did the plumbing had the Tee right up against the pump. Moving it 20" away we went from 18K gph to 21k gph. The pump is still a little away from it's 25K gph rating, but that is because it's not in a true flooded suction situation. The water reservoir is about 30" deep and the pump is about 12" deep so it has to draw up about 18". That is why it does not get to it's rated 25K gph. But when I got there the pump was only at 72% of it's rating and when I left it was at 92% of it's rating and the flow over the waterfall was greatly improved. Anyway, I hope you found this informative. Eric FlexPVC.com® All copyrights reserved.
  10. flexpvc

    Flexible tubing

    I'm humbled. Thank you sincerely. :-)
  11. flexpvc

    Flexible tubing

    Also, and this is very important, for anyone that bought Non-USA flexible pvc pipe in the past and wants to replace it, we are offering free shipping on replacement rolls. You have to provide your hard copy of your receipt from the location you bought it from that sold you non-us made flexible pvc pipe, and we'll help you get that stuff out of your system. Thanks
  12. flexpvc

    Flexible tubing

    Hello, This is Eric at Flexpvc.com. Seems this subject comes up every few years. So to help quell the confusion here is the data. All of our PVC products (sold at Flexpvc.com) contain a plasticizer called Di-isononyl Phthalate (or DINP). Several years ago, there was a great deal of scrutiny on a plasticizer called Di-octyl Phthalate (or DOP). DOP was one of the most commonly-used plasticizers for decades, but was linked in some studies to various health risks...If I remember correctly, some lab rats exposed to high levels of DOP as juveniles exhibited stunted organ growth, obesity and heart problems as adults. This led to a lot of bad publicity that resulted in DOP (Sometimes also called DEHP) being banned in many parts of Europe and the USA. It also made the word "Phthalate" a popular "danger word" amongst many consumer groups. IMPORTANT NOTE: There are many places on the net selling flexible pvc pipe (referring to it illegally as "flex pvc" our registered trademark) made in MEXICO, China and other none US, non-UK locations. Since DOP has not been banned from those locations and since it's cheaper to use then the other plasticizers, you can bet it's probably being used. That is why we have the page "Why is it important to buy Made In The USA Flexible PVC Pipe from Flexpvc.com" (see http://flexpvc.com/MadeInTheUSAFlexPVCPipe.shtml) Many people don't realize that "phthalate" actually refers to a whole family of chemical compounds. There are many that are demanding that ALL phthalates be banned. For what it's worth, our plasticizer (DINP) is considered one of the most benign, and is commonly used in food-handling and baby products. As for "off gassing" or "leaching" that too became a popular concern in the media a few years back and is basically just a fancy term for "evaporation." As you know, the plasticizers will eventually evaporate of the PVC leaving it stiff and brittle. Many people don't seem to realize that this is why you get that cloudy film on the inside of your car's windshield.....that is from the plasticizers evaporating from the vinyl dashboards, trim and seals in your car. But where does it "evaporate" to? Not the water. That's a higher pressure zone. Evaporation always goes in the direction from higher pressure to lower presure. So they come out into the air. I suppose if the plasticizer we used was the dangerous one and if you stuck your head under the tank and breathed it for months on end.... it might have a health risk. But we don't use COP or DEHP and you don't live under your tank, and the fish don't "breath" is because it goes from the hose/pipe to the atmosphere not the water. :-) In short, unless someone is eating PVC by the pound, the actual exposure to anything "dangerous" from our PVC products would be about the same as an average person experiences handling plastic products through the course of the day (holding a phone, typing on a keyboard, eating with plastic utensils, drinking through a plastic straw, etc.) As always all we can do is offer the best information available and let the customer decide. :-) As for the article on silicone tubing.... silcone is a fine product. But I do question the hit piece on pvc without the data. ;-)
  13. Okay, here is an annotated view.
  14. as soon as the power turns on, your pumps willl start filling the top tank and as soon as the water level reaches the intake (the horizontal screen) the water level will be higher and start to flow. :-)