Post by gjhinesjr on Feb 22, 2016 21:32:35 GMT -5
The recent vacuum pump thread spurred me into wanting to help clear up some information about vacuum pumps.
I'm certainly not a professional dairyman or serviceman, but I am the supervisor for a municipal water plant and take care of countless pumps and motors of all kinds. Including vacuum pumps. Likewise I'm a bit of a gear junkie.
So I thought I would make a post that might help some understand this whole vacuum pump deal. I cringe when I see people seeking out ancient surge vacuum pumps just to power their system. When they could easily get a brand new pump that would work just as well if not better.
Without further ado.
In short, the vacuum pump is what powers your whole milking system. It's responsible for sucking the milk from the cow, and in bucket milker cases, moving the pulsator as well.
There are basically two parts to your “pump” if you will. The actual pump, and the motor that powers it. There like a team. Can't have one without the other.
The pump:
The pump is what actually moves the air. And in a vacuum system we're trying to remove the air from the system. A compressor simply does the opposite. There's technically no difference between the two. However there are some unique qualities that we're looking for in a milking setup.
In a milking system, it's a relatively low vacuum situation. Vacuum is measured in “inches of mg (mercury)”. A perfect vacuum being considered roughly 29”. A typical milking system is set to around 11-13 inches. For lowline parlors, I've seen less, for high line milking parlors, sometimes more like 15 inches. What we're most concerned with in a milking system is the volume of air being moved, which is measured in cubic feet per minute (CFM). The reason being is that you need a lot of air leaving the system for everything to work. Your claw has 4 openings, that all need to be removing air to stay on, the milk takes vacuum to suck out, and transport through your system. If your cow kicks your claw and a shell falls off, it's nice when the whole claw doesn't fall off. This takes volume. The reason I mentioned the air compressor was because a lot of people think about going this route. And in most cases, with a bucket milker, it will work. The problem is that an air compressor (at least in smaller home units) is designed to move a relatively small amount of air, but at a very high pressure. So when you go to run your milking system off of it (by hooking your hoses up the opposite way as you would using it as an air compressor), it wont be moving very much air. And the additional ability of the compressor to suck a high vacuum, isn't needed. So it's a limiting piece of equipment in that regard. I would venture to say that most vacuum pumps you see for industrial applications are going to fall into this category. The cfm simply isn't there. But again, you have to know your needs in order to say.
In my opinion, based off my research for pipeline systems. Most bucket systems could stand some extra CFM. I've seen a lot of people talking about needing four hands to simultaneously put on the milking claw otherwise it wont stay on. This is because you don't have enough CFM. Watch some videos of professional parlors putting on milking units and you'll hear that “shhhhhhh” sound the whole time the unit goes on. From what I've read, no matter how few cows are on a pipeline vacuum system, they recommend 30 CFM, and an additional 5-10 CFM for each additional milking unit after about 3. The literature varies. Again, I'm a bit of a gear junkie, and want professional performance no matter what I'm doing. So I use that as my basis for decision making. Obviously with bucket systems, we don't need to slug the water through the pipeline during cleaning, which is a major need for such high CFM. But going back to pumps. Most pre-built bucket systems I've come across use a Conde brand pump. If you compare their single bucket system pump setup, it makes about 5 CFM. Quite a difference. Again, this is the reason I think so many people have a hard time getting units attached. *Added 3/6/16* I've recently come across some numbers that suggest a bucket milker only needs 2 CFM during actual milking, however when a claw falls off, it uses from 22-50 CFM.
Ok, so now that we know a bit about our needs, lets discuss our options. The most popular type of vacuum pump is a rotary vane pump. These pumps have vanes that rotate around a cylinder and use oil to seal the air and create the vacuum. These are the pumps that you sometimes see that spit oil out the exhaust. In newer applications, they have an oil reclaimer that captures this spit oil and puts it back into the system. I believe the Conde pumps mentioned earlier are this style. Along with refrigerator style pumps like Gast. Massport dairy pumps are also this style.
The other style gaining a lot of popularity is the rotary lobe pump (also called rotary lobe blowers). These are the style usually used by Boumatic and Delaval on big operations. The biggest pump manufacturers are Sutorbuilt (by Gardner Denver) and Roots (Made by Universal). These use a figure eight (or tri-lobe) style impeller spinning inside the pump housing to create the vacuum. The nice thing about this style is that the gear end, is where the oil is contained. The part creating the vacuum is dry. This allows for a cleaner experience overall. They are also extremely reliable. Some operating for decades at constant use with very little maintenance. There are other styles like Water ring pumps, etc, but they're so few and far between I don't see a big point in mentioning them.
In the end, there's nothing really special about picking a pump, you just have to know how many CFM you need, and at what vacuum level. Every pump is capable of making a certain CFM, at a certain vacuum level. The higher the vacuum needed, the lower the CFM you get. So asking to move a lot of air, at a high vacuum, requires a serious pump. One last thing to note for later, is that every pump is designed to spin at a certain RPM (revolutions per minute) range. This is important when setting up your pump-motor assembly. But we'll come back to that.
The motor:
In order to spin the vacuum pump, you have to have a motor. In some pumps, this is a pre-designed prepackaged unit. Something like a Gast pump is this way. But in most applications, the motor is a separate unit connected to your pump by a belt.
There are many different motors out there to choose from. You simply need to know a few things. For our applications, I personally think any general purpose, farm duty, or compressor duty type motor is fine. Ideally it's a TEFC (Totally Enclosed Fan Cooled) motor. These are more setup for dirty dusty environments likes barns, and have a fan to help keep them cool for long life.
All electric motors are sized according to HP. The amount of HP you'll need, depends on what the pump you have needs. And the pump manufacturer will have this information in the manual. Even if you haven't even bought the pump, they have the manuals online that usually have performance charts that help say, “at 30 CFM, the ABCD model pump, requires 2.8hp to spin at the optimum 2500rpm on the pump.” So with that type of information, we would look for a 3hp motor. Bigger is always fine. Smaller is never ok. If the motor is too small, it will work too hard to spin your pump and it will either not be able to start the pump spinning, or get very hot trying spin the pump, and end up tripping your breaker and burning itself up.
Now, there are other pieces of information needed to know when picking out your motor. First is the rpm that the motor spins at. Electric motors spin at one speed. Most spin at ~1750 rpm. This is standard. 3600 rpm motors are usually cheaper, but the faster spinning decreases the life of the motor, increases the noise, and makes pairing it with your pump a bit harder. Likewise slower rpm motors have a longer life span and will run quieter, but cost significantly more. Stick with 1750.
The other thing we need to know is the voltage and phase it runs off of. For a home, you're looking for a 120v/240v motor. Most smaller motors are wired for dual voltages. Either 120/240, bigger industrial motors will be 240/480 etc, but those are industrial applications way beyond this scope. The second part is that you want a single phase motor. This is standard household power as well. The other option is three phase, but again that's for industry.
All this might start to sound scary, but realistically it's all standard stuff. If you go down to your local TSC, they have motors on the shelf from 1/3hp to 10hp, and they're all 1750rpm, 120/240v single phase motors. They might have some 3600rpm motors too. As far as sources for motors, I'd encourage you to check ebay. There are some great deals on new motors. Nicer companies are Baldor, Leeson, Weg. Those are the standard quality brands. There are multiple electric motor wholesale websites that sell different motors as well. Simply look up the all the specs I mentioned and you should see your options.
That covers the majority of the “need to know” aspects of the two parts of your vacuum system. There are a few other things you need to keep in mind and buy if you're putting your own system together. If there's any interest I'd be happy to explain those things as well.
I'd really encourage everyone with even a bit of DIY know how to look into putting your own system together. It's really not hard. And you can build your own professionally powerful system for the cost of a typical pre-built “homeowner” level system. The “industrial nature” of vacuum pumps means that there are a lot of low cost sources for parts out there. I hate to see people pay so much for something pre-built and low performance.
I'm currently putting my own together and plan to showcase that process with photos and prices, etc.
Hope that helps. Cheers.
I'm certainly not a professional dairyman or serviceman, but I am the supervisor for a municipal water plant and take care of countless pumps and motors of all kinds. Including vacuum pumps. Likewise I'm a bit of a gear junkie.
So I thought I would make a post that might help some understand this whole vacuum pump deal. I cringe when I see people seeking out ancient surge vacuum pumps just to power their system. When they could easily get a brand new pump that would work just as well if not better.
Without further ado.
In short, the vacuum pump is what powers your whole milking system. It's responsible for sucking the milk from the cow, and in bucket milker cases, moving the pulsator as well.
There are basically two parts to your “pump” if you will. The actual pump, and the motor that powers it. There like a team. Can't have one without the other.
The pump:
The pump is what actually moves the air. And in a vacuum system we're trying to remove the air from the system. A compressor simply does the opposite. There's technically no difference between the two. However there are some unique qualities that we're looking for in a milking setup.
In a milking system, it's a relatively low vacuum situation. Vacuum is measured in “inches of mg (mercury)”. A perfect vacuum being considered roughly 29”. A typical milking system is set to around 11-13 inches. For lowline parlors, I've seen less, for high line milking parlors, sometimes more like 15 inches. What we're most concerned with in a milking system is the volume of air being moved, which is measured in cubic feet per minute (CFM). The reason being is that you need a lot of air leaving the system for everything to work. Your claw has 4 openings, that all need to be removing air to stay on, the milk takes vacuum to suck out, and transport through your system. If your cow kicks your claw and a shell falls off, it's nice when the whole claw doesn't fall off. This takes volume. The reason I mentioned the air compressor was because a lot of people think about going this route. And in most cases, with a bucket milker, it will work. The problem is that an air compressor (at least in smaller home units) is designed to move a relatively small amount of air, but at a very high pressure. So when you go to run your milking system off of it (by hooking your hoses up the opposite way as you would using it as an air compressor), it wont be moving very much air. And the additional ability of the compressor to suck a high vacuum, isn't needed. So it's a limiting piece of equipment in that regard. I would venture to say that most vacuum pumps you see for industrial applications are going to fall into this category. The cfm simply isn't there. But again, you have to know your needs in order to say.
In my opinion, based off my research for pipeline systems. Most bucket systems could stand some extra CFM. I've seen a lot of people talking about needing four hands to simultaneously put on the milking claw otherwise it wont stay on. This is because you don't have enough CFM. Watch some videos of professional parlors putting on milking units and you'll hear that “shhhhhhh” sound the whole time the unit goes on. From what I've read, no matter how few cows are on a pipeline vacuum system, they recommend 30 CFM, and an additional 5-10 CFM for each additional milking unit after about 3. The literature varies. Again, I'm a bit of a gear junkie, and want professional performance no matter what I'm doing. So I use that as my basis for decision making. Obviously with bucket systems, we don't need to slug the water through the pipeline during cleaning, which is a major need for such high CFM. But going back to pumps. Most pre-built bucket systems I've come across use a Conde brand pump. If you compare their single bucket system pump setup, it makes about 5 CFM. Quite a difference. Again, this is the reason I think so many people have a hard time getting units attached. *Added 3/6/16* I've recently come across some numbers that suggest a bucket milker only needs 2 CFM during actual milking, however when a claw falls off, it uses from 22-50 CFM.
Ok, so now that we know a bit about our needs, lets discuss our options. The most popular type of vacuum pump is a rotary vane pump. These pumps have vanes that rotate around a cylinder and use oil to seal the air and create the vacuum. These are the pumps that you sometimes see that spit oil out the exhaust. In newer applications, they have an oil reclaimer that captures this spit oil and puts it back into the system. I believe the Conde pumps mentioned earlier are this style. Along with refrigerator style pumps like Gast. Massport dairy pumps are also this style.
The other style gaining a lot of popularity is the rotary lobe pump (also called rotary lobe blowers). These are the style usually used by Boumatic and Delaval on big operations. The biggest pump manufacturers are Sutorbuilt (by Gardner Denver) and Roots (Made by Universal). These use a figure eight (or tri-lobe) style impeller spinning inside the pump housing to create the vacuum. The nice thing about this style is that the gear end, is where the oil is contained. The part creating the vacuum is dry. This allows for a cleaner experience overall. They are also extremely reliable. Some operating for decades at constant use with very little maintenance. There are other styles like Water ring pumps, etc, but they're so few and far between I don't see a big point in mentioning them.
In the end, there's nothing really special about picking a pump, you just have to know how many CFM you need, and at what vacuum level. Every pump is capable of making a certain CFM, at a certain vacuum level. The higher the vacuum needed, the lower the CFM you get. So asking to move a lot of air, at a high vacuum, requires a serious pump. One last thing to note for later, is that every pump is designed to spin at a certain RPM (revolutions per minute) range. This is important when setting up your pump-motor assembly. But we'll come back to that.
The motor:
In order to spin the vacuum pump, you have to have a motor. In some pumps, this is a pre-designed prepackaged unit. Something like a Gast pump is this way. But in most applications, the motor is a separate unit connected to your pump by a belt.
There are many different motors out there to choose from. You simply need to know a few things. For our applications, I personally think any general purpose, farm duty, or compressor duty type motor is fine. Ideally it's a TEFC (Totally Enclosed Fan Cooled) motor. These are more setup for dirty dusty environments likes barns, and have a fan to help keep them cool for long life.
All electric motors are sized according to HP. The amount of HP you'll need, depends on what the pump you have needs. And the pump manufacturer will have this information in the manual. Even if you haven't even bought the pump, they have the manuals online that usually have performance charts that help say, “at 30 CFM, the ABCD model pump, requires 2.8hp to spin at the optimum 2500rpm on the pump.” So with that type of information, we would look for a 3hp motor. Bigger is always fine. Smaller is never ok. If the motor is too small, it will work too hard to spin your pump and it will either not be able to start the pump spinning, or get very hot trying spin the pump, and end up tripping your breaker and burning itself up.
Now, there are other pieces of information needed to know when picking out your motor. First is the rpm that the motor spins at. Electric motors spin at one speed. Most spin at ~1750 rpm. This is standard. 3600 rpm motors are usually cheaper, but the faster spinning decreases the life of the motor, increases the noise, and makes pairing it with your pump a bit harder. Likewise slower rpm motors have a longer life span and will run quieter, but cost significantly more. Stick with 1750.
The other thing we need to know is the voltage and phase it runs off of. For a home, you're looking for a 120v/240v motor. Most smaller motors are wired for dual voltages. Either 120/240, bigger industrial motors will be 240/480 etc, but those are industrial applications way beyond this scope. The second part is that you want a single phase motor. This is standard household power as well. The other option is three phase, but again that's for industry.
All this might start to sound scary, but realistically it's all standard stuff. If you go down to your local TSC, they have motors on the shelf from 1/3hp to 10hp, and they're all 1750rpm, 120/240v single phase motors. They might have some 3600rpm motors too. As far as sources for motors, I'd encourage you to check ebay. There are some great deals on new motors. Nicer companies are Baldor, Leeson, Weg. Those are the standard quality brands. There are multiple electric motor wholesale websites that sell different motors as well. Simply look up the all the specs I mentioned and you should see your options.
That covers the majority of the “need to know” aspects of the two parts of your vacuum system. There are a few other things you need to keep in mind and buy if you're putting your own system together. If there's any interest I'd be happy to explain those things as well.
I'd really encourage everyone with even a bit of DIY know how to look into putting your own system together. It's really not hard. And you can build your own professionally powerful system for the cost of a typical pre-built “homeowner” level system. The “industrial nature” of vacuum pumps means that there are a lot of low cost sources for parts out there. I hate to see people pay so much for something pre-built and low performance.
I'm currently putting my own together and plan to showcase that process with photos and prices, etc.
Hope that helps. Cheers.