O ne of the main concerns for any winery is how to move wine. Generally, the most common method used is pumping. While a pump is a pump, not all pumps are the right pumps. In this article we hope to give you the knowledge you need to make a choice that is right for you. If your operation needs a pump, which one do you use?
Criteria for Pumps
Ideally, the choice of pump used for moving wine should meet these criteria:
- Minimize shearing and agitation of the wine
- Minimize the wine’s exposure to oxygen
- Be tolerant of sediment and solids
- Be easily variable between low and high transfer rates
- Be self-priming
- Be easy to clean and sanitize
- Have equipment that is portable and can be moved easily around the winery
- A system that is easily operated and maintained by winery personnel, as well as cost effective
Piston pumps are rarely use in the wine industry. They are built around the concept of a reciprocating piston alternately sucking in low-pressure fluid then compressing and discharging the fluid to a high-pressure area. Whether the piston is connected to a crankshaft or a swash plate, the pumping concept is the same.
Piston pumps have many of the attributes required of a wine pump. They are self-priming and can provide variable flow rates efficiently. There is some shearing and agitation of the fluid being pumped but not nearly as much as there would be with a centrifugal pump.
Crankshaft-driven piston pumps are generally not reversible, though swashplate-driven pumps could be. Piston pumps are fairly tolerant of solids and sediments and, being positive-displacement pumps, can deliver high pressures.
Downsides: One of the disadvantages of piston pumps is that to reach the higher flow rates required by a modern bottling line, the pump must be so large that they are not easily portable. Another disadvantage is that the mechanical tolerances require maintenance that needs to be done by trained personnel. The relative size of piston pumps and the fact that they are not as gentle as other options make these pumps less desirable for pumping wine.
Centrifugal pumps are the type of pumps most people are familiar with. These pumps work by spinning an impeller within a volute housing that moves the liquid from the low-pressure area at the center of the impeller to the higher-pressure zone at the edge of the impeller.
Centrifugal pumps are simple to maintain, inexpensive to purchase, generate high flow rates, are somewhat tolerant of solids, and can be easily cleaned. Centrifugal pumps do not generate high-discharge pressures, so any risk of rupturing containers or hoses is minimal.
Downsides: At first glance, these look like a great choice, but they come with some disadvantages. The nature of a centrifugal pump means that they are quite rough on whatever fluid is being pumped since the fluid will experience a great deal of shearing and agitation while passing through the impeller.
Centrifugal pumps are generally not self-priming, which can make it challenging if one must suck liquid from a container lower than the pump. Centrifugal pumps provide only limited flow control by choking or opening the suction valve, which is seldom convenient for the operator to do remotely. We prefer to not move wine with centrifugal pumps.
Moineau pumps are also known as progressive cavity pumps. Rene Moineau invented the pump, but people often refer to the pumps as mono pumps or mohno pumps. The pumps work by turning a helical rotor within a helix-shaped elastomeric stator. These complex shapes create fixed volumes that move along the axis of the rotor to move fluid from one end of the pump to the other.
A Moineau pump is good for pumping wine and meets nearly all the requirements one might need. These are self-priming positive-displacement pumps that minimize the shearing and agitation of the pumped fluid. These pumps are highly tolerant of sediment and solids. The flow rates can easily be variably controlled from zero to as high as you need to go. Moineau pumps are easy to clean and maintain, and they can be packaged into compact portable packages. The pumps can get expensive but are a good value. These pumps are generally used for must.
Downsides: These pumps can be very expensive, but can work very well for large wineries with hundreds of thousands of gallons to move.
Peristaltic pumps are popular in precision pumping applications that require an exact amount be pumped per shaft rotation. The pump works by turning a lobed shaft that progressively squeezes a soft tube filled with fluid, thus pushing the fluid out of the pump on the high-pressure side of the housing.
A peristaltic pump is ideal for moving must and does well with wine. These pumps meet all the wine-pumping requirements; they are simple, reversible, easy to clean, and very gentle on the fluid being handled. These are positive-displacement pumps that are self-priming and can deliver higher flow rates. The flow rates can be easily variable, and there is very little maintenance required.
These pumps can also tolerate sediments and suspended solids without any problems. They are not inexpensive but represent a solid value with what they can do. As an additional bonus feature, these pumps may be run dry. If your intern forgets that the pump is running after a tank is empty, the pump will not be damaged.
Downsides: These pumps tend to be large and awkward, they can also have trouble going long stretches or handling elevation gains.
These are positive displacement pumps that can create moderately high pressures and can be used to pump liquids or gases. these pumps use a rubber impeller that flexes as an eccentric shaft turns within the pump body. These pumps are easy to clean and sanitize because there are fewer mechanical parts which also makes the pump more tolerant of sediment or suspended solids.
Downsides: The impeller does wear down and the ever-so-small wear particles are going to be in your wine. These pumps do not like to be run dry and can be rough on the wine. They aren’t the best for finished wine but do work well for pump overs due to their flow rate, size and portability.
Diaphragm pumps work by contracting a rubber diaphragm to pull fluid into a chamber through an inlet valve, then expanding the diaphragm to push fluid out of the chamber through an outlet valve.
This type of pump is well suited for moving wine, but it does come with limitations. It is inherently gentle while handling fluid, it is self-priming, simple, relatively inexpensive, and easy to clean. It is easy to change the flow rate of a diaphragm pump, and they are very portable. One nice feature is that it does no harm to run a diaphragm pump dry and one can even close off valves on the output side of the pump without creating any issues for the pump or hoses—it will just pause its operation.
Downsides: The disadvantages are that the pump is not easily reversible. It can be reversed, but that requires foresight and a skilled cellar worker. These pumps are often air powered and consequently would not be suitable if your building is not plumbed with compressed air. These pumps can also be difficult to properly sanitize due to the amount of moving parts that come in contact with the wine.
Gear and Rotary Lobe Pumps
Gear pumps work by moving fluid in the space outside of the gear teeth and sealing at the point where the teeth mesh. A rotary lobe pump is a variation of a gear pump but uses a “gear” with rounded lobes instead of sharp teeth.
These are very good pumps for moving wine because they do not aggressively agitate the fluid. They are easily reversible, they are tolerant of some suspended solids, and they are efficient at high and low flow rates. Gear pumps are simple and durable, portable and reliable. They are relatively cost-effective but not cheap. And gear pumps are easy to clean and sanitize.
Rotary Lobe pumps have all the advantages of gear pumps but are better at handling suspended solids and are slightly gentler with the fluid. Both gear pumps and rotary lobe pumps have finely machined tolerances that do wear out and may occasionally need to be serviced by trained personnel, but with good maintenance and care with use they can last you for the life of your winery.
These pumps are some of the most versatile and dependable around.
Downsides: Unless you get a big version of these they are not great for must. They can also be damaged by carelessness. The stainless-steel gears or lobes inside can become damage by metal staples or other objects that could get sucked through.
Some Last Considerations
Besides simply choosing the type of pump you want to get, there are other factors to consider regardless of what sort of pump you finally settle on.
- If you plan to only get one pump, we feel the Rotary Lobe pump is the best choice for your winery.
- The pump must be dressed for food-grade service. Usually this means stainless-steel construction and food-grade elastomeric seals as well as the use of food-grade lubricants.
- While many of the pumps we have discussed are capable of producing pressures in the thousands of psi, there aren’t any winery applications that require these kinds of pressures. It is prudent to use relief valves that are tested annually to avoid over-pressuring equipment. Do you know the burst and collapse pressure ratings of your tanks, barrels, and hoses?
- Giving your personnel some rudimentary training with your pumps can prevent many accidents. Considering the value of the pumping equipment and the precious wine that is being handled, it is a small investment indeed to take an hour to talk about the potential hazards of pumping and how to mitigate them.