Some materials simply will not flow on their own: grease, mastic, heavy adhesive, thick food paste. To move them you need a pump that can grip a fixed slug of material and force it onward under real pressure, and that is what a piston pump does. A piston travelling back and forth inside a cylinder draws in a set volume on one stroke and pushes it out on the next, generating pressures well beyond what a centrifugal or diaphragm pump of similar size could reach.
We supply piston pumps from Graco and Aro, covering industrial and sanitary transfer, and can source other makes for a specific job. The ranges are below, or call +44 1332 913500 for help choosing.
A piston pump is a positive displacement pump in which a piston reciprocates inside a cylinder. On the suction stroke the piston pulls back, dropping the pressure so the inlet valve opens and liquid fills the cylinder. On the discharge stroke it pushes forward, the inlet valve closes and the liquid is forced out through the discharge valve at pressure.
Each stroke shifts a fixed, known volume, so output stays consistent and repeatable whatever the system pressure does. That positive displacement, plus the mechanical leverage of the piston, is what lets these pumps reach very high pressures, far higher than centrifugal or diaphragm pumps of comparable size. It also makes piston pumping the natural choice for thick materials that need real force behind them.
A single-acting pump moves liquid on one stroke, usually the forward one; a double-acting pump displaces liquid on both strokes for smoother, more continuous flow. Drive can be compressed air, an electric motor or hydraulic, but air drive is the most common in industrial transfer because it is intrinsically safe, can stall under load without harm, and varies flow simply by adjusting the air supply. The Graco and Aro ranges we supply are predominantly air-powered.
The reciprocating piston is what makes these pumps shrug off high viscosity. Thick greases, adhesives, mastics, resins, food pastes and heavy coatings that would stall a centrifugal pump are routine work for a piston transfer pump.
Standard ratio piston pumps give a fixed pressure ratio, commonly between 3:1 and 75:1, relative to the input air pressure, with higher ratios producing higher fluid pressure. Graco’s Fireball, President and Merkur ranges cover standard transfer across a wide span of ratios and flows.
Electric automatic lubrication pumps handle grease and oil dispensing on vehicles and machinery, running on an electric motor with a piston pump element rather than compressed air. The Graco G1 and G3 series are automatic grease and oil lubrication pumps of this type, used to keep equipment lubricated at set intervals.
Ram and displacement pumps empty drums, pails, hoppers and bulk containers of very thick material. The Graco Checkmate, Fast-Flo, Glutton and LD series use large-diameter pistons or follower plates to push greases, sealants and mastics out of their containers and into the supply line.
Sanitary piston transfer pumps are built in 316 stainless with FDA-compliant seals and polished fluid paths for food, beverage, pharmaceutical and cosmetic duty. The Graco Saniforce Transfer range and the EFP (Endura-Flo) series handle hygienic work where product purity and clean-in-place matter.
We supply piston pumps from Graco and Aro, and can source from other makers where a specific requirement demands it. The core ranges:
Four inputs get you to the right pump: the fluid (viscosity, chemistry, solids, temperature), the flow rate, the discharge pressure, and the power source. For viscous materials the container matters too, since drum, pail or bulk supply decides whether you want a standard pump, a ram pump with follower plate, or a transfer pump. Tell us the application on +44 1332 913500 and we will recommend the right model.
If your questions have not been answered here, get in touch with our team for more information.
A positive displacement pump that uses a reciprocating piston moving back and forth in a cylinder to transfer fluid. Each stroke shifts a fixed volume, making the output consistent and the pump capable of high pressure. Piston pumps are especially good with thick, viscous fluids like grease, adhesives, pastes and coatings.
Both are positive displacement, but the mechanism differs. A piston pump uses a reciprocating piston in a cylinder; a diaphragm pump uses a flexing membrane. Piston pumps excel at high-pressure, high-viscosity work; diaphragm pumps suit chemical transfer, abrasive slurries and duties needing leak-free containment.
The same thing as a piston pump, named for its operating principle. “Reciprocating” refers to the back-and-forth motion of the piston in the cylinder. All piston pumps reciprocate, and the term sometimes serves to set them apart from rotary positive displacement pumps such as gear or progressive cavity pumps.
A wide span, from thin solvents and water through to very thick greases, mastics, adhesives, food pastes and coatings. They are particularly suited to viscous materials other pumps cannot move, and sanitary versions with FDA-compliant wetted parts handle food, beverage, pharmaceutical and cosmetic products.
With routine maintenance, a quality piston pump such as the Graco and Aro ranges we supply gives many years of service. The main wear items are the piston packings and the valve assemblies, both straightforward to replace, and the pumps are designed for easy access to those parts. Service intervals depend on the fluid and the duty cycle.
