Diaphragm Pumps
Handling harsh chemicals or running a pump dry without wrecking it calls for a sealless design, and that is where diaphragm pumps come in. A flexing membrane draws and pushes the fluid while the drive stays isolated, so there is no shaft seal to leak and nothing but the diaphragm and valves touch the media. Buyers weigh flow, the vacuum or pressure the pump reaches, and whether the wetted materials resist their solvents. Listings describe the head construction and duty so you can match the pump to filtration, transfer or gas duties. Contact the seller to confirm chemical resistance for your fluid.
Show Filters
100%
Verified Sellers
24/7
Global Marketplace
Diaphragm Pump Types
Sitting inside the liquid handling, pumps and fluid control category, diaphragm pumps split by whether they move liquid or gas and by how many heads they run. The variants suit vacuum work, chemical transfer and metering.
Chemical resistant liquid pumps
PTFE lined heads and valves that move acids, solvents and corrosive liquids safely. They transfer aggressive fluids that would attack a metal wetted path.
Vacuum and gas transfer pumps
Oil free diaphragm units that pull rough vacuum for filtration and evaporation. Their dry running head keeps the pumped gas clean of oil mist.
Metering and dosing diaphragm pumps
Adjustable stroke designs that deliver a set volume per cycle for accurate dosing. They suit reagent addition where each shot must be repeatable.
Multi head high vacuum pumps
Two or four stage heads plumbed in series to reach deeper vacuum levels. They serve concentration and drying tasks that a single head cannot manage.
Why Choose Machinery Masters
Verified Sellers Only
Every seller is verified before a single listing goes live. Machinery Masters also reviews listings for accuracy, so buyers can commit to high value machinery with confidence.
Global Reach
Listings come from sellers across Europe, North America, and beyond. That reach widens the options past any regional dealer network, and it is often the only way to find discontinued models in good condition.
Flexible Financing Options
Qualifying listings carry financing through partner providers. Terms are shown directly on eligible product pages, spreading the cost instead of draining working capital in one hit.
Direct Seller Contact
No broker sits between the buyer and the seller. Ask about service history, arrange inspections, and negotiate directly with the person who actually knows the machine.
Applications and Uses
Diaphragm pumps handle the jobs where sealless, dry running operation matters. These are their main uses.
Vacuum filtration
Pulling liquid through membrane and depth filters for clarification and sterile filtration. The oil free head keeps the filtrate free of contamination.
Corrosive chemical transfer
Moving acids, bases and solvents that would corrode a conventional pump. PTFE wetted parts stand up to the chemistry without degrading.
Solvent evaporation support
Providing the controlled vacuum that a rotary evaporator needs to lower boiling points. A stable pull keeps distillation steady and repeatable.
Accurate reagent dosing
Delivering set volumes into a process on each stroke for repeatable addition. The adjustable stroke lets an operator tune the dose precisely.
Benefits from Machinery Masters
The marketplace gathers diaphragm pumps for chemical, vacuum and dosing duties with clear specifications.
Sealless diaphragm pumps for hard chemistry
The category collects diaphragm pumps built to move fluids that defeat sealed machines, so finding a chemically compatible head takes one search.
Used diaphragm pumps with fresh wetted parts
A serviced, used diaphragm pump with a new membrane and valves runs like new for a lower outlay, covering spare diaphragms for later.
Compatibility answered directly
You describe your solvent to the seller and confirm the wetted materials before buying, so no diaphragm meets a fluid it cannot survive.
Frequently Asked Questions About Diaphragm Pumps
Yes, dry running is one of the main strengths of a diaphragm pump because no seal depends on the fluid for lubrication. The membrane and valves tolerate running without liquid, which suits vacuum and intermittent duties. This makes them forgiving in setups where the line can empty. Even so, confirm with the seller that the specific model is rated for continuous dry service if that is your duty.
The diaphragm and valve materials decide chemical compatibility, and PTFE wetted parts resist a broad range of aggressive solvents. Check your solvent against a chemical resistance chart for the exact materials in the head. Ask the seller to confirm the diaphragm and valve composition on the listed pump. Matching these prevents the membrane swelling or failing in service.
A single head reaches rough vacuum suited to filtration and aspiration, while multi stage heads pull deeper for concentration and drying. The ultimate vacuum figure in the specification tells you the lowest pressure the pump achieves. Match that to what your application needs, since evaporation work often wants a deeper vacuum than filtration. The seller can confirm the rating and how the pump performed in service.
Diaphragm and valve life depends on the fluid, the duty cycle and the pressure the pump works against. These are wear parts designed for periodic replacement rather than lifetime service. Ask the seller when the current membrane was fitted and whether spare kits are available for the model. Planning for replacement keeps the pump reliable over the long term.
You contact the seller through the listing and can request photos, a video of the pump running or an in person inspection. Because the marketplace connects you directly with the seller, that arrangement is quick to make. Sellers are verified, which adds assurance to the exchange. Agree the inspection terms before you finalise the purchase.