Transfer pumps

CHEM – high precision gear pump for conveying low to medium viscosity fluids

CHEM gear pump for conveying and metering of fluids with low medium viscosity. The application range goes from classic transfer and metering tasks in the chemical and pharmaceutical industries up to the conveyance of monomers, oligomers and prepolymers during the production of polymers. Decades of experience in construction and an optimum selection of materials, make this type of pump suitable for even the most demanding tasks and are outstanding in their reliability and metering precision in both vacuum and high pressure applications. Typical areas of application for this type of pump are to be found in the chemical, cosmetic, food, petrochemical and polymer industries.

The CHEM series is also suitable for the food industry, e.g. for conveying butter, margarine or vegetable oils.

Pumps of this type can be supplied with or without heating.. The WITTE modular construction system for friction bearings, gear and shaft seals offers a maximum of flexibility for the end customer.
Technical Features

Housing
Non-alloyed and alloyed steels · tantalum · titanium · Hastelloy · ceramic

Gears
1.4112 but also all other processable ceramics and metals, e.g. 1.4571, Ferralium, ferro titanite Hastelloy, etc. · with optional surface coating · spur gearing

Friction Bearings
Carbon · NiAg (nickel-silver) · silicon carbide · zirconium oxide · tool steel · Al-bronze · special materials · with optional surface coating

Shaft Seals
Single mechanical seal (ED) · Single mechanical seal with buffer fluid (AD) · Double mechanical seal with buffer fluid (DD) · magnetic coupling · stuffing box · viscoseal

Heating Systems
Steam · water · heat transfer oil · electrical
Operating Parameters

Viscosity
0.5 to 10000000 mPas (cP)

Temperature
Up to 300°C (580°F) · higher temperatures upon request

Inlet pressure
Vacuum of max. 15 bar (215 psig), higher with magnetic drive

Conveying Pressure / Differential Pressure
Up to 120 bar (1740 psig)

The values listed are maximum values and must not coincide under certain circumstances.

Pump Sizes
From 22/6 (1.28 ccm/rev – 20 l/h) to 280/280 (12000 ccm/rev – 170000 l/h).
Application Examples

Organic and inorganic chemicals
Alcohols · additives · bases · esters · glycerine · resins · hardeners · isocyanates · monomers · oils · phenol · acids · biodiesel · asphalt · bitumen · tar · hotmelt · glues · waxes · etc.

Polymers
Celluloseacetate · Nylon 66 · prepolymers · etc.

Food industry
Vegetable oils · butter · margarine · flavourings · chocolate · fudge · liquorice · chewing gum · vitamins · syrup · gelatine · etc.

Pharmaceutical and Cosmetic Products
Amino acids · lotions · shampoo · vitamins · etc.
Mechanical Seals
Single mechanical seal (ED)
Suction pressure: up to 15 bar (abs.) (215 psig)
Viscosity: 0.2 – 5000 mPas
Temerature: max. 300°C (580°F)
Single mechanical seal with buffer fluid (AD)
Suction pressure: vacuum to max. 5 bar (abs. (75 psig)
Viscosity: 0.2 – 1000000 mPas
Temerature: max. 250°C (500°F) Double mechanical seal with buffer fluid (DD)
Suction pressure: vacuum to max 15 bar (abs.) (215 psig)
Viscosity: 0.2 – 10000000 mPas (cP)
Temerature: max 300°C (580°F)
CHEM MAGNET – with magnetic coupling – seal design for safe operation with critical media

The CHEM Magnet is in principle constructed in the same way as the CHEM but with a synchronous magnetic coupling forming the shaft seal. This operates slip-free, i.e. the pump speed is always the same as the shaft speed, as long as the load torque does not exceed the nominal torque of the magnetic coupling.

The magnetic coupling lends itself to conveying poisonous or flammable substances, as well as for operation at high system pressures. Special versions can be used for inlet pressures of up to 700 bar (10152 psig).

The containment shell of the magnetic coupling can be of the double-walled type. The double wall serves heating the coupling can. The double-walled containment shell can be provided with a leakage-monitoring system for particularly critical processes. The containment shell is filled with inert gas, in order to detect damage. If this gas escapes to the inside or outside, depending upon which wall is damaged, a pressure sensor will trigger an alarm. Because one wall of the double-walled containment shell is still intact, the possibility of the hazardous medium being conveyed leaking into the environment will be eliminated.

A particular highlight of the WITTE - Magnetic Coupling is the inner magnetic rotor's separate bearing. This ensures that only torque is transferred to the pump's drive shaft. The relatively heavy weight of the inner rotor is taken up by this bearing, thus relieving the pump's bearings.

WITTE's flange bearing design offers the additional advantage of preventing the inner totor from touching and damaging the containment shell. In competitor´s design it is possible for the inner rotor to touch the containment shell after pump bearings wear. Our design provides the safty of an additional bearing to insure the inner rotor can not touch the containment shell.