Special Operating States; Rechargeable Liquids; Marking; Direction Of Rotation Check - Richter MNKA Series Installation And Operating Instructions Manual

Sealless chemical magnetic process pump

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Installation and operating manual (30 pages)

Table Of Contents

Table of Contents

Series MNKA bearing pedestal assembly 4

2.6.2 Special operating states

In the standard version, the plain

bearing is lubricated and cooled by the

internal flushing circuit.

Due to properties of the liquid (e.g. sticking due to

inadmissible

solids

ingress), the flushing / cooling flow can be

interrupted, resulting in an inadmissible tempera-

ture rise. Ensure suitable monitoring measures.

See section 5.6.

For safe pumping operation, we recommend a

flow rate of 0.3 to 1.1 Q

outside this range, it must be ensured that the

maximum permissible flow rate according to the

pump characteristic curve is not exceeded and

that

the

maximum

temperature according to section 2.6.7 is

maintained.

If the flow rate is too high, the differential pressure

upstream and downstream of the plain bearing

may be reduced to such an extent that there is a

risk of insufficient lubrication or dry running.

If the flow rate is too low, the medium may heat up

so much due to the fluid friction that the maximum

permissible

surface

corresponding temperature class is exceeded.

Overloading, overheating or failure to observe the

design data or incorrect selection of the magnetic

coupling can lead to decoupling of the inner and

outer rotors. As a result, eddy currents are in-

duced at the inner or outer rotor and an impermis-

sible temperature rise may occur. Ensure suitable

monitoring measures. See section 5.6.

The machine NPSH value (NPSHA) should be a

minimum 0.5 m higher than the NPSH pump value

(NPSHR) to prevent a lack of lubrication or dry

running of the plain bearing.

2.6.3 Rechargeable liquids

When

operating

liquids (conductivity <10

with inert gas when draining if the

pump lining is non-conductive. See

section 6.3.

2.6.4 Marking

The Ex marking on the pump refers to

the pump part. A separate declaration

of conformity must be available for the

shaft coupling and motor or for other

attachments, and a corresponding

marking must be present.

Example of the marking on the pump part:

9250-003-en

Revision 01

TM 10458

Published 06/2022

ingress,

clogging,

gas

. When operating

Opt

permissible

operating

temperature

with

chargeable

-8

S/m), purge

When

mounting

components (e.g. motor, shaft coupling), it is

recommended to remove or obscure the Ex

marking on the pump part and, if applicable, other

attachments.

In this case, the declaration of conformity without

ATEX marking applies.

For surface temperatures that mainly depend on

the operating conditions of the pump, DIN EN

ISO 80079-36 Chapter 11.2 f) and g) state that

no temperature class or temperature may be

specified. In this case, the marking must include

temperature range identification (e.g. T4 to T3 for

gas or for dust T135 °C to T200 °C).

The temperature class is to be determined by the

operator according to section 2.6.7 Temperature

limits.

2.6.5 Direction of rotation check

If there is also a risk of explosion during the

installation phase, the direction of rotation check

must never be carried out by briefly switching on

the unfilled pump. This prevents an impermissible

increase in temperature at the plain bearing.

We recommend checking the direction of rotation

only when the coupling is disengaged or with a

rotating field meter! See also section 6.1.2.

the

2.6.6 Pump operating mode

The pump may only be started with the suction

side shut-off device fully open and the pressure

side shut-off device slightly open. It is also

possible to start the pump against a closed non-

return valve. Immediately after start-up, the

pressure-side shut-off device must be adjusted to

the operating point.