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Self-acting differential pressure controllers with flow limiter

RCQoB – flanged controllers
RCQoBm – screwed controllers

Applications

Self-acting differential pressure controllers with flow limiter are used in heating and industrial systems. Designed for maintaining differential pressure Δp between 0.2-1.6; 1-2.8 or 1-3.5 bar and preset flow rate between 0.15-23 m3/h. Compatible with cold and hot water up to 180ºC (RCQoB), up to 150ºC (RCQoBm) and non-flammable gases up to 80ºC.

Features

– differential pressure control
– controls flow rate
– installed on the return side – maintenance-free
– no external energy required

Design

All self-acting differential pressure controllers with flow limiter are medium-controlled proportional controllers. The valve disk (4) pressure is relieved by the relief unit (5) to guarantee stable regulation. The device has two components:
– control element (valve), including: valve housing (1), gland (2), seat (3), disk (4), relief unit (5), spindle (6);
– control unit (cylinder), including: impulse line (7), cylinder disks (8), springs (9), cylinder spindle (10), adjustment nut (11), cylinder housing (12).

Principle of operation

The medium flows to the valve chamber (A). The clearance between the chamber (A) and (B) is set with a gland (2). High pressure control signal is transmitted to the regulator chamber (C) via the impulse line (7). High pressure control signal is read at the beginning of the system. Pressure in the chamber (B) is supplied to the chamber (D) via the openings in the valve head (4). The change in differential pressure between the chamber (B) and the impulse line connection point forces the change in the valve head (4) position. The constant differential pressure maintains a constant pressure drop between the chambers (A, B) and ensures constant medium flow rate at the valve. The increase in regulated differential pressure over the preset value will close the head (4) until the differential pressure between the chamber (C) and (D) reaches the preset value at the spring (9). The differential pressure is set with an adjustment nut (11). The regulated flow rate is set with a gland position (2). The setting range should be a total pressure drop in the fully open system and a measuring pressure drop at the gland Δpm.

Installing controller

Controllers must be installed on horizontal lines. Flow direction must correspond to the direction of the arrow on the housing. To ensure correct operation, the rcontroller must be protected with a filter or a strainer.

Installed on the return side
Installed on the return side

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