JPS5847401Y2 - Overpressure prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overpressure prevention device used in a differential pressure transmitter for measuring fluid pressure differences.

In general differential pressure transmitters, despite the use of an overpressure protection mechanism inside the transmitter, the current situation is that the zero point and span change by several percent due to excessive differential pressure.

In today's energy-saving era, transmitters are required to be highly accurate, but when used in an actual plant, excessive pressure differentials may occur in the transmitter due to pressure fluctuations during operation, valve operation errors, etc., causing accuracy problems. It's making things worse.

This invention was made in view of the above circumstances,
It can be easily installed in the piping section, and it reliably protects the transmitter from excessive differential pressure.It is also an overpressure prevention device that can be used in places where excessive differential pressure occurs even if the transmitter itself has low pressure resistance. This is what we provide.

An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 denotes a main body interposed between the piping section and the differential pressure transmitter, and the main body 1 has an inlet 2a for guiding differential pressure measuring fluids Pa and Pb to be supplied to the differential pressure transmitter (not shown), respectively. , 2b are provided.

The intake ports 2a, 2b have small diameter constricted portions 3a,
Valve chambers 4a and 4b are connected to each other via 3b.

These valve chambers 4 a , 4 b are connected to flow paths 5 a , 5
They are separated at part b by an elastic body for differential pressure detection, such as a diaphragm 7.

Then, the outlet ports 8a, 8b are opened from the middle of the flow paths 5a, 5b, and the fluid P8. Pb flows through channels 5 a and 5 b
After filling the diaphragm 7 through the outlet port 8 a
, 8b to the differential pressure transmitter.

Further, in the valve chambers 4 a and 4 b, flow paths 5 a and 5 are provided.
Valves 10 a , 10 b are provided with sealing O-rings 9 a , 9 b having starting end side surfaces 15 a , 15 b of the valves 15 a , 15 b as valve seats.

The valves 10a and 10b are screwed onto the other ends of interlocking rods 11a and llb, each of which has one end attached to the diaphragm 7.

Further, the leaf springs 12a and 12b have screw rings 13 provided on their peripheries.
a, 13b are screwed into the guide screws 14a, 14b on the circumferential surface of the valve chambers 4a, 4b to change their positions, thereby reducing the distance between the sealing O-rings 9a, 9b and the starting end side surface 15a, 15b. It can be hatched.

Note that, as shown in FIG. 2, the leaf springs 12a and 12b are provided with through holes 15 to increase their spring properties.

In this way, the pressures Pa and Pb are determined by
, diaphragm 7, outlet ports 8a, 8b, and differential pressure transmitter.

By the way, for example, if an excessive differential pressure (p8Pb>transmitter withstanding pressure) occurs, the diaphragm 7 moves to the right in the figure, and the valve 10a also moves via the interlocking rod 11a, closing the flow path. 5a is closed as shown in FIG.

The setting of this closing pressure is based on the elastic force of the diaphragm 7, the effective area and the elastic force of the leaf springs 12a and 12b, the valve 10a,
This is done with a travel distance of 10 b.

For example, as shown in FIG.

and the withstand pressure P2 of the transmitter.

With this configuration, the fluid inflow pressure difference JP2 from the piping section is equal to the fluid inflow pressure difference JP2 and the fluid flow to the transmitter below the valve blockage point l-P, as shown in FIG. The delivery pressure difference JP3 rises and falls at the same time.

Then, when the fluid inflow pressure difference AP2 exceeds the occlusion point P1, the valve closes and the fluid delivery pressure difference I P 3 to the transmitter is held at the occlusion point P1, that is, a safe value.

Then, when the fluid inflow pressure difference A P 2 falls below the blockage point P1 again, the valve opens and the flow is performed within the safe value.

Since the present invention is configured as described above, the diaphragm 7 and the plate springs 12a, 12b, that is, the elastic body and the spring are used as the acting source, and the present invention has a relatively simple configuration, and by attaching it to the piping part, it is possible to prevent excessive difference to the transmitter. It becomes possible to prevent pressure from being sent, and it is possible to provide a transmitter with no change in zero point or span without applying excessive differential pressure to the transmitter itself.

Moreover, the small diameter provided in the intake ports 2a and 2b is
A, 3b and the elastic body 7 whose volume changes can reduce pulsations that often occur in actual plants, and can also provide a good damping effect.

Further, by providing a valve at each of the intake ports 2a and 2b, and further providing a pressure equalizing valve between the intake ports 2a and 2b, it can also be used as a three-way valve.

In the above embodiment, the elastic body 7 is a diaphragm, but the elastic body 7 is not limited to this, and may be a pressure displacement elastic body such as a bellows.

Further, in the above embodiment, sealing O-rings 9a and 9b were attached to the valves 10a and 10b, but it goes without saying that these may be made of metal touch or the like.

[Brief explanation of drawings]

The figures show one embodiment of this invention, in which Fig. 1 is a longitudinal sectional view of the central part, Fig. 2 is a side view showing the spring, Fig. 3 is a partial sectional view showing the valve in a closed state, and Fig. 4 is a longitudinal sectional view of the central part. It is a figure for explaining an effect. 2a, 2b...Intake port, 3a, 3b...
... Throttle part, 4a, 4b... Valve chamber, a, 5
b...Flow path, 7...Elastic body, 8a, 8
b...Outlet port, 10a, 10b...Valve, 12a, 12b...Spring.

Claims (1)

[Scope of utility model registration request] It has a differential pressure detection elastic body that responds to the differential pressure of the high pressure side and low pressure side differential pressure measurement fluids that are directly in contact with the front and back surfaces, respectively, and the flow path of the high pressure side and low pressure side differential pressure measurement fluids is set as above. A main body configured symmetrically around a differential pressure elastic body, a high pressure side and a low pressure side receiving port formed in this main body and communicating with a piping section for a fluid for measuring differential pressure, and a constriction section connected to each receiving port. high-pressure side and low-pressure side valve chambers that are connected to each other and are formed so as to supply the differential pressure measuring fluid introduced from the receiving port to each surface of the differential pressure elastic body, and the valve chambers are arranged within the respective valve chambers. , a pair of valves that respond to the differential pressure elastic body to block the flow of the one differential pressure measuring fluid that has reached the excessive pressure when one of the differential pressure measuring fluids becomes excessively pressurized; A pair of leaf springs are each screwed onto the valve chamber and support the valve so that the distance between the valve seat and the valve seat of the valve chamber can be adjusted; An overpressure prevention device characterized by being equipped with a pair of outlet ports for supplying to a container.